SafeT Work package 2
D2 report V2.0
Final
Recommendations for the enhancement of preventive tunnel safety
Version: Novermber 2005 Author: B.Martín (SICE) S. Vogler (H/B) C. Diers (H/B) M. Martens ( TNO) J. Lacroix ( DVR) M. Steiner ( ASFINAG) P.Schmitz (MRBC) M.Serrano (ETRA)
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Table of contents
1. Abstract...... 4
2. Objectives...... 5
3. Introduction...... 6
4. Data collection...... 8
5. Data analysis and practical examples...... 9 5.1 Incident detection systems and methods...... 10 5.1.1 Loop Detection Systems...... 11 5.1.2 Radar detectors...... 11 5.1.3Monitoring systems (CCTV, CCVE and Automatic Incident Detection Systems)...... 11 5.1.4 Environmental and air quality monitoring devices...... 13 5.1.5 Automatic Fire Detection Devices...... 14 5.2 Traffic management methods...... 14 5.2.1 Measures concerning construction...... 14 5.2.2 Regulations...... 20 5.2.3 Traffic control and driver behaviour with traffic controlling equipment...... 24 5.2.4 Tunnel Traffic Management...... 29 5.2.5 Measures concerning traffic observation...... 43 5.2.6 Measures concerning direct driver information...... 43 5.2.7 Conclusion...... 44 5.3 User information and communication methods...... 45 5.3.1 Introduction...... 45 5.3.2 Clear speed limits, trajectory control...... 47 5.3.3 Gradual transitions to tunnel...... 47 5.3.4 Tunnel lighting...... 48 5.3.5 VMS...... 48 5.3.6 Traffic lights and barriers...... 49 5.3.7 Information leaflets...... 50 5.3.8 Operator voice message...... 55 5.3.9 Remote supervision of emergency niche door...... 57 5.3.10 Assistance after accident...... 57 5.3.11 System guidance to emergency escape routes...... 59 5.3.12 Automatic radio information...... 62 5.3.13 Use of an emergency lane inside the tunnel...... 62 5.3.14 Design of emergency doors and exits...... 63 5.3.15 Camera surveillance...... 63 5.3.16 Communication between Rescue Units and Subway Operators.... 64 5.3.17 Use of mobile phone...... 65 5.3.18 Rescue Concepts for Public Tramway Transport...... 66 5.3.19 Height detection systems...... 68 5.3.20 Passenger Information Systems...... 69
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6. Proposal for EU guidelines...... 71 6.1 General recommendations...... 71 6.2 Incident detection systems and methods...... 71 6.3 Traffic management methods...... 71 6.4 User information and communication...... 72
7. Limitations...... 74
8. Recommendations...... 75
9. References...... 76
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1. Abstract
The purpose of this document is to provide recommendations for the enhancement of safety in European tunnels from the viewpoint of different parts involved in the safety chain and based in current experiences and methodologies/ systems used around European tunnels.
These recommendations are focused on the EU Directive with the objective of making it more useful for users, such as road authorities, tunnel operators and planners, and increase safety in tunnels. Previous to the definition of recommendations different activities took place.
Data has been collected by different means such as internet search, bibliography review, consulting to experts, international organisations such as UNECE, PIARC, World Road Association and others to provide real cases experiences.
Some gaps have been identified in data collection due to lack of reliable sources, low input obtained from other countries experiences. Thus, it is important to take into account that the recommendations produced on the EU Directive are made on this basis.
In Chapter 5 of this report “Data analysis”, information related to experiences, best practices and last technology used around Europe to improve the safety in tunnels is placed. This section is divided in three subparagraphs each of one related to: Incident detection systems & methods, traffic management methods and user information and communication methods as stated in the document of work where a detailed analysis of the different systems and methods, best practices in different European countries and recommendations are presented.
In Chapter 6 “Proposal for EU guidelines” general recommendations and specific ones are provided to the Corrigendum to Directive 2004/54/EC of the European Parliament and of the Council of 29 April 2004 on minimum safety requirements for tunnels in the trans-European road network after its deep analysis and its comparison with the data collected.
Limitations encountered during the data analysis are stated in Chapter 7.These limitations, such as reliability of data, insufficient data and other have been considered before establishing the recommendations.
From the analysis of the limitations encountered some recommendations for future work are provided in Chapter 8.
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2. Objectives
The objective of this report is to provide recommendations for the enhancement of tunnel safety based on an analysis made on current systems and methods for incident detection, traffic management and user information and communication. That analysis concerned systems and methods for incident detection, traffic management methods in order to enhance preventive safety in European road tunnels and to identify information and communication methods to promote safer driver behaviour.
Recommendations for the improvement of the safety of the existing tunnels will be made taking into account experiences and best practices in European countries. Cost of implementation and user acceptance as criteria of selection are provided only in the cases where possible. After the evaluation it has been checked that this is not a homogeneous criteria around Europe to establish recommendations.
Gaps in the EU Directive have been identified and proposals for enhancement are based on the analysis of best practices and different experiences around Europe. These real cases and new technological developments have been compared with the EU Directive always trying to follow the international standards on safety.
To elaborate this work input from WP1 related to current state of practice in tunnel safety has been taken into account and we expect that the output of this document will be useful for WP6 related to “Integrated tunnel safety management systems” and WP7 “Comprehensive guidelines on tunnels safety”.
Therefore, in this WP a detailed analysis of the current existing systems and methods for incident detection, traffic management and user information and communication has been carried out. This analysis mainly consisted of real case studies, references, and literature review such as SafeT WP1 documentation, the Directive 2004/54/CE on minimum safety requirements for tunnels in trans- European networks, its corrigendum, the PIARC document about “traffic incident management systems used in road tunnels” elaborated by the Committee on Road Tunnels and its Working Group No.4 devoted to “Communication systems and geometry” and the UNECE recommendations on this subject and other sources of information such as FIT Network, UPTUN project, SAFE TUNNEL etc. ( See references at the end of the document).
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3. Introduction
Incident detection system forms part of the traffic incident management in road tunnels. The aim of these safety management systems is to provide safe, efficient and orderly movement of traffic, as well as, minimize delays and congestion under normal traffic conditions. The Traffic Incident Management System generally consists of detection, verification and traffic / incident monitor / control devices installed inside tunnels and along approach roadways, and traffic control plans or strategies to respond to incidents. The level of automation and sophistication of such systems depends on the projected Average Annual Daily Traffic Flows (AADT), complexity of approach roadways, environment, location (urban/rural), design speeds, traffic mix (passenger vehicles, trucks, dangerous goods), tunnel geometry and operation (single or multiple tubes, uni-directional or bi-directional traffic), and height / width of tunnel for installation of variable message signs. Detection devices provide early warning of traffic incidents or abnormal conditions in the tunnel, which can result in the interruption of normal traffic flow. Verification devices and/ or traffic management methods allow tunnel operators to rapidly confirm an incident and implement incident response scenarios to systematically close lanes or redirect traffic to prevent secondary accidents, and in the event of a fire, implement safe and efficient evacuation of users by means of information and communication. Incident Management System include provisions to initiate predetermined traffic control plans to facilitate access of rescue and emergency service response teams into the tunnel.
The application of traffic management measures can be seen as an improvement of road tunnel safety. Subject to the specific basic conditions (upgrading an existing tunnel or planning a new tunnel) one has to consider well, which combination of methods is best or rather possible. Additionally it depends on various other subjects which equipment has to be recommended, for e.g. tunnel length, traffic volumes or speed.
Human factors are other of the most important part forming part of the SafeT value chain. That is why great importance has been given to user information and communication in this chapter and how the different systems can prevent incidents or users wrong behaviour in case of an incident/ accident in a tunnel.
In paragraph 5 of this report related to data analysis it can be found the information related to best practices and last technology used around Europe to improve the safety in tunnels. This section is divided in three subparagraphs each of one related to: Incident detection systems & methods, traffic management methods and user information and communication methods as stated in the document of work. In the following lines a brief description of the work done during previous tasks and that has carried us to reach these conclusions is presented. This work done is the basis for the recommendations presented in paragraph 9.
• Objectives of Task 2.1 were to identify and recommend the most appropriate devices, equipment, systems and techniques, currently being used in European tunnels in order to enhance preventive safety in existing tunnels with safety deficiencies and provide recommendations to the future ones with the aim to provide a safer environment for users and promote safer driver behaviour. For this, it was identified the incident detection and verification devices used in tunnels to provide operators with the information required to implement response scenarios, devices and systems being used by operating agencies to respond to incidents, and communicate with drivers within the tunnel. After the data analysis, an evaluation of the better systems and methods to detect and respond to traffic incidents was
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carried out based on different countries experiences, expert’s recommendations and literature review. The results of this evaluation will form the basis for recommendations. Nevertheless, it has to be contemplated that actual incident response procedures and guidelines are different for each tunnel and need to be developed by the authority responsible for the operation of the tunnel and the safety of the drivers using the tunnel. That is why human factors should be reviewed along with the hardware devices, the traffic management methods, the individual characteristics of each tunnel and the user information systems discussed in this Work Package.
• Task 2.2a was devoted to provide an overview about traffic management measures for road tunnels in the field of preventive tunnel safety .The work consisted of the analysis of the following topics:
- Measures concerning construction - Regulations - Measures concerning traffic control and driver behaviour with traffic controlling equipment - Measures concerning traffic observation - Measures concerning direct driver information
The emphasis is placed on dynamic methods in the area of preventive traffic management.
• Task 2.2.b goal was to identify (based on current literature and other European projects on tunnel safety) existing measures that have proved to mitigate the consequences of wrong behaviour during an incident/accident or list innovative measures that may avoid wrong behaviour or limit consequences of wrong behaviour after evaluation of driver information and traffic management methods , control and systems that may induce safer driver behaviour for different traffic conditions and during incidents or accident conditions . There are several ways of defining wrong behaviour in tunnels. When identifying measures to restrict consequences of wrong behaviour, it is important to think about what we consider to be wrong behaviour. Only when wrong behaviour is identified, we can think about countermeasures for this wrong behaviour. In this respect, the evaluation of methods has concentrated on wrong behaviour during incidents and accidents, so not to wrong behaviour (driving behaviour) under normal traffic conditions and user information and communication to prevent and/or mitigate this wrong behaviour.
In each of these subparagraphs an evaluation of the best practices around Europe in each subject is provided in order to serve as recommendation for future implementations in new tunnels, refurbishments in existing tunnels and as complementary information to the EU Directive 2004/54/EC on minimum safety requirements for tunnels in the Trans European Road Network.
All the data sources used to realise this evaluation can be found listed at the end of the document in paragraph 10. Furthermore, other not referred literature and experiences have been used. In these cases reference will be made within the document.
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4. Data collection
As described in previous paragraphs information has been collected by different means such as internet search, bibliography review, consulting to experts and other members to provide real cases experiences.
Each task leader has been responsible of gathering and evaluation of the information related to its task. Due to the different nature of each one of these tasks, a different approach has taken place.
For the incident detection systems and methods chapter, a detailed collection of documentation took place. Nevertheless the analysed documents are most a compendium of the standards and guidelines that are used to develop tunnel incident management systems and actual experiences with existing systems in the respective countries and/ or cases, incident management systems currently being used for single and multiple tube tunnels with unidirectional and bidirectional traffic flow. Limited reference is made to the fire detection systems as they are deeply studied in FIT ( Fire in Tunnels) project.
Data concerning “traffic management methods” was collected by analysing European national tunnels guidelines and regulations (as far as obtained by SafeT members) and experiences from various projects, supplemented by information gathered from internet search.
For the collection of data for mitigating wrong behaviour, information was gathered from research projects as the primary source of information. Since it was the idea to assess countermeasures for wrong behaviour, it was important to look at sources that actually contained information about the effectiveness of the system. A simple list of availability of products would therefore not suffice.
The reliability of the sources can only be assumed when they come from international organisations such as PIARC or UNECE and official national guidelines. New national guidelines are also reliable and reflect somehow the best practices of a country and imply a preceding cost benefit analysis. Different standards in different countries represent somehow the costs a country would accept.
The rest of the sources as described are referred and not referred literature and real cases experiences which reliability cannot be assessed by us. Furthermore, mention should be made to the low input obtained from other partners due to lack of specific information on their countries that makes us not to have information enough to provide much reliability on the sources.
Some gaps have been identified in data collection due to the same reason mentioned before. Thus, it is important to take into account that the recommendations produced on the EU Directive are made on this basis.
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5. Data analysis and practical examples
In this chapter results based on the analysis of data collected focusing on the technical points of the Directive are presented with the aim to provide guidelines on best practices and point out the limitations of the EU Directive.
In the following table it is presented the list of systems, measures and methods that have been analysed numbered as they are presented in this paragraph.
5.1 Incident detection system and methods 5.1.1 Loop detection systems 5.1.2 Radar detectors 5.1.3 Monitoring systems (CCTV, CCVE and Automatic Incident Detection Systems) 5.1.4 Environmental and air quality monitoring devices 5.1.4.1 Carbon Monoxide (CO) Detectors 5.1.4.2 Nitrous Oxide (NOx) Detectors 5.1.4.3 Beam (Opacity) 5.1.5 Automatic Fire Detection Devices 5.1.5.1 Closed Circuit Video Equipment (CCVE and CCTV): 5.1.5.2 Linear Heat Detector 5.1.5.3 Spot Detector 5.1.5.4 Manual Fire Detection 5.2 Traffic management methods 5.2.1 Measures concerning construction 5.2.1.1 Suitable Road/Tunnel Geometry 5.2.1.2 Clear Road Markings 5.2.1.3 Hard Shoulder/Lay Bys 5.2.1.4 Separate Truck Lanes 5.2.1.5 Appropriate Lighting Level inside the Tunnel 5.2.1.6 Height Detection 5.2.2 Regulations 5.2.2.1 Dangerous Goods 5.2.2.2 Minimum Maintenance 5.2.2.3 Operational Modes 5.2.2.4 Max Speed Limit in Tunnels 5.2.2.5 Vehicles 5.2.2.6 Enforcement 5.2.3 Measures concerning traffic control and driver behaviour with traffic controlling equipment 5.2.3.1 Classification of tunnels
5.2.3.2 Summary Classification of Tunnels - Evaluation 5.2.4 Tunnel Traffic Management 5.2.4.1 EU Directive 5.2.4.2 Tunnel Traffic Management Germany 5.2.4.3 Tunnel Traffic Management The Netherlands
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5.2.4.4 Tunnel Traffic Management Norway 5.2.4.5 Tunnel Traffic Management Spain 5.2.4.6 Tunnel Traffic Management in Czech 5.2.4.7 Tunnel Traffic Management in Switzerland 5.2.4.8 Summary Tunnel Traffic Management – Evaluation 5.2.5 Measures concerning traffic observation 5.2.6 Measures concerning direct driver information 5.3 User information and communication methods 5.3.2 Clear speed limits, trajectory control 5.3.3 Gradual transitions to tunnel 5.3.4 Tunnel lighting 5.3.5 VMS 5.3.6 Traffic lights and barriers 5.3.7 Information leaflets 5.3.8 Operator voice message 5.3.9 Remote supervision of emergency niche door 5.3.10 Assistance after accident 5.3.11 System guidance to emergency escape routes 5.3.12 Automatic radio information 5.3.13 Use of an emergency lane inside the tunnel 5.3.14 Design of emergency doors and exits 5.3.15 Camera surveillance 5.3.16 Communication between Rescue Units and Subway Operators 5.3.17 Use of mobile phone 5.3.18 Rescue Concepts for Public Tramway Transport 5.3.19 Height detection systems 5.3.20 Passenger Information Systems
5.1 Incident detection systems and methods
After a general evaluation of current incident detection techniques and systems and associated management for centralised and decentralised tunnel control this paragraph focus on best practices carried in European tunnels on the following concrete areas as considered the essentials to assure safety in tunnels:
- Loop detection systems - Radar detectors - Incident Detection Systems based on CCTV (Optical Systems) - Environmental and AQ monitoring devices - Automatic Fire detections systems
Last technical advances in different countries are showed in order to establish recommendations.
