TRAFFIC SAFETY SYSTEMS

GUIDANCE

Picture updated December 2018

March 2019

TRAFFIC SAFETY SYSTEMS GUIDANCE 2 0 3-2019

FOREWORD

This guidance was prepared by the Division of Traffic Operations to establish uniform practices and guidance for the traffic safety systems of the Department. This guidance does not constitute a standard, specification or regulation. Field and economic conditions may call for variation from this guidance’s requirements and may be subject to approval by designated levels of management in the district or at Headquarters. This guidance is neither a textbook nor a substitute for engineering knowledge, experience or judgment. It includes techniques as well as graphs and tables not ordinarily found in textbooks. These techniques are intended as aids in the solution of field conditions.

TRAFFIC SAFETY SYSTEMS GUIDANCE 3 0 3-2019

TABLE OF CONTENTS

Topic No. Subject Page No. Date

1 GENERAL INFORMATION AND STANDARDS 6 1.1 Introduction 6 06-01-2017 1.2 Roles and Responsibilities 6 06-01-2017 1.3 Traffic Safety System Standards 7 06-01-2017 1.4 Traffic Safety Systems Designs and National & 7 06-01-2017 Traffic Safety System Crash Testing Guidelines

2 CLEAR RECOVERY ZONE CONCEPT 12 2.1 Introduction 12 06-01-2017 2.2 Remove/Relocate the Fixed Object 12 06-01-2017 2.3 Make the Fixed Object Breakaway 12 06-01-2017 2.4 Shield the Fixed Object 13 06-01-2017 2.5 Delineate the Fixed Object 13 06-01-2017

3 GUARDRAIL 14 3.1 Introduction 14 06-01-2017 3.2 Guardrail Types 14 06-01-2017 3.3 Guardrail Installation Criteria 16 06-01-2017 3.4 Guardrail at Embankment Slopes 16 06-01-2017 3.5 Guardrail at Fixed Objects 17 06-01-2017 3.6 Guardrail Design Considerations 20 06-01-2017

4 MEDIAN BARRIER 48 4.1 Purpose 48 06-01-2017 4.2 Function 48 06-01-2017 4.3 Barrier Types 48 06-01-2017 4.4 Study Warrants 48 06-01-2017 4.5 Criteria for Choice of Type 51 06-01-2017 4.6 Barrier Design Details 53 06-01-2017 4.7 Median Design Considerations 54 06-01-2017 4.8 CHP Enforcement Areas / Emergency Passage- 59 06-01-2017 ways 4.9 Glare Screens 59 06-01-2017 4.10 Delineation 60 06-01-2017

5 OUTER SEPARATION BARRIER 60 5.1 Introduction 60 06-01-2017 5.2 Outer Separation Barrier Criteria 60 06-01-2017 TRAFFIC SAFETY SYSTEMS GUIDANCE 4 0 3-2019 TABLE OF CONTENTS (continued) Topic No. Subject Page No. Date

6 CRASH CUSHIONS 61 6.1 Purpose 61 06-01-2017 6.2 Available Crash Cushion Types 61 06-01-2017 6.3 Placement 61 06-01-2017 6.4 Temporary Crash Cushions 61 06-01-2017 6.5 Severe Duty Crash Cushions 61 06-01-2017

