Critical Aspects of Planning, Design and Operation of High Speed Roads

CRITICAL ASPECTS OF PLANNING, DESIGN AND OPERATION OF HIGH SPEED ROADS

Dr. T S Reddy LEA Associates South Asia Pvt Ltd., New Delhi [email protected]

ABSTRACT High Speed Roads are the major contributors to the mobility and thus link the major centers separated over long distances. These roads account for more than 50 percent of the vehicle kilometers travelled in any country and more so in India. Normally these high speed roads will have limited and restricted access and operate at high speeds. Access to these roads is normally through properly planned and designed interchanges provided with appropriate speed change lanes merging in to or diverging from the carriageway of the high speed roads. At present there are a few of these roads in the form of Expressways and National Highways in India. Expressways are mainly fully access controlled and the National Highways are partially access controlled. These facilities are designed to operate at 120 kmph but due to the problems related to cost and land acquisition safety aspects are compromised in planning and design. As a result these high speed roads are becoming potential contributors to serious and fatal accidents. Recent accident statistics indicate the rising trends of fatalities and serious injuries on National Highways. This paper tries focus on some important safety features that need to be considered at planning, design and operation stages for improved safety on these roads. The paper is intended to illustrate these features and the impact of their absence on safety of users and non-users of high speed roads in India. Often road side environment is ignored or overlooked at the time of planning the high speed roads in India. Besides this impacts of severance and need for speed change lanes to effect smooth transition in speeds from/to high speed roads are ignored. Many of the interchanges are provided with improper geometrics for slip and loop roads. Fixed and rigid objects on road side are left unprotected leading to severe accidents. Inadequately conceived and designed signs and markings create avoidable confusion in communication with the road users.

KEY WORDS Planning, Design, Operation, High Speed Roads 1. INTRODUCTION High speed roads are meant for moving over long distances in shorter time. These roads are called by different names in different countries. They are called Freeways in the USA, Motorways in the UK , Auto-Bohns in Germany, Expressways in Japan. In India we have very little proportion of such roads by length. However the efforts of National Highways Authority of India (NHAI) have been to create a network of National Highways under National Highway Development Programme (NHDP) with little or no access control. At present merely less than 2 percent of the National Highways in length carry more than 60 percent of the vehicle kilometers in India. Annually about 150 thousand fatalities are reported in India from Road Traffic Accidents.The share of NHs is 35 percent of the fatalities in India. In other words on an average there is more than 500 deaths per 1000 kilometers annually. Most of these deaths/accidents are 2

attributable to the inadequacies in planning, design, and operations of the highways. In this paper an attempt is made to highlight very important and critical features relating to planning, design and operation of the highway that can significantly influence the occurrence and severity of the accidents on the National Highways of India. 2. SEVERANCE OF COMMUNITIES It is very common that along the alignment of high speed roads the road side communities will be physically separated by the roads passing through them. Therefore at the planning stage these aspects must be considered and appropriate facilities to maintain the connectivity should be provided. Otherwise the high speed road will be creating death traps in the community. Below photo graphs illustrate a case where an existing road in a community is severed by high speed road and the resulting problems faced by the community.

People living on both sides cross the bypass carrying high speed traffic by climbing the embankment and carrying their cycles risking their lives.

3. ROADSIDE OBJECTS On high speed roads the chances of vehicles straying on account of fatigue, inattentiveness of the drivers is very likely and their crashing into any fixed and rigid objects on the road side is going to be highly damaging. Therefore it is essential that these objects must be shielded with impact absorbing materials like W-Beams, Rubber cushions. Below photographs show the accidents that have occurred because of such situations.

To prevent such accidents installation of W-Beam or Tactile Barriers will be useful.

4. MERGING AND DIVERGING AREAS On high speed roads merging into the stream or diverging to go out of the stream at interchange points is very critical from the safety point of view. In majority of the high speed roads in India this aspect is ignored, probably because of ignorance of safety issues resulting in serious accidents. Below given in photos are example from Indian high speed roads.