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5.1.1 Loop Detection Systems
Presence and speed monitoring using wire loops installed in slots cut in roadway pavement at periodic intervals. Loops sense vehicle presence by changes in inductance as the vehicle passess over the embedded loop. Speed is measured between consecutive loops. Loops are also used for traffic counting. Loop detection systems are commonly installed in tunnels meeting the design parameters for Incident Management Systems within Europe, Japan and the United States. The locations of the loop detection systems vary from tunnel entrance/exits only to equal spacing throughout the full length of the tunnel with a recommended maximum spacing of 100 meters ( in Spain it is accepted a maximum spacing of 500 meters, in Germany the maximum spacing is 300 m throughout the tunnel). The loop detection system continually provides tunnel traffic flow information to the operators located in the Control Center. Installation of a second loop adjacent to the presence loop can be used to provide accurate vehicle speed information. Analyzers for inductance presence and speed loops must be located in the tunnel near loops.
These analyzers require periodic maintenance to provide accurate information for the incident detection system. Maintenance requires tunnel closures.
Experience with loop detection systems in tunnels indicates that they provide accurate incident alarms during peak traffic conditions and catch up situations. Stalled vehicles or traffic slow downs are not easily identified by loop detection systems during off peak or low traffic conditions.
Provide information on distance between loops in each country and indicate in which countries loops are used for incident detection.
5.1.2 Radar detectors
Radar detectors are devices installed at the tunnel ceiling or sidewall to monitor speed and passage and / or presence, and inter-vehicle distance measurement when activated by a vehicle passing through its beam and reflecting a signal back toward the source.
Radar detectors are being used in tunnels in France, Spain and Germany to detect vehicle speed and distance between vehicles. Microwave beams are transmitted toward the vehicles in the tunnel and reflected back toward the radar detection system receiver. The detector measures the rebound time of the reflected signal and calculates the speed of the vehicle using the Doppler Principle. Radar detectors also measure vehicle presence and count. In general, radar detectors are installed above traffic lanes in the tunnel. Ultrasonic detection systems are similar to radar detection systems except that sound waves are used to generate the energy beam instead of microwave. The sound waves are affected by ambient noise inherent in tunnels and as a result these units are not used. Problems occur when systems are not maintained. Sensitivity of radar detectors must be adjusted for tunnel cross-sections to avoid false alarms. [10]
5.1.3 Monitoring systems (CCTV, CCVE and Automatic Incident Detection Systems)
Video surveillance equipment including automatic incident detection (AID) cameras installed in tunnels, centrally located video monitors located at a central location, pan/tilt/zoom equipment, video
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switchers, video recording equipment (VCR), AID software, AID processing equipment and communication network transmitting video signals between cameras and monitors.
Closed Circuit Television (CCTV), Closed Circuit Video Equipment (CCVE) and Automatic Incident Detection (AID) are both mandatory systems for class I and II tunnels in the tunnel directive [4] while they are recommendable or optional for the rest. National regulations in Germany, Spain France, UK, Norway, the Netherlands and Austria do not contain specific references for AIDs but CCTV is regulated depending on tunnel features, see FIT report [1]
AIDs represent a recent evolution of CCTV systems, which extends the surveillance capability of the latest to the automatic detection of incidents. In the following, the use of these systems is described.
Closed Circuit Video Equipment (CCVE) including, cameras are installed in tunnels meeting the design parameters for Incident Management Systems to monitor traffic conditions. Advances in camera designs and technology have improved video system transmission, display and data recording, provided black/white and colour video imaging, minimized the effects of vehicles headlights (blooming), and reduced equipment sizes to allow CCVE systems to be used in uni-directional and bi- directional tunnels. Camera installations in tunnels have been used to provide vehicle count and speed data to incident management systems. This information is being used to prosecute drivers exceeding tunnel speed limits and is envisioned as a deterrent in preventing accidents caused by vehicles tailgating. CCVE Systems are also used to provide incident verification.
Camera and associated hardware, including pan/tilt/zoom equipment and environmentally controlled enclosures are decreasing in size. The smaller space requirements are allowing CCVE Systems to be used in existing tunnels and tunnels with limited cross sections. Camera spacing requires line-of-sight visibility to provide video coverage of the tunnel interior. Spacing is affected by horizontal and vertical tunnel curvature, mounting height and location, and type of equipment selected. Camera locations can vary from 30 to 150 meters. New technology is available for use with new and existing tunnel cameras, and CCVE Systems to provide automatic incident detection (AID). Image processing problems have been experienced with currently available systems. System capabilities are continually improving as technology and software advances. Video processing hardware to detect incidents can be provided with new cameras and attached to existing cameras to interface with computers located in the Control Center. Software algorithms are currently available to detect stopped vehicles, congestion and changes in traffic patterns, direction of vehicle travel, speed and occupancy. AID systems provide accurate traffic information during off peak or low traffic volume conditions and can be expected to provide smoke detection based on visibility within the tunnel, and fire detection based on thermal imaging in the near future. AID systems are currently being used in many European countries ( e.g.: Spain, Germany, Norway).
Typically, AID traffic-monitoring systems consist of two main subsystems. The first part is the video processing hardware between the camera and the remote monitor. The video processing hardware can be installed on existing cameras. The standard composite video signal is sent to the remote front-end monitoring equipment using existing or new transmission cables (coaxial or fiber optic). The second part of the AID monitoring system consists of the computer workstation located at a central location. This workstation receives alarms and data from the video processing hardware and provides the operator interface. The computer workstation may also be integrated with the Traffic Management
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System. The video processing hardware runs the software algorithms processing the video data. The sophistication of the video processing algorithms varies between manufacturers.
Software algorithms for the detection of smoke and fires using CCVE systems are not currently operationally proven. To date none of the video imaging systems can be relied upon to provide reliable fire detection systems within tunnels. Smoke detection using CCVE Systems is currently available and is based on light obscuration principle, which results from a decrease in light level sensed at the camera lens. Fire detection must identify flickering light reflection characteristics of the flame, which is more complicated than the detection for smoke. The processing of video data depends upon the quality of the video signal from the camera. Variations in light and shadows, blooming and smearing of the image will degrade the performance. Tunnel noise and low quality video transmission cables will also degrade system performance.
Thermographic imaging is currently being used at the Mount Blanc Tunnel to monitor traffic approaching the tunnel to detect overheating vehicles. Any vehicle triggering an alarm will be stopped outside the tunnel.
5.1.4 Environmental and air quality monitoring devices
The following devices are currently being used to monitor environmental conditions and air quality inside vehicular tunnels:
5.1.4.1 Carbon Monoxide (CO) Detectors that measure the concentration of carbon monoxide are used to provide continuous monitoring of the tunnel air quality and are normally installed along tunnel roadways, and in the tunnel exhaust air duct where full and semi- transverse ventilation systems are used. CO output levels of modern combustible engines is decreasing due in part to improvements in technology and mandates by regulating agencies throughout the world to reduce the levels of global pollution. As a result, the dependence on monitoring CO to control tunnel ventilation systems is also decreasing in some parts of the world. The use of CO detection systems in tunnels is being evaluated in some European countries. In Germany CO detection systems are not required in tunnels below an altitude of 800 m above sea level. Opacity detectors spaced every 150 meters are provided to monitor tunnel visibility levels for these tunnels. CO detection systems are currently required in the United States for all tunnels with mechanical ventilation systems to provide automatic air quality control systems for normal traffic conditions.
5.1.4.2 Nitrous Oxide (NOx) Detectors are normally installed along the roadway to provide continuous monitoring of the tunnel air quality. NOx detectors in some countries are used in tunnels that have a high percentage of diesel-fueled vehicles.
5.1.4.3 Beam (Opacity) Detectors measure the visibility along the roadway and are used in tunnels that have a high percentage of diesel-fueled vehicles. Light emitters and receivers are installed on opposite walls of the tunnel. Under normal conditions all the light transmitted is absorbed by the light sensitive device within the receiver. As the visibility in the tunnel decreases the light intensity received also decreases. An alarm is transmitted when the light intensity level received decreases below a predetermined threshold level.
Single unit opacity detectors installed outside the active travel lanes continuously monitor visibility within road tunnels using the scattered light principle. Air drawn from the tunnel and fed into the opacity detector measures the intensity of light scattered within the sampling cell
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using a reference light beam from an internal light source. An alarm is generated when the light intensity is reduced below a predetermined threshold level.
5.1.5 Automatic Fire Detection Devices
Devices installed in the tunnel to automatically detect fires along the roadway. Systems include spot detectors and linear heat detection system.
Automatic Fire Detection Devices are not object of this paper as they are studied in FIT network. Nevertheless a brief description of the most common systems is presented:
5.1.5.1 Closed Circuit Video Equipment (CCVE and CCTV): See Incident Detection Systems
5.1.5.2 Linear Heat Detector (Automatic Detection System): Distributed Temperature Sensors (DTS). Linear temperature sensor cables installed in tunnels, usually mounted above travel lanes, that automatically actuate an alarm at a designated temperature or designated temperature gradient.
5.1.5.3 Spot Detector (Automatic Detection System): Equally spaced combination rate-of rise/fixed temperature detectors mounted above tunnel travel lanes to detect gradual and rapid changes in temperature and activate an alarm at preselected set points.
5.1.5.4 Manual Fire Detection: Manual fire alarm pull stations installed at periodic intervals in the tunnel. Manual pull stations are located in SOS / Refuge Stations or Tunnel Sidewall Niches which automatically transmit a signal to the Control Center when activated.
5.2 Traffic management methods
This chapter deals with the following traffic management methods: - Measures concerning construction - Regulations - Measures concerning traffic control and driver behaviour with traffic controlling equipment - Tunnel Traffic Management - Measures concerning traffic observation - Measures concerning direct driver information
5.2.1 Measures concerning construction
Tunnels are part of a road. The traffic terms in tunnels have to be basically the same as on roads. Nevertheless Tunnels are special sections of a road which costs a lot of money for construction, maintenance and operation. Relating to tunnels one has to consider special requirements in view to traffic safety and operation safety.
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5.2.1.1 Suitable Road/Tunnel Geometry Suitable road geometry is a basic precondition for a safe traffic flow. The earliest possibility to get influence on tunnel safety with a view to the traffic management is in the planning stage before building the tunnel.
• Number of Tubes and Lanes
The EU Directive [12] gives main criteria for deciding whether to build a single or a twin-tube tunnel: • traffic volume and safety • percentage of heavy goods vehicles • gradient and length.
“In any case, for tunnels in the design stage, a 15-year forecast shows that the traffic volume will exceed 10000 vehicles per day and lane, a twin-tube tunnel with unidirectional traffic shall be in place at the time when this value will be exceeded”. [12]
Directional traffic could be much safer than bidirectional traffic (depending on the equipment). Also twin-and more tube tunnels offer much higher safety potential in the event of a fire or other incidents.
• Cross Sections
The EU Directive gives no information about suitable cross-sectional geometry. Adequate lane widths could minimise the occurrence of accidents in one-directional and bi-directional road tunnels and offer better access for rescue services in case of an accident.
Experiences of the past are the reason for actual new guidelines in Germany [13]. Among other new regulations the BMVBW (Federal Ministry of Transport) gave some recommendations for a procedure to select tunnel cross sections. New criteria are that anomalous traffic situations like heavy traffic, planed maintenance, unplanned incidents like break down cars or accidents have to be considered in the decision for a tunnel cross section. It provides also the evidence of the usefulness of emergency lanes (hard shoulders).
Significant parameters in the procedure are • Chosen method of construction • Number of lanes per direction • Length of the tunnel • Average gradient in ascending section • Average percentage of freight transport • AADT (Average annual daily traffic)
Regular Cross Sections for tunnels in Germany are shown below.
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German regular cross section for tunnels (RAS-Q/RABT 2003) [13] In Norway the tunnel cros-sections are designated according to the total width of the road surface ( see following figure)
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The vertical clearence requirements in tunenls is 4.6 m except for pedestrian and cycle tunnels. The vertical clearence specifications apply to the vertical distance measured on the carriageway boundary. Normal cross-sections will be in excess of this to allow for: - Extra clearence for subsequent road resurfacing - Normal tolerance for tunnel linings, water and frost protection/concrete linings ( total deviation= 0.1 m) - Requirements for vertical clearance including kerbstone
Normally the tunnel cross-section will also include space for traffic signs and technical instalations. The need for extra width locally mmust be considered in each individual case. The minmum height for technical equipment must be 4.8 m above the carriageway. For laterally-mounted equipment such as traffic signs etc, the clearence must be individually determined. With consideration to emergency exits laterally mounted signd should be placed such that the minimum height below the sign is at least 2.0 m.
• Gradients
In addition to the choice of a cross section (which should not differ from the cross section outside the tunnel) the slopes are important in terms of safety. It is necessary to define a maximum and a minimum respectively for transverse gradient and longitudinal gradient.
The maximum longitudinal gradient according to the EU Directive is 5%, unless no other solution is geographically possible.
5.2.1.2 Clear Road Markings
The EU Directive gives no precise information about road markings.
To give a clear orientation for drivers in approach of the tunnel and inside the tunnel road markings are necessary. Inside the tunnel a clear demarcation between road and sidewalk is essential, this can be realized with road markings in combination with retro reflecting elements. There are different regulations in Europe concerning the colour of retro reflecting elements in road tunnels (for example: Austria: red and white, Germany, Spain: white).
Experiences in Germany with retro reflecting elements in road tunnels showed that the elements got dirty very quick and therefore lost luminance. Because of the high costs for cleaning the retro reflecting elements Germany reconsider whether it would be less expensive to use active elements which could be adjusted to the degree of staining.
Furthermore clear road markings are essential in tubes with bi-directional traffic to separate the vehicles. The separation can be improved by haptic markings or special retro reflecting nails.
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5.2.1.3 Hard Shoulder/Lay Bys
If possible and if the costs are acceptable a hard shoulder should be planned. The advantages of a hard shoulder in a tunnel tube are: • in case of broken down vehicles the traffic flow will not be disturbed and • therefore limiting the risk of rear-end collisions, • in case of an accident rescue services have better access to the scene of accident.
At least (if the realization of a hard shoulder is too expensive or there is not enough space) there should be lay bys subject to the tunnel length.
Distance between lay bys:
• EU Directive: max. 1000m for new bi-directional tunnels longer than 1500m where traffic volume is higher than 2000 vehicles per lane • Germany: max. 600m (in case of bi directional traffic across from each other to give the possibility to turn)
Sign indicating a lay by (EU-Directive) Regular length and width of a lay by (RABT2003)
In Norway distance between lay-bys is determined by the tunnel category . The location will depend upon the local circumstances including rock mechanics and geometric considerations. Further, consideration must be made to designing niches for several purposes ( e.g.: technical room, pump station, etc.). deviations in location should be within +- 50 m for emergency lay-bys and +- 100 m for turning points. In the following table normal distances between lay-bys are showed:
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According to the Directive the feasibility and effectiveness of the implementation of lay-bys shall be evaluated for existing bi-directional tunnels.