APPENDIX 63 A Exception to Traffic Safety System Standards 63 01-05-2012

LIST OF FIGURES

Figure No. Title Page No. Date

1 Block-out with Steel Post 15 06-01-2017 2 Equal Severity Curve 18 01-05-2012 3 Railing at Fixed Objects or Embankment Instal- 18 09-01-2015 lations 4 Railing at Structures 23 09-01-2015 5a Position of Guardrail at Fixed Objects 24 06-01-2017 5b Length of Need Determination 25 06-01-2017 6a Metal Beam Guardrail Connection to 26 09-01-2015 6b Metal Beam Guardrail Connections to Anchor 27 02-10-2014 Posts 7 Post Embedment in Rock 28 06-01-2017 8 Guardrail 29 06-01-2017 9a W-Beam near Cut Slopes 31 06-01-2017 9b MGS Typical Layout for Cut Slopes and Termi- 30 06-01-2017 nal System End 10 Guardrail on Standard and Narrow Embank- 37 06-01-2017 ments 11 Guardrail Concrete Beam on Narrow Embank- 38 09-01-2016 ments 12a Long Span Midwest Guardrail System 39 06-01-2017 12b Long Span Nested MBGR 40 09-01-2015 13 Special Post Footing Detail 41 09-01-2015 14a Adjustable Height W-beam (2 Hole Post) 42 06-01-2016 14b Adjustable Height W-beam (3 Hole Post) 43 09-01-2015 15 Midwest Guardrail Shift Post Detail 44 06-01-2017 TRAFFIC SAFETY SYSTEMS GUIDANCE 5 0 3-2019

LIST OF FIGURES (continued)

16 Multiple Block-Out Details for MGS 45 06-01-2016 17 MGS Transition Detail for 27 ¾” Median Crash 46 06-01-2017 Cushion to Double Midwest Guardrail Systems 18 W-beam Height Measurement 47 06-01-2017 19 Freeway Median Barrier Study Warrant 49 06-01-2017 20 Thrie Beam Barrier Rub Rail Detail 57 09-01-2016 21 Thrie Beam Connection to Bridge Curbs 58 09-01-2016 22 Sand Barrel Arrays 62 09-01-2016

LIST OF TABLES Table No. Title Page No. Date

1 Crash Test Levels 9 06-01-2017 2 Standards Requiring Headquarters Approval for 9 06-01-2017 Exceptions 3 Standards Requiring District Approval for Ex- 10 06-01-2017 ceptions 4 Procedural Standards 11 06-01-2017 5 Commonly Placed Fixed Objects 13 09-01-2015 6 Railing and Barrier Restoration Practice 35 06-01-2017 7 Median Barrier Type Selection Table 51 06-01-2017