A couple of good examples from japan and South-Africa are given in the Photographs below

5. SERVICE AREAS Service areas are very critical from safety point of view because these will be reduction in speed of the vehicles going into service areas from the high speed roads. Service areas must be properly located, planned and designed to ensure safety on high speed roads. Below photos illustrate the inadequacies of the designs along some of the highways in India.

6. COMMUNICATION WITH ROAD USER Signs must be so designed to satisfy three-Cs as indicated below C-Catch the eye C-Convey the message and C-Command respect

The size of the legends and signs must be commensurate with the design speed of the road. As far as possible long messages and unconventional legends must be avoided. This will ensure uniform understanding of the meaning of the signs and increase their compliance. Below illustrated are some of the ineffective and ambiguous signs installed on high speed roads. On Mumbai Pune Expressway sign indicates directions in an incomplete manner.Mumbai should be appearing on both segments of the board because those who do not want to use the toll road must be given the information that the other road also leads you to Mumbai.In one sgn very lengthy message is written to inform that two wheeler and three wheelers are not allowed on Expressway.Better way of showing directions on high speed roads is through installation of map type signs as shown in the example on a regional road in South Africa. 6

7. SIDE SLOPES AND DRAINS In designing the slide slopes and drains along the alignment proper care is to be exercised. As far as possible the side slopes should be drivable with maximum of 1:4 vertical to horizontal and side drains must be shielded or covered with proper covers of adequate strength.Below photographs show the impending danger of steep side slopes and deep open drains.

8.NARROW SHOULDERS Shoulders less than 3 meters make the avenue for the vehicles to wait on them with part occupation of travelled lane resulting in rear end collisions as shown in photographs below.

9. FIXED OBJECTS IN TRAVELLED WAY In many situations, particularly at the approaches to flyovers and pedestrian under-passes parapets stand in the carriageway causing sudden surprises to the drivers. Unless these are avoided or properly delineated and traffic guided effectively to negotiate through these locations serious accidents are inevitable. Below photographs show examples of such accidents.

10. LOCATION OF ENTRIES AND EXITS On high speed roads entries and exits location should be given due consideration because of the speed reductions to be achieved at the exits and acceleration to be achieved at the entries to merge safely in to the traffic stream moving at high speed. Below shown are some examples of incorrect location of entry and exit on Mumbai-Pune Expressway. Entry and Exits are located at the apex of the curve.These locations are highly prone for accidents.

11. SUMMARY In the foregoing sections an attempt is made to illustrate a few of the important aspects needing attention of the planning, design and operation personnel of high speed roads. To sum up the following aspects need utmost attention of the high speed owners and operators.

 Severance of Communities: Care should be taken to ensure the provision of appropriate interaction channels between communities  Roadside Objects: Care should be taken to delineate fixed objects and protect the straying vehicles from hitting the fixed rigid objects.  Merging and Diverging Areas: Speed change lanes and appropriate lane balancing must be ensured for smooth and safe merging and diverging operations. Delineation of gore areas must be adequate to guide the drivers.  Service Areas: Entry and Exit into service areas and their presence must be clearly visible and the operations must be obvious to the users of high speed roads.  Communication with Road User: Appropriate size and legends of the signs along with colours must be ensured to communicate the messages in time to the users of high speed roads.  Side Slopes and Drains: Care should be taken to provide drivable slopes where ever possible. Otherwise the protection must be made from running the vehicles off the roadway.  Narrow Shoulders: Narrow shoulders should be avoided on high speed roads as they are likely to cause rear end collisions.  Fixed Objects in Travelled Way: As far as possible surprises by way of parapet wall ends and fixed poles and pillars must be avoided. If they are present they should be protected and traffic should be properly regulated by delineation and diversions.  Location of Entries and Exits: The entry and exits should be located invariably on straight sections and not on curves and blind corners. ACKNOWLEDGEMENTS The examples presented in this paper were gathered during various phases of the author working at CRRI, NewDelhi and with LEA Associates South Asia Pvt Ltd,. The author gratefully records the opportunities provided by the CRRI and LASA. He also acknowledges the association of many of his colleagues both at CRRI and LASA in learning many aspects relating to Road Safety.