In this context it should be mentioned that a lay by was exactly the spot that enabled and motivated the truck driver in the Mont Blanc tunnel inferno to stop because he was aware that his vehicle was on fire. In these cases it could be better to try to get outside the tunnel with the burning vehicle (as it is mandatory in rail tunnels). To guarantee adequate user behavior it is necessary to inform drivers ( see point 5.3 on User information and communication) how to react in critical situations. Nevertheless lay bys are useful because of the above mentioned benefits.
5.2.1.4 Separate Truck Lanes
Separate truck lanes can be useful in case of high percentage of lorries. They can help to harmonize the traffic flow. Also in case of an installed height control a separate truck lane could be beneficial. If you have to stop a detected vehicle it is possible to stop only the traffic on the separate truck lane so that the other lanes are not affected.
Another way to separate trucks from passenger transport is to establish a temporary use. But you have to take into account that it could be a logistic problem because alternative routes for trucks or areas where the trucks can wait until passing the tunnel is allowed for trucks are needed. The Czech tunnel guideline [14] gives an example how to indicate restricted lanes by variable traffic signs (see chapter “Restricted Lane” in this report).
5.2.1.5 Appropriate Lighting Level inside the Tunnel
Inside the tunnel the field of vision for the driver is a narrow defined area. Because of that –in contrast to roads outside the tunnel- the estimation of distances and speed are more difficult. An appropriate lighting level inside the tunnel and especially in the beginning of the tunnel can minimize these effects.
An important task is to achieve the above-mentioned objectives in daytime, especially when the sun shines because of the wide difference between inside and outside the tunnel. The following photometric characteristics are considered important for appropriate tunnel lighting:
• pavement and bottom part of tunnel walls luminance level, • evenness of the luminance distribution over the pavement, • glare reduction, • light flickering reduction.
5.2.1.6 Height Detection
In order to protect the tunnel construction and equipment and for safety reasons a height detection should be installed if the tube has a limited height.
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To this purpose a vehicle height detection electronic system could be installed.
The electronic system is interconnected with a dynamical road signalling system or traffic lights. If the height limit is exceeded, the driver has to be informed ( see paragraph 5.3 related to User Information and Communication) about the violation before entering the tunnel. If a lay by is not available or the vehicle driver continues driving towards the tunnel entry, the relevant traffic lane (or direction) has to be closed immediately.
In case of stopping the traffic because of an overheigth vehicle congestions occur often. Congestions are always critical because the end of the queue is a potential risk for rear-end collision accidents. Warning the drivers in approach of the congestion and reduce the speed by dynamic traffic signs is a good measure to prevent rear-end accidents.
5.2.2 Regulations
5.2.2.1 Dangerous Goods
In case of accidents and in case of fire relating to dangerous goods, situations may appear which can not be handled by the fire brigade. The risk of loosing a lot of lifes and high dimension of damage during an incident with vehicles carrying dangerous goods has low expected frequency but a high level of negative effects.
It is strongly recommended to make an investigation of risk analysis if some alternative routes exist.
The German RABT2003 recommends two official investigation methods to get a decision for restrictions for transport of dangerous goods in road tunnels: • Project ERS2 OECD / PIARC [15] • Parts of the Swiss regulations (Richtlinien für Verkehrswege: Beurteilungskriterien II zur Störfallverordnung StFV , BUWAL August 2001) [16]
These methods / studies could be helpful and for future there should be ambitions to create a common European procedure.
To consider the transport of heavy goods there are also possibilities in the traffic management to reduce the impacts of accidents with dangerous goods: • permissions only for special times (e.g. at night when traffic volumes are low), • escorts by police (or other services) possibly by creating convoys (space for waiting vehicles is needed), • restrictions in case of high traffic density with automatic rerouting, • manual registration by mobile phone or automatic detection of vehicles with dangerous goods for the fire brigade to be prepared.
The Norwegian System TunSafe [17] is an automatic system based on detectors and cameras at each end of the tunnel. The specific electronic signature of vehicles is used to recognise vehicles entering and leaving the tunnel. The system knows the number of vehicles and what kind of vehicles are in the tunnel at any time. In case of an accident the system provides the following information for the fire brigade and tunnel operators:
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• large vehicle count both directions • small vehicle counts both directions • wind strength and direction • pictures of large vehicles in the tunnel
The pictures of the large vehicles could be used to check if vehicles with dangerous goods are in the tunnel.
Picture taken from the TunSafe leaflet, Datainstrument AS [17]
The Austrian legislation for transport of dangerous goods itemise two classes. Subject to the kind of dangerous substances in Austrian class A tunnels it is mandatory to use special warning lights at the vehicle, in class B tunnels it is mandatory that an accompanying vehicle drives behind the vehicle with dangerous goods. [18]
Class A Tunnel, including portals, length between 1000 m and < 5000 m Class B Tunnel, including portals, length more or equal to 5 000 m
In The Netherlands there are two categories of tunnels. The differences between these two categories are which dangerous goods substances are forbidden to transport through category I and category II tunnels. [19]
5.2.2.2 Minimum Maintenance Reliable technical devices are essential for tunnel safety. To guarantee the operability a minimum maintenance at regular intervals should be established.
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5.2.2.3 Operational Modes
For tunnels with more than one lane one has to consider which operational modes should be allowed. Multiple operational modes give more flexibility in various situations like closure of a tunnel tube because of an accident or maintenance, varying traffic loads subject to daytime.
For the design work, it is always necessary to consider whether the tunnel with uni-directional traffic can be used temporarily for bi-directional traffic. If the structural configuration allows this regime, and the traffic regime is designed in this way, lane signals are placed in both directions so that switching to the bi-directional regime is possible.
The Westerschelde road tunnel in The Netherlands is designed for one way traffic in two tubes in normal case. The first time maintenance work was done in tube 1, there was two way traffic in tube 2, and an accident occurred. Now, there is a guideline that during such activities, heavy goods vehicles are prohibited in the two way tube.
This example shows that it could be critical to allow trucks in bi-directional tubes, especially trucks which are extra-wide must be prohibited in every case. It should depend on traffic volumes etc. if trucks should be prohibited in bi-directional traffic (risk analysis!). It is very important to inform the tunnel user appropriately that the tube is operated bi-directional, especially in the case that bi- directional traffic is not the normal operational mode. The experiences of the police of the Elbe Tunnel in Germany showed that no more accidents occurred in bi-directional modes than in one-directional modes.
5.2.2.4 Max Speed Limit in Tunnels
With the reflection between the impacts of the traffic quality and the economic approach it is mostly acceptable to reduce the regular speed limit in relation to the normal road. Some speed limits around Europe are here presented: Germany 80 km/h Spain 80 km/h Belgium No specific regulation. Geberally, it is the same speed as open air but with some execptions ( e.g.: the tunnel of COINTE, in Liège, which is in declivity and where all the cars are limited to 80 Km/h even if it is an express way with a normal maximum speed of 120 km/h. Norway Same as on open roads, for tunnels with high traffic volumes: 70 km/h
5.2.2.5 Vehicles Another preventive measure is to create regulations to guarantee high quality of the status and equipment of vehicles. Because this issue is irrespective of traffic management measures it is not further investigated in this report.
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5.2.2.6 Enforcement To ensure that the regulations are followed by users it is important to create an enforcement structure / system.
In Germany irregular checks by the police are arranged. Additionally automatic detectors for surveying speed limit, dangerous goods vehicle, control of separation distance between vehicle should be discussed.
In Norway Automatic Speed Cameras are used.
A very promising measure was established in Austria, the so called “section control”. This system consists of • Speed surveillance depending on the vehicle category • Maximal allowed speed per vehicle category • Triggering speed (maximal allowed speed) for law enforcement remotely changeable • Automatic adaptation to new defined speed limits • Monitoring of the red light for closed lanes or tunnels • Monitoring of lanes which are closed for trucks • Ghost driver detection; image triggering and alarms • Comparing detected license numbers with a license number list of stolen vehicles • Site overview • Statistics; vehicle categories, average speed, etc
Based on first experiences in Austria with this system it was found that the number of accidents decreased. Also the average speed could be reduced (see figure below).
No Section Control Section Control Traffic Speed Traffic Speed 70-95 km/hr 55-75 km/hr
Figure 1. Accidents-injuries-fatalities in the Vienna Kaisermühlentunnel before and after Section Control. Note: Data provided by Machata, K. and Stefan, C. of KfV, Drawing by Khoury, G of FSD-SafeT-IC
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5.2.3 Traffic control and driver behaviour with traffic controlling equipment
There exist several measures concerning traffic control and driver behaviour which enhance traffic safety, for example: • Traffic signs displaying speed limit • Traffic signs displaying overtaking ban for trucks • Traffic signs displaying a mandatory distance between trucks • Lane direction control signals for supporting the driver in using the right lanes • Moveable barriers to guarantee that drivers using the right lanes • Traffic signs displaying the mandatory use of headlights • Traffic signs displaying the radio station (for messages in case of an incident)
Subject to the general conditions not every tunnel needs sophisticated technical traffic equipment. So it is reasonable to distinguish between tunnel classes.
The following chapters give an overview about classification of tunnels regarding traffic management, traffic management equipment and traffic management measures. One has to differentiate between the essential flow regulation by static traffic signs and traffic management which uses dynamic signs like variable message signs, traffic lights, etc. in dependency of the actual situation. Static traffic regulation will not be discussed in detail in the following.
5.2.3.1 Classification of tunnels
For the purpose of a standard appearance it is necessary to define standard equipment for traffic management. A standardization of traffic devices enhances the acceptance and comprehensibility for tunnel users.
The traffic management equipment and management measures have to be well adapted to the type of a tunnel. So it is reasonable to find parameters for a classification of tunnels in the field of traffic management.
• EU Directive The current Directive on minimum safety requirements for tunnels in the Trans-European Road Network establishes five levels of equipment which are based on two parameters: traffic volume (annual average daily traffic (AADT) trough a tunnel per lane) and tunnel length.
In the field of traffic management the following elements subject to the tunnel class (I to V) are listed:
Class I Class II Class III Class IV Class V ≤ 2000 AADT > 2000 AADT 500-1000 m > 1000 m 500-1000 m 1000 – 3000 m >3000 m
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• Classification in Belgium: No specific regulation. In Brussels region all the tunnels longer than 300 m are equipped with ventilation. • Classification in Germany: The German Guideline RABT 2003 differentiates in the field of traffic management between three classes. The class depends on length, traffic volume and maximum speed.
class 3
class 2
class 1
Diagram to determine the traffic management equipment (RABT 2003)
The Diagram shows that every tunnel in Germany has to be equipped with a minimum of traffic management devices (definition tunnel: length > 80m).
Subject to the basic conditions of the tunnel a higher or lower equipment class would be more appropriate:
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- low probability of traffic incidents or emergency lane in tunnel -> lower class, - bad visibility conditions, considerable gradient, need of rerouting -> class 1, - traffic control section next to tunnel portal can lead to a modified equipment. ° Classification in Norway: The classification system in Norway links tunnel geometry with necessary safety equipment. The classification complies with the EU Directive.
The traffic volume is normally given in AADT (Annual Average Daily Traffic volume). AADT is the total annual traffic divided by 365 and is given as the total traffic volume in both directions. The tunnel category is determined according to the estimated traffic volume twenty years after opening, AADT(20). Where the traffic volume varies throughout the day or over the year, or where there is considerable uncertainty in calculating AADT(20), the tunnel category may be based on selected criteria. The chosen category must be approved by the Directorate of Public Roads.
The tunnel categories are based upon traffic volume and tunnel length. (See Figure). The tunnel categories are the basis for a specific cross-section, number of traffic lanes, need for emergency lay- bys and turning points together with safety equipment.
Following figure applies to tunnels longer than 500 m. Initially, the cross-section is also selected according to this figure for shorter tunnels except that the width of the shoulder at the open road may be extended throughout the tunnel. Tunnels with a single lane (AADT< 300 on county roads) are defined as Tunnel Category A. Different cross sections apply for each category [36]
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° Classification in Spain: Spain follows the EU Directive and the French legislation, respectively. ° Classification in Czech: The basic classification in the Czech guideline depends on traffic volume and tunnel length:
According to the Czech guidelines a tunnel should be equipped in the following categories: • Minimum equipment for short tunnels;
• Minimum equipment;
• Basic equipment;
• Extended equipment. The equipment also depends on the overall traffic solution of the area or line; the final solution is also given by contingent requirements for bi-directional traffic in one tunnel tube, and by the general safety concept. The equipment selection can be made using the following figure with considering the following criteria, • Tunnel length (aggregated length of several successive tunnels),
• traffic intensity,
• maximum speed.
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Deviations in the equipment can be affected by specifics of the given solution. The subject of assessment can be, according to the Czech Guideline, for instance: • The parameter of the roads before and after the tunnel, for example at-grade intersections before and after the tunnel, TLS controlled intersections,
• characteristics of the sections in the tunnel, e.g. the tunnel traffic clearance, radio of curves, uphill or downhill gradient,
• existence of lay-bys and emergency bays,
• possibility of by-passing the tunnel section,
• anticipated accident rate;
• traffic flow composition, and other parameters.
5.2.3.2 Summary Classification of Tunnels - Evaluation
A Classification of road tunnels is useful to establish standardised traffic management equipment. The current classification in the European Directive is based on the following parameters: • tunnel length,
• traffic volume. National Guidelines like for example the Czech and the German guidelines have additional parameters which are helpful to find suitable traffic management equipment.
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5.2.4 Tunnel Traffic Management
5.2.4.1 EU Directive
In the field of traffic management equipment the EU Directive gives advices concerning Tunnel closing equipment. The given information is not specific and describes only the function and not the specific design of the equipment. The EU Directive says “Any variable message signs shall have clear indications to inform tunnel users of congestion, breakdown, accident, fire or any other hazards.”
The only signs shown in the EU Directive concerning traffic management are lane signals and they do not yet exist in international legal instruments:
5.2.4.2 Tunnel Traffic Management Germany:
As explained above there are three classes of traffic management equipment in the German Guideline RABT 2003.
o Minimum Equipment: The traffic management equipment for class 3 tunnel is shown below. Variable signs are framed black. The left column of signs shows the normal mode (no incident), the right column shows a tunnel closure.
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With this stage of equipment it is possible to close the tunnel entry in case of an incident.
o Basic Equipment: The traffic management equipment for class 2 tunnel is shown below. Variable signs are framed black. The left column of signs shows the normal mode (no incident), the right column shows a tunnel closure.
With this equipment it is possible to close the tunnel and to reduce the speed in approach of the tunnel.
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o Extended Equipment: The traffic management equipment for class 1 tunnel is shown below. The black boxes and the white rectangles are variable message signs with possible displays beside.
With this equipment the following measures are possible: • Tunnel closure
• Lane closure
• Speed reduction subject to the situation
• Warning against incidents in general, congestion, construction works, bi directional traffic
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• Bi directional traffic in one tube o Additional traffic management tools: There exist several systems which could be combined with tunnel traffic management. All systems listed below can optimise traffic flow and therefore enhance safety and reduce the probability of accidents.
° Automatic Rerouting: An Automatic rerouting system is a proper instrument to control traffic flows. In case of high traffic volumes on a tunnel route and therefore increased risk of accidents, the traffic load can be metered. Automatic rerouting could also be used if the tunnel is closed.
Example foran automatic rerouting system displaying the normal route
Example for rerouting the traffic in case of an incident
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Traffic control system in approach of the Elbtunnel, Hamburg
° Traffic Control Systems: To guarantee that the drivers can react very early in case of heavy traffic, bad weather conditions, congestions and incident /accidents adjacent traffic control systems might be useful. Traffic control systems with variable message signs in close range of tunnels may react on varies situations to harmonize the traffic flow. Measures can be to reduce speed, to warn against congestion or bad weather conditions or other irregular situations. Otherwise tunnel operators can react on situations detected by the adjacent traffic control systems, especially when the system has algorithms to predict traffic volumes or congestion detectors behind the tunnel.