TRAFFIC SAFETY SYSTEMS GUIDANCE 6 0 3-2019

Topic 1 – General Information and traffic safety systems and makes recommenda- tions for exceptions to Traffic Safety System Standards Standards that require District and Headquar- ters approval. 1.1 Introduction 3. District Traffic Safety Engineer: The District Traffic Safety Engineer, or their designee, en- Traffic safety systems are features de- sures compliance with the traffic safety systems signed primarily to reduce the severity of run-off- policies in this guidance. The engineer recom- collisions, prevent errant from cross- mends exceptions to traffic safety system ing the median, and decelerate errant vehicles. standards that require Headquarters approval, These features include, but are not limited to, and approves exceptions to the traffic safety guardrail, crash cushions, median barrier, end treat- system standards that require district approval. ments, breakaway supports for signs and light 4. Deputy District Director of Traffic Operations: standards, and truck escape ramps. (For more infor- The Deputy District Director of Traffic Opera- mation about the design of truck escape ramp facil- tions, or their designee, along with the Deputy ities, see Traffic Bulletin No. 24 and NCHRP Re- District Director of Maintenance, approves the port 178.) use of cable guardrail and cable median barrier. 5. Deputy District Director of Maintenance: The 1.2 Roles and Responsibilities Deputy District Director of Maintenance, or their designee, along with the Deputy District The District Traffic Safety Office or District Director of Traffic Operations approves the use Traffic Operations Office is the primary district of cable guardrail and cable median barrier. functional unit responsible for the application of 6. Headquarters Traffic Safety Systems Branch, standards and policies for use of traffic safety sys- Chief: The Headquarters Traffic Safety Sys- tems on State highways. The Headquarters Office tems Branch Chief, or their designee, advises of Traffic Engineering ensures quality control of on the use of traffic safety systems and is the those standards and policies, and the Headquarters first contact in Headquarters Division of Traffic Traffic Safety Systems Branch, Chief has authority Operations for inquiries from district person- over certain standards. The Division of Mainte- nel. The Headquarters Traffic Safety Systems nance ensures the most efficient use of personnel Branch Chief approves exceptions to the traffic and materials resources for those applications. The safety system standards that require Headquar- Project Engineer signs and stamps the project plans ters approval. Also, approves the exceptions for and is responsible for the selection and placement the use of concrete guardrail where the criteria of traffic safety systems used in the project. in Topic 3.2(2) are not met. 7. District Maintenance Engineer: The District The following establishes the role and respon- Maintenance Engineer is consulted regarding sibility of Headquarters or district personnel in- use of thrie beam barrier as outlined in Table 7. volved in decisions regarding installation or up- 8. Construction Engineer: The Construction En- grade of traffic safety systems. gineer inspects and oversees the placement of traffic safety systems within a construction pro- 1. Project Engineer: The Project Engineer speci- ject and ensures that they are in compliance fies traffic safety systems and shows their with the project plans, the Standard Plans, non- placement on the project plans. The engineer standard special provisions, and the policies coordinates with the District Traffic Safety Of- contained within traffic safety systems guid- fice/Branch to complete the Exceptions to Traf- ance. The construction engineer coordinates fic Safety System Standards form, see Appendix with the District Traffic Safety Systems Branch A. and the project engineer on the placement of 2. District Traffic Safety Systems Coordinator: these systems and the need for field changes to The District Traffic Safety Systems Coordina- the plans concerning changes and installation tor is the primary contact for inquiries about of traffic safety systems. traffic safety systems in the respective districts. The coordinator provides guidance for use of TRAFFIC SAFETY SYSTEMS GUIDANCE 7 0 3-2019 1.3 Traffic Safety System Standards and Summary of Quantities, and may ad- dress applicable Layout Sheets. This section identifies the traffic safety system • Topic 3.5: A statement of concurrence that standards which are defined and implemented as addresses all locations in the Project Plans, follows: Headquarters Approval Required: Statements as indicated in the Summary of Quantities, of required practice that are considered the most es- and may address applicable Layout Sheets. sential are traffic safety system standards that use • Topic 3.6: A statement of concurrence that the word “shall” and are printed in boldface type. addresses all locations in the Project Plans, Deviations from those standards are approved by as indicated in the Typical Cross Sections the Headquarters Traffic Safety Systems Branch and Summary of Quantities, and may ad- Chief, documentation requirements for the ap- dress applicable Layout Sheets. proval process for exceptions to traffic safety sys- tem standards requiring Headquarters approval is in • Topic 6.3: A statement of concurrence that the appendix, and the editable format is posted on addresses all locations in the Summary of the Division of Traffic Operations, Office of Traffic Quantities, and may address applicable Engineering, Traffic Safety Systems Branch web Layout Sheets. site. See Table 2 for the list of Traffic Safety Sys- For the above topics, copies of the identified tem Standards that require Headquarters approval Project Plans Sheets may supplement the docu- for exceptions. mented statements of concurrence inserted in the District Approval Required: Statements of rec- project files. See Table 4 for the list of procedural ommended, but not essential practice in typical sit- traffic safety system requirements. uations, with deviations allowed if engineering Permissive Traffic Safety System Standards: judgment or engineering study indicates the devia- Permissive Traffic Safety System Standards are tion to be appropriate, are Traffic Safety System statements of practice that are permissive condi- Standards that appear in underlined type. The verb tions and carry no requirements or recommenda- “should” is typically used. Deviations from those tions. Permissive statements texts appear in normal standards are approved by the District Traffic type. The verb “may” is typically used for permis- Safety Engineer. The documentation requirements sive Traffic Safety System Standards. for the approval process for exceptions to Traffic Safety System Standards requiring District ap- 1.4 Traffic Safety System Designs and proval is in the appendix, and the editable format is National Traffic Safety System Crash posted on the Division of Traffic Operations, Office of Traffic Engineering, Traffic Safety Systems Testing Guidelines Branch web site. See Table 3 for the list of traffic safety system standards that require District ap- This topic discusses the use of Caltrans ap- proval for exceptions. proved traffic safety system designs and provides Procedural Traffic Safety System Require- an overview of the national traffic safety systems ments: Procedures required for the use of traffic crash testing guidelines that are the basis for the de- safety systems are indicated by the word “must” signs. These designs are based on full-scale crash and are enclosed with boxes in the text. The proce- test and are conducted under controlled conditions generally associated with typical highway features. dures may involve actions by the Headquarters It also addresses upgrading traffic safety systems in Traffic Safety Systems Branch Chief and/or the projects other than projects programmed in the Col- District Traffic Safety Engineer, along with the Dis- lision Reduction Category of the State Highway trict Maintenance Engineer, or the Deputy District Operation and Protection Program (SHOPP). Directors for Traffic Operations and Maintenance.