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° Ramp Metering: When vehicles try to merge onto an already crowded road, everyone must brake and accelerate to jockey for space, quickly causing traffic flow to break down. Ramp meters control the frequency and the spacing of merging vehicles, minimizing speed disruptions and accident risks at the merge, which improves overall traffic flow.
Drivers waiting on the ramp for the green light to release them into the traffic flow may not appreciate that a computer constantly adjusts light cycles according to traffic flow both on the mainline and on the ramp. Pavement sensors provide traffic volumes and speeds to a software program that varies ramp release rates. The software is responsive to real-time traffic conditions.
Especially in case of access roads in areas of roads leading to a tunnel a ramp metering system can contribute to safety.
Ramp metering motorway A5 – junction Friedberg, Hessen (source: Heusch/Boesefeldt GmbH)
• Control of Separation Distance between Vehicles One of the most occurring accidents is the rear-end-collision. To prevent this risk of accidents it might be useful to control and to enforce the separation distance between vehicles.
An interesting example is the one from the Mont Blanc and Frejus tunnel in which a blue lightening every 150 m was established to indicate the minimum separation distance ( www.unece.org) but it was found that the users had difficulties to understand the purpose of the blue lightening . Furthermore one has to take into account that the minimum separation distance vary with the speed of a vehicle and fixed lightening only could indicate the distance for a certain speed.
5.2.4.3 Tunnel Traffic Management The Netherlands
° General
1. A traffic management system shall be applied: • for tunnels without an emergency lane; • if this is needed for maintenance; • if the other tunnel tube must be used for escape; • if a risk analysis shows the need for this.
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2. For maintenance the CROW guidelines for working at Highways shall be used
These guidelines prescribe that for bi-directional roads with 3 or more drive lanes per direction a traffic management system must be applied. It is assumed that the traffic intensity on a 3-lane bi- directional road is too large for a safe manual blocking.
On bi-directional roads with 2 lanes per direction it is assumed that a safe manual blocking is possible and allowed, if and only if it is certain that there will be no traffic jam.
At normal conditions blocking of a drive lane of a 2-lane bi-directional road will cause traffic jams. If a traffic intensity of more than 2000 till 2200 vehicles per hour on both drive lanes is merged on one drive lane under unfavorable conditions (for instance at lateral obstruction or a disorderly situation) blocking of a drive lane of a 2-lane bi-directional road will cause a traffic jam, if a traffic intensity of more than 1400 till 1500 vehicles per hour on both drive lanes is merged at one drive lane. It is recommended to apply a traffic management system before and inside 2-lane bi-directional road tunnels with an expected traffic intensity of more than 1500 vehicles per hour.
3. The reduction of the number of drive lanes for the handling of incidents shall take place before the entrance of the tunnel (and never inside the tunnel!). The narrowing shall be visible at a large distance for the on-coming traffic.
4. Because of the crucial character, traffic management systems shall be connected to a UPS (Uninterrupted Power Supply) to prevent sudden loss of traffic information (for instance during blocking of drive lanes at a car breakdown, an incident or an accident).
Tunnels without an alternative energy supply to guarantee the long term and permanent power supply, will (after being disconnected from the public power supply) suffer a loss of power after the operation period of the UPS.
° Traffic Detection
1. Automatic traffic detection is needed in tunnels where the tunnel design forces people to escape by the parallel traffic tube when a calamity occurs.
2. Automatic traffic detection is needed in combination with traffic jam detection systems.
3. Automatic traffic detection is needed in tunnels with operation.
A tunnel operator cannot permanently survey the traffic in a tunnel. Automatic traffic detection enables to react fast and react and anticipate on the changes in the traffic flow.
For tunnels with a traffic management system for traffic measures not meant for maintenance, an automatic traffic detection system is needed in the case of high traffic intensities, and also in the absence of an emergency lane.
For tunnels with low traffic on average, automatic traffic detection could be left out because the tunnel user can be warned in good time in case of a breakdown or incident. Besides, in tunnels with low traffic the possibility exist to warn the tunnel operator via the intercom without getting the driver in danger.
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5.2.4.4 Tunnel Traffic Management Norway
The tunnel traffic management system is based on the following concept.
a) < 5000 AADT: all tunnels have a double red light. If an extinguisher is lifted the tunnels should be closed with a red signal. The traffic Control Centre (5 in Norway) can operate the signals (however there are problems with drivers passing red signals because they believe they are out of order). b) 5000-10000 AADT: there should be a gate that can be operated from the control centre. c) > 10000 AADT will usually have video surveillance and traffic management system based on red crosses and yellow and green arrows above the roadway.
The TunSafe system mentioned in a previous chapter (“Dangerous Goods”) also provides a preventive traffic management feature. The system detects traffic volume and speed. By analyzing the speed of every vehicle entering the tunnel TunSafe can operate variable message signs.
5.2.4.5 Tunnel Traffic Management Spain
Spain follows the EU Directive and the French legislation, respectively.
5.2.4.6 Tunnel Traffic Management in Czech
° Minimum Equipment of Short Tunnels Quotation: Czech Guideline: “Minimum equipment is usually designed for tunnels with lengths up to 200m and low traffic intensity (≤ 1000 equivalent vehicles per 24 hours). This equipment comprises following permanent traffic signs: • Maximum speed
• No Overtaking
• Tunnel
• Turn on the Lights
• End of all prohibitions or other traffic signs following from the traffic solution: • No Vehicles over Height Indicated
• Overtaking by Goods Vehicles Prohibited The basis for designing traffic signalling is the TS65 “Guidelines for traffic signalling on roads”, and further the ĆSN 01 8020 “Traffic signs on roads” is used. With the minimum equipment it is not possible to affect traffic without additional measures carried out directly on site, e.g. stopping or diverting the traffic.”
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° Minimum Tunnel Equipment Quotation: Czech Guideline: “Minimum equipment has to be installed in the other tunnels (see figure below):”
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° Basic Equipment Quotation: Czech Guideline: “A possible example of the basic equipment for the TC and TB category tunnel is shown in this chapter. “
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° Extended Equipment Quotation: Czech Guideline: “Extended equipment is mostly used for the TA safety category tunnels. In this particular case lane signals, a number of other variable traffic signs, and an array of traffic signs for alternation of traffic between tunnel tubes. An example of the extended equipment is shown below.”
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° Additional traffic management tools
° Restricted Lane Quotation: Czech Guideline: “In the cases when it is necessary in a city, for instance for harmonisation of traffic stream, to ban lorry riding in a certain traffic lane/lanes in certain time intervals, it is necessary to use the VTS type of the informational sign “Restricted Lane” with a symbol of the traffic sign No. B4. The traffic sign No. IP21a of the retro reflective type is placed on the clearance profile sides, see below”
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° Information Display Quotation: Czech Guideline: “The ID provides up-to-the-minute information on special, extraordinary and emergency states in the tunnel and on adjoining road sections to road traffic participants. This information contributes to improving safety and fluency of traffic, increasing utilisation of infrastructure, but also diminishing environmental impacts on the surroundings and reducing time and power The ID provides brief and valuable information. If activation of information is not necessary, no information without meaning or having a meaning but undesirable should be visible. If information is activated, no undesirable symbols should appear. Examples of possible information: • ROAD WORK 500 M AHEAD
• OIL ON PAVEMENT, SECTION LENGTH 1 KM
• BLACK ICE BEHIND TUNNEL
• PILSEN DIRECTION CLOSED
• COLUMN OF VEHICLES 200 M AHEAD etc. ID for tunnels of the TA and TB safety categories are placed: • Before tunnel, at a distance allowing the route change;
• At tunnel portal;
• Inside tunnel. Before a tunnel, at a distance allowing the route change – drivers are informed about the situation in the tunnel and about a possibility to use an alternate road. The use of this information display is recommendatory. At portals, information is provided which explains, for example, that drivers have to wait in front of the tunnel and must not leave this space despite previous disobeying traffic rules so that they do not increase probability of causing collision situations.
Inside a tunnel, similar information is provided as that at portals. ID are installed inside the tunnel approximately after 500 m, in a sufficient advance (e.g. 100 m) of advance signal lights. It is advisable to repeat the ID information at least twice. Following imaging technologies are permitted in tunnels and on adjacent road sections: • Optical fibres (limited number of legends);
• Light-emitting diodes (LED);
• Back-lit liquid crystals (LCD);
• Bi-stable turning elements There is a requirement for the equipment within one tunnel section to be of the same technological type (LCD, bi-stable elements, …).
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Dimensions of the boards are given by the clearance profile. Boards with maximally 36 alphanumerical symbols, with body size of minimally 240 mm, are used in tunnels. They are installed above the roadway. In the portal section, unless the clearance profile is restricted, maximally three-line boards with sixteen symbols are permitted. An example of a three-line board installed at a tunnel portal is shown in the figure below.
Mobile IDs (see the TS154) are recommended for solving special or extraordinary situations. These can be positioned to any place, beyond the clearance profile, as needed – an accident, acute service action etc. Legends are modifiable according to the immediate need.”
5.2.4.7 Tunnel Traffic Management in Switzerland
An interesting example for separation distance control is the HGV metering system at the St. Gotthard Road Tunnel in Switzerland /10/.
By metering the HGV before entering the tunnel a minimum distance between HGV could be achieved. Every 20 to 60 seconds a HGV can pass through the halt towards the tunnel. This preventive traffic management measure reduces the average fire load in the tunnel. Further on an alternating one-way traffic was introduced for HGV in the St. Gottard and San Bernadino Tunnel.
5.2.4.8 Summary Tunnel Traffic Management – Evaluation
The extent of traffic management depends on tunnel classification and on tunnel structure (3 and 4 tubes, contra-flow tubes ...). Further on traffic management systems can be operated in several modes: manual by operators, semiautomatic or automatic.
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Based on the enquiry made for this report one can say that the standards for traffic management equipment are very inhomogeneous in the member states.
Additional traffic management methods which are not specific to tunnels could benefit safety, like systems harmonizing traffic before and after the portals.
5.2.5 Measures concerning traffic observation
Traffic management systems are based on traffic data. There are several methods to get these data: • Visual observation by operator,
• CCTV-cameras (closed circuit television),
• Inductive detection loops,
• SDS (speed discrimination system) in combination with a CCTV system,
• Section control (individual vehicle tracking in a section of a tunnel by means of a video camera and a laser scanner),
• Well trained tunnel operators,
• Well equipped control centres.
To have observers in the tunnel could be an option but a better overview would be granted by a video system. If you have observers in the tunnel you only have a special section which can be observed. And it is more expensive, too.
More information on this subject can be fount in paragraph 5.1 related to Incident Detection Systems.
5.2.6 Measures concerning direct driver information
Direct driver information can be realised as follows: • A warning message will be transmitted on the standard radio frequencies or by means of RDS.
• A warning message with instructions on how to act will be transmitted to the navigation devices inside the vehicles.
• A warning message will be transmitted to mobile phones of drivers inside a tunnel (this implies the obligation for drivers to turn on their mobile phone, on entering a tunnel and could only be an additional measure because the tunnel operator could not control the operational availability of the mobile phones).
• U se of an intercom system (in case traffic has (partly) already stopped.
More information on this subject can be found in next paragraph 5.3 related to User information and communication.
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5.2.7 Conclusion
There are not enough sources concerning effectiveness of traffic management methods easily available in the internet. The USA Government had established a database with information about ITS Projects and their effectiveness /12/. A similar cost benefit database in Europe would be helpful for all member states. More analyses should be carried out concerning effectiveness of traffic management measures and these analyses should be published in a database.
Because of different basic conditions of every tunnel a traffic management measure could be more or less effective. Software simulation tools can help decision-makers to analyse traffic management tools before implementation. There are several software tools using macro- and microscopic traffic models. For the Elbe Tunnel in Germany some traffic management measures were successful tested by traffic simulation ( more information related to Elbe Tunnel can be found in SafeT website www.safetunnel.net ).
The development in the field of traffic management is a living process and therefore a permanent network of traffic management experts could be very helpful to supply the Commission with actual information.
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5.3 User information and communication methods
5.3.1 Introduction
If we want to identify measures for mitigating wrong behavior it is important to keep in mind the behavior we want to mitigate. By identifying wrong behavior, safety measures follow.
If we want to know what wrong behaviour is, it is sensible to first distinguish the different phases involved in driver behaviour during incidents.
The three stages of emergency behaviour of road users that have been identified (in chronological order, Canter 1990 [25]) are:
- the interpretation stage. People see, hear and smell things in their surroundings and based on this information they try to interpret what is going on. This does not always have to be a conscious process, if people do not see things in their surroundings that worry them, they may ‘just do their thing’ without a conscious interpretation of the information. However, if there are clear cues that something is wrong, this process gets more explicit. Since this is the first step in the process towards action (or passivity), it is of crucial importance to provide the necessary information in order to allow people to make correct interpretation. - the decide what action to take stage. Based on the interpretation of the situation, people decide what to do next. Because during accidents or disasters, the information people receive is oftentimes ambiguous it may be very hard to properly decide what the best action is. Also here, any information that is non-ambiguous that may help people make the right decision needs to be provided. However, the number of hints that someone needs before to realise that something is wrong differs largely from person to person. - the deal with the emergency stage. In this stage people either tackle the crisis (which can be done in various ways), they interact with other people, escape or they remain passive (not action is also a way of dealing with the emergency, even we do not consider this an appropriate action). One important aspect of this stage is that people are unlikely to produce acts under emergencies that they would or could not produce under normal circumstances.
For engineering purposes, the 3 stages of behaviour are defined slightly differently, as Recognition, Response and Movement times. The Recognition stage directly matches the first stage described by Canter [25], the Response stage includes all actions other than movement to the exit, and thus overlaps somewhat with Canter’s second stage. The Recognition and Response stages are often referred to as “pre-movement time”, although this is slightly misleading as movement may occur. The distinction is that the movement is not directed to evacuation, but to other activities. An interrelation of the three stages is given in Figure 1.
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Pre-mov ement Recognitio n Pre-movement Interpretation phase
Response Decision what to do nex t
Movemen t Deal with the emergency
Fig 1. Interrelation of the three stages in people’s emergency behaviour
Due to the great individual differences in reaction pattern, it is difficult to predict behaviour when a catastrophe occurs. However, describing all types of behaviour shown at disasters may also learn us a lot about the necessary countermeasures in order to avoid this ‘wrong’ behaviour. The countermeasures have to be adapted to the diversity of human reactions and behaviour. This is a challenge also when security measures and emergency preparedness plans are to be developed (Steyvers et al., 1999) [35].
In general it can be stated that accidents are primarily caused by the failure of road users in flowing traffic. Therefore special attention has to be put on the listing of these wrong behaviour patterns. In consequence special meaning should be given to the prevention of these "wrong behaviour patterns” as well as the care during the conversion. When assessing all types of countermeasure that are already available, we can start by stating that the general literature regarding human behaviour in crisis situations emphasises the following aspects:
• It is vital to make people realise quickly the seriousness of a critical situation. • It is important to get people to abandon existing mind-sets and adapt their behaviour to a new situation • Clear instructions are needed to ensure that people evacuate the site by another route than they used to enter it.
Of course then the question still is: How do we do this? Though pretty much is known about causes of accidents, countermeasures are still not sufficiently efficient. What are the reasons that drivers do not properly respond to warning messages? Why do drivers not behave according to traffic rules that assure greater safety on the roads? Are they not aware of risk or is the risk not important to them? Perhaps we could agree with Lehto (1998) [29] when he mentioned that a new perspective on hazard communication places less emphasis on perceptual issues emphasised in the past (e.g. legibility, contrast, or conspicuity) but more on measuring and predicting comprehensibility, risk perception, and behavioural propensities as a function of factors such as message length and explicitness, user experience, cost of compliance, and past behavioural patterns. Edworthy (1998) [27] believes that people will decide whether or not to comply with a warning – or more generally, to show safety behaviour – if the perceived benefits of compliance appear to outweigh the costs. A person confronted with the hazard is weighing the potential benefits of appropriate safety behaviour against the costs that might be incurred in doing so. They are thus making a utility judgement which presents a cost-benefit analysis informed by the cues coming from the hazard, the individual, and from other sources. Here we are also facing the problem of risk communication (e.g. warning, traffic sign), namely the perception and interpretation of risk. There are numerous biases connected to risk, e.g. scale
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compression, underestimation of risk associated with familiar activities, optimism bias1 (= tendency for people to give lower risk estimates for themselves than for others), etc. Nevertheless - contrary to expectations - research evidence (Ayres et al., 1998) [19] suggests that behavioural choice is not closely related to subjective risk. There are other considerations that are more important, e.g. pedestrians make riskier street crossings if it is raining. It seems that often the costs of compliance with the warning or safety rule influence whether people will comply with them. It must be also mentioned that the inter-subject variability in risk perception is too high to provide a reliable basis for rational decisions and to reliably predict differences in behaviour [19]. Ayres et al. (1998) believe that instead of making decisions about acceptable levels of risk, people may seek effective ways of acting. Following Gibson (1979) [28] they proposed that by perceiving affordances2, people can choose responses without involved conscious thought about possible consequences and the chances. They are broadening the term to also include aspects of more complex situations, e.g. driving safety. Perception of affordances does not require that risk is perceived. If affordances and not risk perception is important, then the likelihood of consequences should be more important than their severity, because affordance is related to whether an action can be done successfully rather than what will happen if it fails. Warning about highly probable consequences of a certain action should therefore be more efficient than warning for an unlikely though more dangerous event. Regarding tunnels, the relatively low probability of dangerous accidents in them could be one of the causes of non-compliance with traffic rules. On the other hand, perceived affordances of undesired behaviour should be reduced. Publicized and enforced regulations could reduce the perceived likelihood of successful driving (e.g. without penalties). According to Ayres et al. (1998) in some situations it is possible to reduce perceived affordance by demonstrating personal short-term consequences or to focus directly on behavioural change (e.g. by increasing the attractiveness of a desired behaviour with incentives). Simply, risk communication campaigns are not enough, though they are much less expensive than other measures. They are good for informing people about hazards, but only in combination with enforcement and other measures they could change drivers’ behaviour toward greater safety.
5.3.2 Clear speed limits, trajectory control
If single cars exceed the speed limit, the harmonious flow of traffic is disturbed and the drivers endanger themselves, their passengers and other road users. The consequences are too small safety margins and other potential risks. In order to overcome this problem, the speed limits should be indicated at a sufficient distance before the tunnel, and speed limits should be adjusted to the lay-out of the tunnel and not standard the same as the open road before. Trajectory control would be advisable in case of extreme speeds. With trajectory control, speed is not only measured at a single location, but rather over the entire tunnel stretch. An example of trajectory control in a tunnel is for example Liege in Belgium. In order to have a better effect, it is wise to indicate that there is trajectory control.
Speed control and trajectory control are primarily needed in case that there is an expectation of a high occurrence of speed exceedance, not necessarily in all tunnels.
5.3.3 Gradual transitions to tunnel
Older, anxious and less experienced road users are inclined to reduce the driving speed under the officially allowed speed when entering the tunnel (due to the lateral narrowing caused by the tunnel
1 There is evidence that the optimism bias is due more to pessimism about others than to optimism about self when risk judgments are compared with objective risks (after Ayres et al., 1998). 2 Gibson (1979) suggested that we perceive objects or features of our environment in terms of affordances, or the uses to which they can be put. The affordances of the environment are what it offers the animal, what it provides or furnishes, either for good or ill.
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wall and the dark tunnel entrance). This is definitely a misconduct and leads to non-acceptance, reduction in safety and possibly even to aggression with other road users. It endangers the safety margin and it makes it nearly impossible (or sometimes even dangerous) to overtake them.
In order to overcome this, several things can be done. The first thing is to use a gradual transition from the open road to the tunnel. This means that in case that there is no emergency lane inside the tunnel, it is better not to remove the emergency lane close to the start of the tunnel wall, but to do this some hundreds of meters earlier. This provides drivers time to adjust their speed to the new situation. Also, people tend to change their lateral position in case of less lateral space, so they move somewhat more to the centre. By gradually removing the emergency lane, and by slowly introducing the tunnel wall, the effects on driving behaviour are limited and if effects are present, they are more gradual.
5.3.4 Tunnel lighting
Road users need to perceive all relevant visual information from a sufficient distance in order to anticipate the driving situation in time. When entering a tunnel, a possible reduction in ambient luminance may cause problems in perceiving crucial visual information inside the tunnel. Due to this limited perception, crucial information may be missed resulting to dangerous situations. The eye adaptation process and the quantity of straylights – which limits the visual perception of obstacles inside a tunnel – are the two main factors that influence the driver’s behaviour when entering tunnels.
A slow eye adaptation process occurs when the luminance levels are low. The eyes need some time to get adjusted to this lower luminance level and in this time period only objects with a luminance not far below the adaptation level outside the tunnel can be perceived. In extreme cases this decrease in luminance can be so large and sudden that for some time nothing can be perceived at all (Schreuder, 1964) [33]. This phenomenon is more intense when entering long tunnels, since then the luminance level is generally lower than outside and there is no extra light from the other end (exit) of the tunnel. The overall situation is possible to lead to serious problems if there is other traffic or an obstacle in front of the driver, which cannot be detected due to this delay in the adaptation process.
The reduced perception of the driver results in an increased uncertainty of what to expect when entering the tunnel. Contrary to the small number of experimental studies on the effect of lighting in tunnels, a lot of practical experience has been gathered through the years. Several commissions were established in order to integrate knowledge and come to general practical guidelines (CIE, 1990) [26] , (Schreuder, 1996) [34]. These reports can help designers when choosing appropriate luminance levels for specific tunnels, since these guidelines take all kinds of variables such as traffic intensity and road category into account. Counterbeam lighting, often used in Dutch tunnels, is always mentioned as an effective measure to overcome dark tunnel entrances. Also, decreasing the luminance in front of the tunnel (by special screens or trees) also helps the transition from bright to dark. At night time, the luminance at the entrance can be lower than during daylight conditions.
5.3.5 VMS
People have a reason to be at a certain place and time. An individual, for example, who has driven into a road tunnel, is determined to come out on the other side. This behaviour can be critical in crisis situations if drivers continue to enter the tunnel or try to pass an incident in order to drive out at the other end (as was originally planned). VMSs can help in two ways. On the one hand they can provide (by means of green arrows) that the situation is safe, so people know that it is safe to enter the tunnel (avoiding reduction of speed or hesitations). On the other hand, VMS can be used to reduce speed (in case of an upcoming traffic jam), close a lane and can even be used for extra information (argumentation sign).
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Visual alert messages and announcements need to be authoritative, straightforward and intuitive. In this we can talk about a lot of different measures. On the one hand this could be visual measures like traffic signalling not allowing you to enter the tunnel (e.g. red crosses above the lanes), but also all sorts of pictograms. When using variable message signs in road tunnels it is advisable to design pictograms so as to be in a position to convey the fire warning to all passengers no matter what their nationality is. This also goes for hints regarding closed tunnels and traffic jams as a consequence of fires which should be given early enough before the tunnel entrances using pictograms that are harmonized on European level.
Sometimes, for specific tunnels specific safety measures may be required. In the 6.6 km long Westerscheldetunnel in the Netherlands, specific measures were required in case of a calamity in one of the tunnel tubes. The tunnel consists of two separate tubes with each two different traffic lanes. Due to financial constraints a separate evacuation tube for pedestrians will not be built. In order to allow evacuation of road users to the other tunnel tube, transverse connections have been built between the two tubes. Since the cross-section of a tube does not allow any toom for an emergency lane or a pedestrian lane along the side of the road, car drivers escaping on foot from the unsafe tube will enter the road in the safe tunnel tube. Conflicts between moving traffic and escaping car drivers can result in another unsafe situation. In order to minimise this unsafety, some safety measures were evaluated (Martens, Koster and Lourens, 1998) [31], namely moving all traffic to the right lane and preparing the traffic for pedestrians or bringing all traffic to a complete stop. It turned out that it was not possible to stop people by means of warnings (stop, accident and read lights). It was very well possible to divert people from the lane, and using a variable message sign with an indication of running pedestrian prepared road users for pedestrians inside the tunnel. Also, the driving speed was reduced on the right driving lane (although people did not reduce their speed to 30 km/h as was indicated on the signs). This has been installed in the Westerscheldetunnel. An example is given in Figure 2 (people first see sign a, then b and then c).
(a) (b) (c) Fig 2. The warning signs as installed in the Westerscheldetunnel (only used for emergency situations).
5.3.6 Traffic lights and barriers
Only using traffic lights to close a tunnel causes problems. One reason is that on motorways red light is not expected in particular. Therefore the red light before the tunnel is simply not noticed and following drivers continue to enter the tunnel. This is also shown in various movies and films taped in real tunnel entrances.
The problem of missing the red light, recognition and observance in Austria is governed by the ASFINAG already since the year 2001. In the context of a working group consisting of tunnel experts of the ministry of transport, ASFINAG, traffic planners and traffic psychologist from the board of trustees for road safety (KfV), a package of measures has been tied. The result was incorporated into the ASFINAG guideline "design guideline of tunnel before-portal ranges". This guideline is already converted Austria far in the course of the modernization of existing tunnel as well as tunnel new buildings.
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As primary object to the approach of the tunnel the notice of the red light as well as the acceptance of the red light of traffic signalling was identified within the range of the tunnel portal. It has been seen that drivers continue to enter a tunnel even though the red light is on. The effect of a signalling and/or an advance notice is best if it only sends a strong signal to the driver if necessary, this means, if there is something unexpected. The announcement has to be repeated because of securing the message. To assure that the red light will be observed it is necessary to bring the reason for the red light in form of information to the driver.
The advance notice of the traffic light signalling devices takes place once at 1000 m before the first traffic light and once more 250 - 400 m before the first traffic light. The advance notice is equipped with two yellow signal lights which switch, in the case of traffic light is another than green, to pulsating yellow/green light.
A traffic light signalling device is attached before each tunnel in two different distances (rd. 200 m before the portal and secondly RD. 15 - 40 m before the portal) in particularly bright and large execution (LED execution, diameter 300 mm).
On the same level as the portal traffic light (15 - 40 m before the tunnel) an electronic, freely programmable LED information board with a size of 3 x 1 m is directly attached over the roadway. In succession the road user is informed by the tunnel control room about the reason for restriction of traffic in the tunnel in the form of text modules already pre-programmed. As an example the announcements: "special shipment", "breakdown in the tunnel", "ghost drivers", "accident" is mentioned.
Also, physical barriers should be put in front of the tunnel in order to physically stop people from entering the tunnel.
5.3.7 Information leaflets
Since within the EU it was also felt that road users did not have enough knowledge about how to behave in tunnels in case of an emergency, the EU leaflet (best behaviour in tunnels) was developed. Here, an example of its content is provided (see Figure 3) (although there are plans within PIARC to change its content).
In the education and training of truck and car drivers, the specific situation arising in break-downs, traffic jams, accidents and fires in tunnels should be dealt with particularly, and the correct behaviour for tunnel users should be pointed out.
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Fig 3. The EU tunnel leaflet.
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The EU leaflet is not too widespread throughout European countries, although it is available through some firms and initiatives. Of course, just handing out these leaflets does not mean that people can effectively use this information. In a TNO driving simulator experiment (done for UPTUN), the effectiveness of this folder was tested. The study showed that only about 60% of the drivers switch off the engine spontaneously, after reading the leaflet this increases to 70% (only with the help of the operator this number rises to 100%). Also, time passing after coming to a stop was longer if people did not read the leaflet and were shortest if people heard the operator voice. Not too many people use the radio to get additional information, not even after reading the leaflet. The most crucial action, that is getting out of the vehicle (or stating one would), is highly affected by the statement of the operator. Whereas 65% of the people indicate they would want or try to leave the vehicle, with 75% of the people who read the leaflet, this number increases to 94% after the operator announcement. So reading the leaflet already improves the situation somewhat compared to not getting any additional information. However, with the help of an operator's voice, performance improves even more. This leads to more people doing the right thing, but also to getting into action more quickly. Some people specifically mentioned that they planned to walk back to the entrance of the tunnel instead of using the emergency doors, which they were required to do, especially people without any additional information. Since all subjects already drove the tunnel 3 times before and had a chance to see the exits inside the tunnel on ride 4 as well, apparently some people still want to use the tunnel entry as an exit. In the last group, in which it is specifically mentioned by the operator, no-one mentioned this. This indicates that it is indeed a matter of receiving the appropriate information. Also, the use of radio information is difficult, even though some people specifically mentioned that they knew they had to use the radio for specific messages, they forgot what frequency (a specific frequency is mentioned in the leaflet). So in case there would be a radio message, it should be broadcasted via all radio channels. What remains an important area is that quite some people indicate they do not have an idea of how to handle in the given situation (even in the condition with leaflet and operator). This means that there is a lot of uncertainty in the case of accidents or incidents in tunnels, and even though there is an operator voice, even though people read the leaflet, there is still uncertainty how to behave. Keeping this in mind, it would be wise to add ‘via the emergency exits’ to the announcement ‘leave the tunnel’. This is something we have to be aware of in the near future: even though designers may think that all information needed is there, this may not be enough for the road users. Information provided needs to be over-complete, with if possible a repetition of the messages. Also, people with visible official status should be sent inside the tunnel in order to help people make the right decisions. Also, as was also discussed in the PIARC committee, we need to have people with an exemplary behavioural function, for instance professional drivers. Since these people drive tunnels more often than the average driver, their behaviour might influence other road users to do the same.
In order to promote the correct behaviour in road traffic tunnels, information campaigns on behaviour in cases of break-downs (most common event in road tunnels), traffic jams, accidents and fire in tunnels should be implemented.
If a burning vehicle is detected early and the burning develops slowly (as often is the case with a burning car), the fire often can be extinguished by means of the fire extinguishers available in the tunnel. A study prepared by PIARC showed for example that in France, about 40% of all fires occurring in tunnels could be extinguished by that way, an intervention of the fire brigade was not necessary.
Using the fire extinguishers that existed in the tunnels immediately leads to a fire alarm for the tunnel at the moment when the extinguisher is taken away from its rack. Moreover, this also displays to the monitoring station exactly where the fire occurs in the tunnel. The learners should be explained this
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fire detector function of the fire extinguishers during their training in the driving schools, so that they use purposeful the fire extinguishers of the emergency station in the tunnel in the case a fire originates at their vehicle. If in the case of vehicles transporting dangerous goods the fire has already seized the loading, the drivers presently are not allowed to intervene any more. Therefore, in these case of fires, it is absolutely essential that a fire is reported by the drivers as soon as possible indicating the kind and quantity of the dangerous good. This is the only way for the fire brigade to prepare precisely and from the very beginning the appropriate fire extinguishing and rescue measures that are specifically designed for this kind of dangerous goods.