Where documentation in the project files is re- 1. Standard Designs: The Standard Plans contain quired, the district may determine its type. Guid- design details for the construction of some non- ance for documentation requirements in 3 and 6, ex- proprietary traffic safety systems. Standard cept Topics 3.2, 3.6(2) and 3.6(6), is provided be- Plans cannot always be directly applied to all low. situations on existing roadways, and some de- • Topic 3.4: A statement of concurrence that sign modifications may be needed. Modified or addresses all locations in the Project Plans, unique non-proprietary traffic safety system as indicated in the Typical Cross Sections TRAFFIC SAFETY SYSTEMS GUIDANCE 8 0 3-2019 designs require review and approval of a Head- new or modified safety features. (See Table 1, quarters Traffic Safety Systems Branch Chief. Crash Test Levels). In accordance with the All approved traffic safety systems are listed on MASH Implementation memo, once a large the Department’s Pre-Qualified Products List enough section of the existing system is dam- (Authorized Materials List) for Highway aged and requires a project to replace the sys- Safety Features and available from the Traffic tem, only Caltrans approved MASH safety sys- Safety Systems Coordinator. tems will be allowed on California State High- 2. Overview of Crash Testing Guidelines: The De- ways. partment has adopted the Manual for Assessing 3. Upgrading Traffic Safety Systems: Standards Safety Hardware (MASH), which was pub- for traffic safety systems have evolved over lished by the American Association of State time and continue to change in response to Highway and Transportation Officials changing technology, research findings, and (AASHTO). The MASH Implementation changes in the design and speed of vehicles. memo, dated December 23, 2016, lists the se - Consequently, some existing traffic safety sys- quence of dates that MASH safety devices will tems may not comply with the latest adopted take effect. Full MASH compliance will be crash testing guidelines. It is often neither eco- achieved by October 31, 2019. In MASH, pro- nomically feasible nor practical to upgrade ex- cedures are presented for conducting isting installations when revisions are made to crash tests and in-service evaluation of roadside current crash testing guidelines. safety features or appurtenances. The proce- When major work is done in a project, dures are directed toward the safety perfor- which is funded by STIP, Local Agencies, mance of roadside safety features; other service Propositions, Federal Government, SHOPP Re- requirements such as economics and aesthetics surfacing, Restoration & Rehabilitation (2R), are not considered. or Assets Management (Multi Assets Projects), The crash testing procedures are devised to traffic safety systems must be upgraded to cur- subject roadside safety features to severe vehi- rent standards. With other SHOPP programs, cle impact conditions rather than to typical or upgrading to current standards should be done average highway situations. For vehicle crash provided that SHOPP program guidelines al- testing, specific impact conditions are pre- low it. sented for vehicle mass, speed, approach angle and critical impact point on the safety feature. The crash test results are based on frontal im- pacts of vehicles; the crash testing criteria do not include side or rear impacts by vehicles. Three primary appraisal factors are presented for evaluating the crash test performance: struc- tural adequacy, occupant risk and after-colli- sion vehicle trajectory. MASH updates the guidelines for in-ser- vice evaluations provided in NCHRP Report 350, which became effective October 1, 1998. MASH recognizes the complex nature of vehic- ular collisions and the limited resources of agencies responsible for monitoring the performance of