In Germany, leaflet and a brochure (Fig. 4-6) were produced disseminated by the Federal Ministry of Transport, Housing and Building. The leaflet was produced in 2002, the brochure is quite new, dated August 2004. It does not only contain advice related to the behaviour in tunnels in case of fire, but also very useful information regarding the equipment and engineering of tunnels. The recommendations are more or less the same as in the EU leaflet, since the EU leaflet is based on the German one.
Fig. 4 Information from Federal Ministry of Transport, Housing and Building.
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Fig. 5
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Fig 6.
5.3.8 Operator voice message
In the preliminary phase of a fire, people’s behaviour is characterised by insecurity, misinterpretations, indecisiveness, while they search for information that can confirm the crisis situation (Paulsen, 1991). People do not interpret ambiguous information well. There is also an issue, whether people decide to leave their cars depending on its value or other valuable belongings in it.
In his evacuation study, Boer (2002) [21] had people evacuate in a real tunnel under experimental conditions. Two operator announcements were made. The first, issued after approximately 5 minutes, was always the same, “explosion hazard”. After another two minutes the second announcement was “leave the tunnel” or “leave the tunnel via the emergency exits".
In most tests, the tunnel was already deserted when the second announcement came, but in Test 6, there were still people present during the second announcement. Perhaps they failed to hear the first announcement. We refrain from drawing any conclusion about the effect of the second announcement. In his study, Boer claimed that considering that the first announcement was already effective, the addition "via the emergency exits" was probably not required.
From the TNO driving simulator study it was found that the operator voice (two messages: please switch off the engine, I repeat switch off the engine, and later: Please go to the emergency exits, I repeat go to the emergency exits) helped people in taking action. However, even with the announcement, there was 1 person who did not evacuate (although all persons did switch off the engine). He claimed that he did not want to panic and thought it was wiser to just wait for what else would be happening. This means that even an operator voice is not enough. The positive thing is that people responded faster and more people responded (compared to without the operator voice).
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In the case a fire breaks out, instructions in several languages such as requests to escape immediately from the tunnel or to prevent more vehicles from entering into the tunnel, should be foreseen via the public broadcast system. The use of pictograms indicating instructions are also recommended.
In the case of rail or subway tunnels, vehicles need to be equipped with facilities for a voice communication between the train conductor and an operating unit. Emergency information needs to be transmitted priority-based.
The passengers shall be informed at the stations and inside the trains about operational disturbances that might take a longer time to be put in order. Passengers have to be especially informed about substitute transportation or redirections.
From the UPTUN driving simulator study it was shown that even though some people understand that they have to handle, they do not know what is going on. This may also leas to inefficient behaviour. Also one person in that study specifically mentioned that he wondered if he was supposed to extinguish the fire or not. Data from real accidents state that people stay in their cars as long as they do not realise the threat of a real fire (MontBlanc and Tauern)
From the UPTUN project it is shown that without any prior information, only 60% of the drivers turns off the engine after coming to a complete stop for minutes in a tunnel. With extra information (reading the EU leaflet) this increases to 70% and to even 100% if the operator tells them to do so. This already indicates that people need extra guidance in extra-ordinary situations.
It is recommended that an operator voice message is pre-recorded so that the operator does not have to think about what to say, and it sounds like a strict and sound voice (if it were real life it could be that people would hear stress in the operator voice).
The operator voice will not avoid all specific behaviour found in tunnels. There is some behaviour that is found at accidents such as turning inside a tunnel or driving backwards in case of fires. Although this is anecdotal, it has been reported at various tunnel sites. One of the examples of a driving turning inside a two-directional tunnel was taped on video. Video-images are shown in Figure 2.
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Fig 2. What was on the mind of a driver trying to turn around his car in a tunnel with one way traffic. This dangerous and prohibited behaviour is caused either by limited awareness of risk or prevailing influence of some other motives. This time due to circumstances and kind behaviour of truck driver everything ended happily. But cameras in tunnels registered a number of dangerous behaviours. (Source: www.dars.si)
Although it is also stated in the EU leaflet that one should never try to turn around inside a tunnel, this behaviour is shown in real life. People tend to turn around – in case of a smoke development – if the visibility is less than 10 meters inside the tunnel. However, these values (10 meters) have been argued by experts.
In general this type of behaviour is more likely to be expected in a tunnel with 2-way traffic. In case of an accident in a one-directional tunnel, the traffic lanes will be blocked and there is no room to turn around. However in this case some people tend to back up and drive backwards out of the tunnel. Again, this is only possible in case there is no other traffic blocking the lanes.
5.3.9 Remote supervision of emergency niche door
The analysis of data reflect that the emergency call cab is often frequented but no emergency call had been set off (e.g. because of fear of a language barrier). A remote supervision of the emergency niche door may be a remedy. An automatic program should activate a rescue procedure after opening the niches door.
5.3.10 Assistance after accident
In accidents help is often rendered after a long time. Many tunnel users try to do their best to get through the accident scene without activating a direct rescue procedure as well as to contact the tunnel control center, and safeguarding opposite the victims.
In case of fire development the manual fire alarms outside the emergency niches (standard in Austria) are not used properly. Furthermore delete attempts with fire extinguishers existing in the sectors of the emergency cabins are often omitted. Immediately informing the control centre in the first phase of fire development and following instructions can prevent worse situations.
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Even though it is commonly understood in the tunnel world that people who leave their vehicle should always leave it unlocked, it is not something that is known to the public. In the evacuation project of Boer it was found that some people lock the car and some do not, basically showing that there is no clear idea on how to leave the vehicle. That people did not now know to lock it or not was also mentioned in the questionnaire of the TNO driving simulator study. Experiments from Boer (2002) [21]show that some time is lost after people leave the vehicle (with some people taking immediate action but then stay hanging around on the road. Some others go directly to the emergency exit but then when they get there they lose time hanging around in the emergency exits. There are even some people that go to the exits and then come back (to lock the car, to see what is going on, just like they wonder if they did not overreact). Some difference in behaviour between women and men has been pointed out as well, especially in fire conditions (Steyvers et al., 1999) [35]. Women’s first reaction is usually to warn the other people and they try to get out helping their relatives. However, they will not proceed to any actions for reducing the risk, for example to start putting out the fire. Men are more willing to return to the fire area, more so during the day than the night, more with than without smoke, and more with than without experience. Also, old people are more willing to take part in the fire extinguishing process than younger people. However this is actually a process that you want to avoid for heavy fires. It is very hard to extinguish a car fire (even a small one) since normally it is under the hood (you never reach the source) and if you open the hood this is very dangerous since you add oxygen to the fire. It may also not be a wise idea for people to go back to the fire scene in order to put out the fire or to help others. This should be only done by well trained firemen. People, who have come out of the fire area safely and who are willing to return to the danger zone to help other people mostly will use routes familiar to them. Only few will use routes that are unfamiliar to them.
This could be avoided by having tunnel authorities present in the tunnel, instructing people what to do. Since in most cases users are likely to miss significant parts of the initial announcements, it is important to provide this guidance in addition to the operator voice. Proulx et al (1999) [32]cite a building evacuation exercise where 72% of the occupants failed to recall the contents of the announcements.
Another factor that may prevent people from responding is fear. In the TNO driving simulator study, some people said that they did not take any action since they did not want to panic. They basically decided to remain inactive in order to remain quite. Actually this is a type of behaviour that works against you: the fear results from the feeling that something bad is going on, but then you try to fight this fear by not doing anything.
Also, if people realise the danger too late, the smoke may already have surrounded the vehicle (as was the case for the UPTUN driving simulator experiment). It happened that only closed the windows to keep the smoke outside. Only when the smoke thickened and people started to realise that something serious was going on, they could not see anymore where to go (because of the smoke) or they were too afraid that the smoke is toxic so they stayed in the vehicle. This means that proper guidance and more than one information channel is extremely important.
Authoritative guidance is imperative in the evacuation phase of an event. Reinforcing the perceived need of users (drivers and passengers) to respond requires that guidance come at least from two independent corroborating sources, i.e. a public address and uniformed employee taking control. It is suggested that repetitive announcements be made, also in other languages to reach passengers from other nations. Also, the people providing the guidance should be clearly identifiable as authorities, should be recognizable (all the same jackets) and they should receive sufficient training for doing their job.
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5.3.11 System guidance to emergency escape routes
Normally, when driving through a tunnel, people do not pay attention to emergency facilities. In case of a large accident, people may not know that there are emergency exits. Secondly, people do not notice the emergency exits in dense smoke, which was observed in the evacuation studies in dense smoke by Boer. Even when they put their hands on the wall they may just walk across an exit. This was seen in the evacuation studies.
Even though there are (although not in all) emergency rescue exits or emergency lay-bys available to bring people into safety, people tend to go for that which is safe. From real life observations it is known that if people can see the entrance, they just walk backwards. In the UPTUN TNO driving simulator study, some people also claimed to walk back to the tunnel entrance. This is strange in a sense since people had driven the tunnel 3 times before so they would have been able to see that were emergency doors available.
In another evacuation tunnel is was found that even though most people claim to go to the entrance again, not everyone really does that when brought under smoke and evacuation conditions. Then oftentimes emergency doors are also used.
Loudspeaker announcements in the tunnel itself may not be understood in the road tunnels because of the traffic noise from moving traffic and the sound reflection occurring as a consequence. To the contrary, the noise level in case of a traffic jam in the tunnel is lower and a better comprehensibility of the announcements can be expected. In the same way, road users before the closed tunnel entrances can also be informed via the loudspeakers on the reason for the closing of the tunnel.
Placing sound beacons as a form of auditory guidance should help people get to the emergency exits (Boer & Withington, 2004) [24]. Sound beacons are developed in order to overcome the problem with people passing the emergency exit in dense smoke. One of the early systems available was the SoundAlert system. In some tests they showed that 90% of the users were able to find the exits with the help of the sound beacons. However, the system is not really self-explaining since it has a rather mechanical sound. Users need to have a proper instruction and the system only gets this effective after people have had a demonstration (example of the sound) of the system. Another study showed that is people did not get any instruction, the system is not helpful anymore and it may even scare people off (it sounds like there might be a broken machine up there). A more self-explaining sound (some type of bell after which a voice speaks: Exit here and then another bell) really improves the performance up to over 90%. All subjects also exited at the nearest exit compared to 55% for the non-self-explaining sound.
All tunnels, in which the natural radiowave propagation is insufficient, should be equipped with specific communication technology. In particular tunnels of a length exceeding 600 m are to be equipped with communication technology.
Loudspeaker systems are recommended in the tunnels themselves as well as also with message sign systems before tunnel entrances or in separated cross cuts (for cases of evacuation).
In addition to sound beacons alone, a new system was developed for the UPTUN project specifically. MRSL's research has been concerned principally with researching and developing a proof-of-concept audio-visual evacuation support system, which has a number of innovative features, and which has been designed to have a very low installation and maintenance cost overhead. This is entirely consistent with the UPTUN programme’s cardinal aims of providing feasible, high effectiveness
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tunnel upgrading options with wide application potential. The system utilises a unique, contactless method of providing electrical power and bi-directional data communications to a sequence of audio- visual beacons located at regular intervals throughout the tunnel. Each of the beacons behaves in a fail-safe manner, responding to power loss or intentional initiation, with a capability of dynamic direction assignment to individual or groups of wayfinding beacons. The system also, importantly, includes provision to detect fires and monitor the critical build-up of heat and toxic combustion products throughout the escape route. The system concepts have been successfully demonstrated, and the next stage would involve further design refinement and subsequent commercial exploitation. The related UPTUN programme task and deliverable are 3.2: Development of an Evacuation Support System. A summary of MRSL’s research programme activities within UPTUN is given in Annex 1.
The system exploits a unique, distributed inductive power transfer and signalling technique, to provide a simple, low cost installation potential with high operational reliability.
Within any tunnel safety system design, there is a "cascade" of steps by importance: • Prevention of accidents • Mitigation of incident impacts • Provide a "fair chance" of escape • Facilitate rescue by third parties
MRSL's research objective has been to investigate and develop a proof-of-principle system to aid guidance and evacuation through smoke, and hence provide at least a fair chance of self-escape. Any evacuation support system must in this regard:
° Significantly increase speed of egress. ° Be useful in conditions of low visibility. ° Present unambiguous directional information. ° Make use of visual, audible and tactile cues. ° Be intuitive, with no prior training or exposure expected. ° Accommodate differences in layout, culture and language. ° Possess high integrity, preferably fail-safe operation. ° Not rely on tunnel lighting and power being present.
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Further to the above requirements, the ability to initiate or reinforce the initial evacuation response could be useful. Any tunnel evacuation support system is inevitably responding to low frequency, high severity events and it must be assumed that:
All or most tunnel occupants will be naive, with a lack of emergency experience and preparedness. Delays in emergency response and initiation of an evacuation could well be significant. That this could impact on available residence time to evacuate before reaching critical toxicity and thermal tolerance limits.
Within a developed fire situation, disorientation, panic and widely varying behaviour can be anticipated.
On balance, it was considered that the future introduction of tunnel evacuation support systems, unless prescribed by legislation, would very much depend on system standardisation, system effectiveness and minimising costs of ownership. To this end, building in added-value functions, such as a fire detection and environmental monitoring capability, was perceived to increase the likelihood of take- up. Hence a key decision was made that the MRSL system should support dual roles of wayfinding and guidance support through smoke, together with providing a multipoint tunnel environmental monitoring and fire detection capability. The system was also to be independently powered, easy to install and maintain, of fail-safe design, and have low ownership cost.
The research has involved a wide-ranging review of behavioural, human factor and physiological issues associated with evacuation. Much useful information and direction has been gained here through dialogue with Workpackage members. A major area of review has involved orientation, vision and guidance technologies, and assessing the relative value of various guidance methods. This has included acoustic, visual and tactile methods, offering both continuous or discrete guidance aids. The emphasis has been on optical wayfinding methods research, although in nil visibility, sound localisation techniques are important. Other issues considered alongside the various guidance methods have included costs and feasibility of retrofit, fitness for purpose, and anticipated occupant - system behaviour.
Against the various wayfinding techniques assessed, the following observations and conclusions can be made: • Walkways with ‘passive’ life-line or handrails provide a low cost but effective ‘fall-back’ option. • Self-powered LED strip lighting has high cost implications and was discounted. • Illumination methods have a varying ability to meet normal (unobscured) conditions and conditions of optical obscuration from smoke. • Distributed techniques such as electroluminescent conductors and optical fibre lighting are not fail-safe, i.e. once the cable is broken, illumination is lost. They also have a limited smoke penetration capability. Laser light visibility is also greatly affected by smoke.
BRE (UK) and other test data suggested that high intensity LED (light emitting diode) pictograms could be useful. A large direction arrow was used in the MRSL prototype system. In the system development stage, TNO work on arrow visibility was taken into account along with observations from mining and other hazardous industries. The scope to use future ‘ultra-high brightness’ LED technology for increased smoke penetration and visibility was taken into account along with provision of speech and other auditory signal support. The system incorporates an inbuilt dual-range CO sensor for fire detection and subsequent irrespirable atmosphere exposure monitoring of tunnel occupants. Precision temperature sensing was also incorporated to facilitate monitoring and assessment of the local environment regarding heat exposure of rescuers and evacuating personnel.
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Development of the highly innovative contactless, single-wire, inductive charging and telemetry scheme involved a significant research overhead. However, this was justified by the major installation and reliability benefits that would be gained by this approach. High standards of engineering design have been used, including the use of dedicated, low power, RISC-based microprocessors and reliability-centred software development techniques. These are considered essential to any safety- critical tunnel system. Equally, application flexibility has been accorded a high priority, and the system software should accommodate variations in tunnel scale and design.
The specific design features of the system can be summarised as follows. Each beacon is independently powered by an internal battery that is inductively charged from a line carrying a high frequency current, which couples contactlessly through each unit. There are no direct connections, each unit is isolated and significant cost and reliability benefits are anticipated from not having to use multicore cables and multipole connectors in the system. The single charging line, which can be kilometres in length, is also used to send and receive commands from individual units or groups of beacons. This provides a real-time facility to monitor environmental conditions and call alerts at each beacon, together with (potentially) a capacity to update direction information, responding to the development of a fire. Each unit is fitted with a precision temperature sensor and a dual range carbon monoxide (CO) sensor, providing an ability to detect fires and then subsequently monitor fire situations throughout the tunnel or structure. The use of a high fire withstand, ceramic clad wire is proposed for the charging line, which could in principle also provide tactile cues. The overall strategy has been to reduce beacon cost and installation complexity so as to allow beacons to be relatively closely spaced, and to provide a near continuous sequence of guidance cues, even where tunnel refuges or intermediate exits are relatively widely spaced. The MRSL system could also in principle provide an excellent platform to incorporate acoustic instruction and guidance information. With further commercial development, this proof-of-concept system is considered to have application potential across the generality of Europe’s road, railway and metro tunnels.
5.3.12 Automatic radio information
In the driving simulator study, only about 25% of the subjects tried to use the radio to get additional information. Also after reading the EU leaflet about best behaviour in tunnels (that mentions the radio as a source of information) this just increased to 33%. Somehow people are not aware of the possibility that this is an information source and that there can be an up-to-date message about the current situation. Again, even if this was mentioned in a leaflet they read just before doing the test, they still did not use this. People (if they thought about the radio) also mentioned that they forgot the radio station to tune to. It might also be the case that people think that they could not receive any radio messages inside the tunnel, and may therefore be reluctant to use the radio. If possible tunnel authorities should have the possibility to break into people’s radios and CD-players to provide specific messages. This should be interrupted at sufficiently loud sound level (if someone has the radio on low sound volume, the message should be much louder) and the messages should be very short, strict and urgent, so there is no room for misinterpretation (is this my tunnel or not?).
5.3.13 Use of an emergency lane inside the tunnel
This offers some more room for counteracting mistakes. In case there is an accident, people can use this lane to get out of the way, and emergency rescue services may have an easy access to the fire or accident location. Also a car with a breakdown situation will not increase the chances of accidents.
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However the presence of an emergency lane could also be used by people to drive out backwards or to turn inside the tunnel. If there is an emergency lane present is should always be made clear that there is no driving backwards or turning under any conditions.
5.3.14 Design of emergency doors and exits
Emergency doors should be clearly visible and identifiable. Also, they should be appealing, for instance by making them in green colors (like the emergency exit sign) and having them lit appropriately. The color green also indicates safety.
People do not like to enter doors they do not know, which is always the case in emergency doors. Behind doors there could be danger such as high tension or dangerous machinery. In a study dealing with evacuation of ship interiors (Boer, 1998; Boer & Vredeveldt, 1999) [23], 15% of the people walked passed a door that was clearly marked with an arrow and a fleeing person, despite quite circumstances. An arrow across the floor was effective, since then only 5% of the people walked passed the door. In tunnels it could be recommended to use such an arrow on the floor, pointing to the centre of the door and having a length of about 1 meter. A very good description of recommendations for signing, design and lighting of emergency doors is provided in Boer & Varkevisser (2002) [22].
5.3.15 Camera surveillance
One of the measures that has been taken in most higher priority tunnels is camera monitoring. Even though this is not a measure fighting wrong behaviour as such, it provides the opportunity to detect wrong behaviour and hopefully take the appropriate action.
In the Lincoln tunnel near Manhattan, they are currently investigating the feasibility of a new traffic metering system for the merge points. This system uses traffic signals to control the flow of merging buses. Traffic metering can increase traffic flow and reduce delays. This is a step before fighting wrong behaviour that is still worth mentioning, since it may prevent congestion in tunnels and possible accidents. Currently they are also installing electronic readers at various locations to help monitor bus movements and more accurately identify breakdowns and travel time, allowing them to make more informed routing decisions for these busses. They also plan an Intelligent Transportation System for the Lincoln Tunnel that will integrate traffic management functions and automate activities such as incident detection, customer information and inter-agency coordination. Such approaches will help manage the XBL as reliably and efficiently as possible.
It is of extreme importance that the tunnels have a smooth traffic flow rate and the mechanisms to quickly respond to any emergency events. In some tunnels this is achieved partly through an information system that automatically collects traffic data such and speed and density of traffic. This information is relayed to a safety and control office to allow quick and effective control of vehicles entering, inside and exiting the tunnel. Some tunnels also feature cameras for the instantaneous detection of non-moving vehicles to supplement the fire alarms, air quality detectors and other traffic management systems that usually determine incidents and intervention response. The interaction of traffic control plants and tunnel control equipment are of particular importance. During the conceptual design it has to made certain, that in the case of event, the tunnel possesses highest priority and that the essential information , e.g. the tunnel closure, without time delay by a far away traffic management center, are converted on location through the local tunnel control equipment.
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The ASFINAG has an Austria-wide redundant transmission network on SDH basis which connect the control centers with the individual tunnel systems. Audio communication, data and video traffic are transported in real time about this system about far distances.
Within the individual tunnel systems there exist two from each other completely independent Gigabit- Ethernet-rings which process the complete Backbonetraffic. Depending on the size of the individual tunnel systems Sub Etnernet rings with 100Mbit are subordinated under the Backbone, in particular for emergency calls, which represent the ACCESS level. Due to the coupling of the Subrings at both sides a high availability up to applications is given in each case.
As transport-laminated for applications excluding IP with UDP and TCP uses. Applications on the tunnel IP net are:
1) Field bus systems which handle the communication over minutes IEC60870-104 among themselves and to the superordinate instrumentation servers 2) Videosystems 3) Emergency call systems, which are following the emergency call protocol Standard, published from the ASFINAG, named SIPa. SIPa is based on the international open Standard SIP, developed from the Internet Task Force Organisation (IETF). It allows to transport tunnel Information data and voice about one Protocol and about one Hardware - this reduce hardware and costs in the tunnel. 4) The communication on control technology level between the field bus systems and the control technology servers as well as control applications which access on the control technology servers. When maintenance in an individual tunnel takes place the use of Wireless Lan for wireless access via service notebooks on the individual systems is possible. 5) Other Applications
All mechanisms of the IP net infrastructure are able to handle over the central management systems and can set off in the case of an error Traps via SNMP to a superordinate alarm management.
As mechanisms of the IP net infrastructure Layer-2 and Layer-3 Switches are used as well as router. The ASFINAG had published a lot of Standards in communication technology for motorway Applications. This is a very important Part for the future to guarantee the safety in tunnel systems and degrees the complexity of the systems.
5.3.16 Communication between Rescue Units and Subway Operators
In Berlin, the fire-fighters or the police can latch into the radio antennae system of the BVG. By doing so, they can communicate practically in an independent way, since several frequencies are assigned to the BVG private mobile radio, for police and the fire-fighters. Inside the tunnel, the communication is handled via the BVG slot antenna. This system produced good results. However, a new digital radio communication system is being planned. Some tests have already been carried out.
The Hamburg, the elevated railway ("Hochbahn") also disposes of radio communication opportunities of its own within the tunnel. Here, initially no voice communication opportunities with the rescue workers, the police and the fire-fighters were foreseen. About 1 years ago, the BOS channel was introduced using the IGNIS system. This channel allows a communication between all parties among one another, this is rescue workers, fire fighters and elevated railway. Although the radio coverage is
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intensely controlled again and again, radio deadspots are still detected from time to time. That was the case for example during rescue exercises in 1999 when the rescue forces in the station and at the emergency exit were unable to communicate. This also relates to the fact that the BOS channel does no longer come up to present-day needs. As yet, the German Federal States have not yet taken any decision as to what frequency is to be allotted to the digital BOS channel in future within Germany nor on a European level. For the time being, there is no chance to carry out modernisations, since the technical specifications for the future BOS-Funk are not yet cleared. There is no discussion however on the fact that in future there still needs to be a joint radio channel.
In Hanover, the discussion on future digital or analogue radio systems hampers a fast improvement of the radio systems of ÜSTRA. Radio communication during rescue measures for example will always be handled via ÜSTRA walkie-talkies, as is the case for Berlin.
In Stuttgart, problems were detected regarding the radio coverage or, respectively, the "BOS-Funk". Here, too, there is a need to clarify regarding the future radio systems. Moreover, there is a big need for action regarding the improvement of radio supply.
5.3.17 Use of mobile phone
In the UPTUN driving simulator study, some people indicated they would use their phone to call 112 (emergency alarm service). However the idea of emergency phones in tunnels is that if some-one uses that phone, immediate localisation is possible. It might be that people are not aware of this information, but even if they were they might prefer staying in their own car. This makes it hard for the person from the general emergency alarm service (not tunnel specific) to understand exactly where people are and what is going on. The phones would have led to immediate contact with the operator of that tunnel. This may also not be known to the public.
In Hamburg, mobile phones are not regarded as an appropriate tool for the information transfer such as among rescue forces working with one another. It is much more an additional opportunity for the passengers to call the attention of the public transport employees to the situation. In the future, the mobile phone will certainly not replace the safety broadcast channel, even if the tunnel is covered in terms of radio communication.
Compared to this, the situation in Hanover is somewhat different. With the exception of the fire- fighters, all of the safety forces have been equipped with mobile phones. This is how it also comes to a relief of the private mobile radio of the ÜSTRA (Public Transport System of the City of Hanover), which before was much used up to capacity, since it was used both by the fire-fighters as well as the employees.
As a result of other experiences made, relying exclusively on the mobile phone for rescue measures seems to be no good advice. So, for example, in the field of road construction in connection with the installation of telephones along German federal motorways, people assumed that installing telephones could be abandoned in the medium term. Now there are new findings available saying that in big traffic jams for example, the mobile networks broke down within seconds, since many conductors used their mobile phones at the same time. And they used their mobiles not primarily for assistance reasons but in order to change appointments. It is for this reason that a separate high-capacity safety radio systems and more powerful networks have to be set up.
Telephone companies are providing coverage for Cellular (Mobile) Telephones within existing and new tunnels. At many locations the same or separate leaky coaxial antenna cables or antennas are
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being used to provide two-way and one-way communication for the cellular, AM/FM Radio Rebroadcast and Two-Way Radio Communication Systems. Fixed signage installed outside or inside the tunnel indicating telephone numbers for reporting incidents are increasing the use of cellular telephones as a manual incident detection system. Some countries automatically direct all telephone emergency calls to the designated Emergency Control Center to minimize the burden at the Control Centers that are responsible for the day-to-day operations of the tunnel. [10]
5.3.18 Rescue Concepts for Public Tramway Transport
The demands brought forward by BOStrab (Regulations regarding tramway engineering and operation) as regards leaving the vehicle in a safe way are as follows:
- § 36, section 9
In passenger trains, there need to be installations by means of which the passengers are able to
initiate an emergency braking procedure. On tracks without a safety space and in tunnels, using
these installations outside stations must lead to an emergency stop only at the next station.
- § 43, section 6
Doors must be kept closed. In emergency cases, however, passengers must be in a position to open them.
In this context, the following questions were discussed:
How is the situation in subterranean local public transport to be assessed regarding concepts of enabling the passengers to save themselves or of being saved by rescue forces? Are there special previsions to be taken for disabled persons? The results of the discussion showed that many cities already embarked on developing detailed action plans for emergency cases. An action plan for the fire department, a joint action plan and joint fire alarm drills are also of supreme importance. In Hamburg, the fire department may also use vehicles which allow to carry out genuine fire exercises. The rescue plans and action plans for the specific stations are being elaborated in cooperation with the fire department. In order to guarantee a quick access to the stations, a big portion of the newly built stations are equipped with a safe for fire department purposes, older stations are retrofitted. The fire-fighters can open these safes by key, see from the fire detector panel where the fire is burning and pick up the keys necessary for the access to the scene of the fire. The intensive co-operation and joint exercises with the fire department are a key factor for an efficient and successful fire protection concept. The rescue concept of public transport is such that the bridging of the emergency braking avoids a forced stop of the trains in the tunnel sections between two stops. The burning vehicle is driven into the next station. This requires only a few minutes since the distances between the stations are small. As a rule, there is a sufficient number of emergency escape routes which are of a sufficient size to allow also several hundred persons to escape from fully occupied trains within short time out of the station and into fresh air.
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The overall rescue concept of public transport is devised in two steps:
(1) Self-saving concept Until the fire-fighters arrive, the passengers and staff rely on themselves for their own rescue. Public transport intents at that stage to have the burning train enter the next station. There, the passengers can leave the train in good lighting and visibility conditions. Then they can proceed with their escape out of the tunnels into fresh air through the staircases.
In case the vehicles remain unmanoeuvrable in the tunnel, the conductors are asked to organise the escape in an orderly way. In subways, part of this job is also activating the device to produce a short circuit with which all trains are fitted in order to render the power conductor without energy. In the case of vehicles operating in city railway and subway traffic, the conductors have to call the central control centre via radio communication to arrange for the deactivation of the electricity feeding.
Through the deactivation of the electricity feeding, the emergency lighting activates itself and provides for a better orientation while escaping. The behaviour in that kind of situations as well as the relevant sequence of action in cases where the passengers and staff have to save themselves, are part of the training which the conductors receive from their employers.
(2) Saving persons through others, i.e. rescue forces etc. The measures necessary for saving persons through others, i.e. rescue forces etc., need to be well coordinated between public transport operators and the rescue organisations. This requires detailed action and alarm plans of the institutions concerned. Moreover, joint section patrols (fire inspections) have to be carried out as well as emergency exercises, in order to have the mutual opportunities and procedures known and synchronised in cases when third persons are needed for rescue operations in tunnels.
In North Rhine-Westphalia, for these cases the Law on Fire Protection and Assistance after Accident which became effective in 1998, has to be considered. This law stipulates that fire inspections are compulsory. Defects detected during these fire inspections need to be settled immediately.
The Riksvei 4-Nitedal tunnel (Norway) is equipped with a redundant ring of industrial Ethernet switches. The Ethernet ring has a total length of over 5km and is used as the communications medium to control the ventilation, illumination, traffic control signs and emergency telephones.
The control station is based at the road traffic central unit in Oslo. The system comprises 11 remote I/O cabinets, four programmable logic stations and 15 video cameras.
The communications backbone is 100Mbps Ethernet in a redundant ring. Single-mode fibre is installed to ensure that the network to handle the amount of data transmitted and also to future-proof the installation as technology advances.
Ethernet has many advantages over traditional field buses; the primary advantage relates to the vastly enhanced data throughput. This enables extensive use of video cameras in conjunction with the more common control equipment, all connected to the backbone ring through Ethernet ring switches.
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Throughput can be further enhanced by implementing QoS (Quality of Service). This gains bandwidth by prioritising data into different queues; up to eight different levels of priority are available in OnTime switches used in the installation. This contrasts with the more common low and high priority. These switching features work in unison with switch criteria such as learning; where the unit learns each destination and source address for each packet. The connection between each switch is by single mode fibre configured to form a ring. The main feature of the ring is the ability of the system to detect a fibre or link failure and re-route data in the opposite direction. This process takes 30ms, a virtually seamless process that ensures important signals will not be lost. In this application, 18 ring switches automatically handle this aspect of critical network service. The ability of the network to monitor, detect and recover from this type of network failure rapidly is a major benefit to any communications infra-structure. However, if failures do occur, operators and engineers have to be made aware of their occurrence despite the network covering up the immediate effects of network breakage. Use of SNMP enables pro-and re-active network fault analysis. Network function data can be linked to a SCADA system thus enabling graphical representation of a network that operators can understand the problem regardless of network knowledge or training.
The use of video is increasing in traffic control and surveillance systems demanding increased network activity. Increased bandwidth should not necessarily cause concern if the network configuration is correctly engineered. As discussed, packet priorisation can assist network throughput.
In addition, Multicast techniques can also diminish overall network load. Multicast is when data is sent out to multiple devices on a network by a host. This can be referred to as one-to many or many- to-many. Network bandwidth can be kept to a minimum as data is routed to unique devices rather than broadcast to all devices. To enhance networks further the Internet Group Management Protocol (IGMP) can be used.
OnTime switches can act as IGMP servers. In principle, when a video camera has traffic for a destination, 'join' information is sent to switches containing relevant addresses. The switches then direct traffic to the required ports using multicast filtering. Therefore, the total traffic amount is kept to a minimum. Finally, when a camera or device has finished sending video, a 'leave' message is sent to the required switches so data is not sent to redundant devices.
Apart from the requirement for a fast fail-over, the industrial switches supplied for the project were specified from -40 to +70°C operational temperature range. The power consumption also had to be compatible with an UPS system.
5.3.19 Height detection systems
In most tunnels in the Netherlands (e.g. Coentunnel near Amsterdam), a height detection system is used. At a sufficient distance before the tunnel, a height detection system checks truck. If the truck is found to be too large, the truck driver is stopped by the tunnel operator and asked to leave the motorway at the next exit in order to avoid the truck from getting stuck. The operator center gets in automatic alarms and need to respond by direct voice contact with the truck driver.
To increase the tunnel security the implementation of height detection systems can be advised. On the one hand the damage of the tunnel and/or in particular the tunnel mechanism is avoided (lighting and ventilation), and on the other hand it prevents the event that load is stripped off by the truck and endangers following traffic.
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With the rising traffic intensity and number of lanes the problem with monitoring and filtering the over-high vehicles rises. In Austria HDS exist in optical form in the access area of the tunnels. The height control takes place in sufficient distance to a parking area (about 250 m). There an electronic information board is alternating signing: "extent limit" and "truck→ "). This parking area is equipped with a telephone mechanism to tunnel control room, a video monitoring and a loudspeaker, so that the truck driver can receive further instructions.
5.3.20 Passenger Information Systems
In public transport tunnels (rail, subway and tram), passenger information systems with the aim of preventive traffic education should include:
(a) Advertising Spots Advertising spots regarding safety enjoy a high degree of attention. They can, however, also suggest the impression that the intention of these spots is to conceal a lack of fire protection measures of the operational business. (b) Newsletters for the customers by the public transportation service Some public transportation services disseminate an own newspaper to their passengers every month and free of charge. This includes among others also short articles dealing with safety, such as for example the behaviour in the case of a fire as well as other topics of current interest. (c) Safety Brochure In Hamburg a safety brochure is published which informs all passengers about safety equipment that are available in the trains and at the stations. So for example, guidelines are given of how to employ fire extinguishers and where to obtain further information. The brochure is very well accepted among the passengers. (d) Information of Elderly Persons Three to four years ago, Hamburg began to invite people living in old people's homes to come and visit public transport companies. The elderly people were taken immediately to the spot, that is they were not only taken to the headquarters or the central control station, but also to the stations themselves. There the respective installations were explained to them. This procedure proved to be very efficient. The elderly people sent in thank-you-letters and expressed their appreciation. They were surprised at the safety measures employed in the subway and in local traffic and felt much safer after visiting the public transport companies.
Cologne and Düsseldorf very deliberately approach elderly citizens. The intention is to explain very cautiously and politely and with the necessary care what they have to do in an emergency case. During these events, topics such as "How can I leave the subway, if the train stops?", "How do I activate modern facilities such as elevators leading to the stations?" or "How do I avoid panic?" are discussed. (e) Information for School Children In Hanover an information programme was installed for school classes (2nd and 3rd class) which is very well accepted among school children. In many cases, there are lots of advance reservations made for these events. Here, the children are taught which are the dangers in subway traffic, which is the correct way to behave – as for example not jumping off the train, moving properly and according to the rules – and safety advices. (f) Built-in Multimedia Readout System in the Vehicles Multimedia systems are already employed, so for example in Hamburg in the DT4 vehicles. These are monitors which display above all advertisements but also information on the company and safety advice. (g) Display Systems in Stations
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In the case of a fire, the right information is given to the passengers in the right moment – this needs to be guaranteed. False information can generate disasters. (h) New Communication Facilities New communication facilities in public transport are still in an early development phase. The communication facilities available today are not yet sufficiently used, which is also due to the fact that it is not yet known to which extent they are really accepted by the passengers. These facilities also entail consequences which nobody had expected, such as the dramatic reduction in the degree of vandalism since these "info-screens" were built into the trains.
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6. Proposal for EU guidelines
Comparing the collected data on best practices for incident detection systems, traffic management and user information and communication in tunnels in existing tunnels around Europe with the EU Directive on safety in tunnels some gaps have been identified. In the following lines some recommendations on how the EU Directive could be improved in order to increase safety in tunnels are proposed.
6.1 General recommendations
1. Responsible parties under the EU Directive should establish a “live” assessment committee based on a permanent working group.
2. Responsible parties under the EU Directive should be encouraged to reach the level of safety of the EU Directive in small tunnels with special characteristics, where applicable.
6.2 Incident detection systems and methods
1. Tunnel designers and authorities should establish an Incident and fire detection systems database.
2. Tunnel authorities should provide an evaluation of the different incident and fire detection systems compatibility.
3. Tunnel authorities should consider communication such as voice communication between control centre operators and motorists.
6.3 Traffic management methods
1. All the responsible parties under the EU Directive should provide more precise parameters or methods on how to make a decision about the number of tubes and lanes.
2. All the responsible parties under the EU Directive should define a minimum lane width and cross-sectional geometry.
3. All the responsible parties under the EU Directive should define a maximum and minimum of the transverse gradient.
4. All the responsible parties under the EU Directive should be more specific in the design of road marking elements.
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5. The Directive should be more precisely on how to evaluate the effectiveness of lay-bys for existing tunnels.
6. The EU Directive should list parameters which help to make a decision concerning the usefulness of separate truck lanes.
7. The EU Directive should be more specific about parameters like speed, location and percentage of HGV when planning traffic management equipment.
8. The EU Directive should standardize the minimum equipment for traffic management.
6.4 User information and communication
1. The lighting level in the transient area should be according to light conditions outside, so that the lighting level should be adjustable and differ between daytime and nigh time conditions.
2. The training and equipping of emergency services should be specified how often they should be done (Link to Article 4.6)
3. The operator should have access to pre-recorded messages, bilingual if applicable and one in English.
4. All the responsible parties under the EU Directive should describe short messages for accidents, with clear statements.
5. All member states of the EU Directive should be encouraged to have certification processes for tunnels with its correspondent inspectors. (link to article 7)
6. All member states of the EU Directive should include specific requirements for combi tunnels.
7. All member states of the EU Directive should provide additional and reinforced measures to ensure safety, in case that emergency walkways are not applicable. (Link to the 2.3.1 Directive)
8. All member states of the EU Directive are encouraged to provide specifications about the design (colour, form, lighting…) of the emergency escape door. (Link to the 2.3.9 Directive)
9. All member states of the EU Directive should consider physical barriers application in order to close the tunnel after consultation with emergency services (Link to the 2.15.1. Directive)
10. All member states of the EU Directive should consider sound beacons in the tunnels for indicating emergency exists. (Link to the 2.15.1 Directive)
11. All member states of the EU Directive should be more specific in the information stated for appropriate speeds and distance. (Link to the Article 3.9)
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12. All member states of the EU Directive should include co-operation between different emergency rescue services (medical, personnel, fire brigades, police) in the full scale exercise. (Link to the point 5 in Annex II)
13. All member states of the EU Directive should be encouraged to include behavioural messages for RDS codes.
14. All member states of the EU Directive should be encouraged to transmit each frequency to a break system in a tunnel and the possibility to give a vocal message.
15. All member states of the EU Directive should encourage users not to use the mobile phones in case of incident/accident inside a tunnel and add a parallel system of communication for all the emergency services.
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7. Limitations
As it has been mentioned before, this WP deals with only one of the parts that integrate the safety chain in a tunnel. The analysed documents are mostly a compendium of the standards and guidelines that are used to develop tunnel incident management systems and actual experiences with existing systems in the respective countries and /or cases, incident management systems currently being used for single and multiple tube tunnels with uni-directional and bi-directional traffic flow on motorways. This WP reviews incident detection, traffic management and user information methods.
In order to have more valuable results in the establishment of recommendations information on best practices and last technological developments has been asked to be provided by other members in the consortium. Not a significant response has been obtained as most of the European countries work under the same requirements, established by EU Directive or in some cases using other countries regulations, more restrictive than the ones from each country. This is the case of Spain, where regulation applying safety in tunnels is very poor and for the engineering projects it is used the Directive and the French regulation.
Therefore, the evaluation of the different systems and methods is quite subjective in the sense that actual incident detection procedures and guidelines, traffic management and user information are different for each tunnel and need to be developed by the authority responsible for the operation of the tunnels and the safety of the personnel using the tunnel. For this, human factors must be reviewed along with the hardware devices, the traffic management methods and the user information and communication systems discussed in this Work Package for each individual case.
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8. Recommendations
For future work a more detailed analysis taking into account cost effectiveness, user acceptance and friendliness for the operator, response time, etc. should be realized in order to have more feasible criteria for evaluation.
Due to lack of time and resources this evaluation has not been able to be carried as it was planned.
Higher compromise from other partners (countries) involved in the project would have been necessary and good for the project result.
Nevertheless, at this stage of the project we consider that SafeT network has done a very important and useful work which will result in an improvement of safety in tunnels around Europe. We consider that SafeT network or a similar consortium where different agents of all parts of the safety chain and international organisms discuss together the best practices and new technological developments and adaptations to establish recommendations should be kept in order to update the information here presented which is continuously changing. EU Directive should be a “live” document opened to changes.
Apart from the global recommendations here presented, dynamic recommendation adapted to each case must be established by the authorities responsible of the tunnels.
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9. References
[1] WP3 Report: Fire safe Design, Road Tunnels, Public Draft document, FIT European Thematic Network, September 2003, available at http://www.etnfit.net [2] Best Practice Manual on Operation and Maintenance of Tunnels, PIARC C5: Road tunnel operation, Working group 1: Operations, December 2003 [3] Tunnel standard description, SICE: internal document [4] Proposal for a Directive of the European Parliament and of the council on minimum safety requirements for tunnels in the Trans-European Road Network, European Commission, December 2002 [5] Integral Unification of tunnels monitoring, paper 2211, Lorenzo Espinosa Román, Proceedings of the 10th World Congress on Intelligent Transportation Systems and Services , November 2003, Madrid [6] Túneles: equipamiento y seguridad, Extraordinario 2000 Túneles, Revista Carreteras. [7] Seguridad en los túneles de carreteras, RACE/RACC, Seguritecnia, Septiembre 2001 [8] La seguridad en los túneles y el factor humano, Rafael López Guarga, Revista Rutas [9] El transporte de mercancías peligrosas a través de los túneles de carretera, Resumen del proyecto de investigación conjunta OCDE, PIARC, Jesús Leal Bermejo et al, Revista Rutas [10]“Traffic Incident Management systems used in road tunnels”, October 2002 , PIARC Road tunnels Committee-working Group 4- communications systems and geometry [11] SafeT Proposal, www.safetunnel.net [12]Directive 2004/54/EC of the European Parliament and of the Council of 29 April 2004 on minimum safety requirements for tunnels in the trans-European road network, Official Journal of the European Union [13] RABT 2003, Richtlinien für die Ausstattung und den Betrieb von Straßentunneln, Forschungsgesellschaft für Straßen- und Verkehrswesen [14]Road Tunnel Equipment – Technical Specification, Ministry of Transport of the Czech Republic – Road Department [15]Tunsafe Leaflet [16]www.are.admin.ch [17]www.gotthard-strassentunnel.ch [18]www.benefitcost.its.dot.gov [19]Ayres T.J., Wood C.T., Schmidt R.A. & McCarthy R.L. (1998) Risk Perception and Behavioral Choice. In: M. R. Lehto (Ed.). Hazard Communication. Mahwah: LEA, 35-52 [20]Boer, L.C. (1998) Improved Signposting for the Evacuation of Passenger Ships (Report TNO 1998 C 081) Soesterberg: TNO Human Factors, the Netherlands. [21]Boer, L.C. (2002) Behaviour by motorists on evacuation of a tunnel (Report TM-02-C034). Soesterberg: TNO Human Factors, the Netherlands. [22]Boer, L.C. & Varkevisser, J. (2002) Lijnverlichting op de vluchtroute in tunnels [Glow cable as escape lighting in tunnels] (Report TNO TM - 01 - C016). Soesterberg: TNO Human Factors, the Netherlands. [23]Boer, L.C. & Vredeveldt, A, (1999) Trouver son chemin: comportement des passagers et systèmes de guidages [Way-finding behaviour and technical guidance systems]. Revue Navigation, 1999, vol 47, no 188, p 428-439. [24]Boer, L.C. & Withington, D.J. (2004) Auditory guidance in a Smoke-filled Tunnel. Ergonomics, 47, 1131-1140.
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[25]Canter, D. (1990) Fires and Human Behaviour, 2nd edition, pub. David Fulton, London. [26]CIE (1990) Guide for Lighting of Road Tunnels and Underpasses. Publication CIE 88-1990. Vienna, Austria: Commission Internationale de l’Eclairage. [27]Edworthy, J (1998)Warnings and hazards: An integrative approach to warnings research. International Journal of Cognitive Ergonomics, 2, pp. 3-18. [28]Gibson J.J. (1979) The Ecological Approach to Visual Perception. Boston: Houghton Mifflin Comp. [29]Lehto M.R. (1998). Foreward: Special Issue on Hazard Communication. In: M. R. Lehto (Ed.). Hazard Communication. Mahwah: LEA, 1-2. [30]Martens, M.H. (Ed.) (2004) Human Factors Aspects in Tunnels: Tunnel User Behaviour and Tunnel Operators. Deliverable 3.3, UPTUN project. UPgrading of existing TUNnels. Project No: GRD1-2001-40739 (www.uptun.net). [31]Martens, M.H., Koster E.R. & Lourens, P. (1998) Westerscheldetunnel: Verkeersveiligheid tijdens calamiteiten met evacuatie [Westerschelde tunnel: Traffic safety during calamities with evacuation] (Report 1998 C 033) Soesterberg: TNO Human Factors, the Netherlands. [32]Proulx G et al (1999), Assessment of photoluminescent material during office occupant evacuation, Internal Report 774. Ottawa (CA): Institute for Research in Construction, National Research Council [33]Schreuder, D.A (1964) The Lighting of Vehicular Traffic Tunnels. Centrex Eindhoven, The Netherlands. [34]Schreuder, D.A. (1996) Lighting for Safety [Openbare verlichting voor verkeer en veiligheid). London, UK: Thomas Telford [35]Steyvers, F. J. J. M., de Waard, D., & Brookhuis, K. A. (1999). Aspects of human behaviour in tunnel fires – a literature review International Tunnel Fire & Safety Conference, Rotterdam 1999 [36] Road Tunnels Manual. Norwegian Public Roads Administration website.
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