TRAFFIC SAFETY SYSTEMS GUIDANCE 9 0 3-2019 Table 1: Crash Test Levels

TEST TEST VEHICLE DESIGNATION AND TYPE TEST CONDTIONS LEVEL MASH NCHRP Report 350 SPEED ANGLE (MPH) (degrees)

1100C (Passenger Car) 820C (Passenger Car) 44 25 2 2270P (Pickup Truck 700C (Passenger Car) 44 25 2000P (Passenger Car 44 25

1100C (Passenger Car) 820C (Passenger Car) 62 25 3 2270P (Pickup Truck) 700C (Passenger Car) 62 25 2000P (Passenger Car) 62 25

1100C (Passenger Car) 820C (Passenger Car) 62 25 4 2270P (Pickup Truck) 700C (Passenger Car) 62 25 10000S (Single Unit Truck) 2000P (Passenger Car) 56 15 8000S (Single Unit Truck) 56 15

Table 2 Standards Requiring Headquarters Approval for Exceptions

Topic 3 Guardrail 3.6(10)(l) and Dike in front of Guardrail Index 3.2(2) Concrete Guardrail Offset 3.6(11) Offsetting and Overlapping Guard- 3.5 Strengthened Guardrail rail 3.5 Guardrail at Fixed Objects Topic 04 Median Barrier 3.6(1) Breakaway Anchors Index 4.5(1) Concrete Barrier 3.6(3) Mountable Dike 4.5(2) Thrie Beam Barrier 3.6(3) Curb and Dike with MGS with 8- 4.5(2) Thrie Beam Barrier Maintenance inch Blockouts or MBGR Offset 3.6(4) Cross Slopes 10:1 or Flatter 4.6(2) Thrie Beam Barrier Saw-Toothed 3.6(7) Guardrail in Cut Slpos Median Section 3.6(8) Anchored to Pavement 4.7(1) Longitudinal Median Dikes 3.6(8) Anchored to Structures 4.7(6) Planted Medians 3.6(8)(c) Transitions to Structures 4.7(11) Pavement Overlays 3.6(10)(b) Consecutive Post 4.8(3) Access Opening Intervals 3.6(10)(c) Special Post Footing Topic 5 Outer Separation Barrier 3.6(10)(d) Adjusting Rail Height Index 5.2 Outer Separation Barrier Criteria 3.6(10)(g) Weathered W-Beam Treatment

TRAFFIC SAFETY SYSTEMS GUIDANCE 10 0 3-2019

Table 3 Standards Requiring District Approval for Exceptions

Topic 2 Clear Recovery Zone Concept 3.6(10)(b) Multiple blocks Index 2.3 United States Postal Service Mail- Long Span Nested Guardrail (add boxes fig back in) Topic 3 Guardrail 3.6(10)(f) Guardrail Delineation 3.6(10)(h) Guardrail in Fire Prone Areas Index 3.2(1) MGS Guardrail Selection 3.6(10)(l) Pullouts Mixing Guardrail Post Types 3.6(11) Offsetting and Overlapping Guard- 3.2(2) Pavement Beyond Concrete Guard- rail rail

3.5 Continued Strengthened Railing Section at Columns Topic 4 Median Barrier Shielding of Trees Index 4.4 Freeway Traffic Volume/Width Shielding Median Structure Col- Study Warrant umns 4.4(1) New or Widening Free- Guardrail on Two- Highways ways Guardrail on Two-Way, Multi- 4.4(5) Incremental Improvements Lane Highways 3.6(1) Guardrail Minimum Length of 4.7(2) Median Ditches Need 4.7(3) Scuppers Guardrail Length of Need 4.7(4) Median Barriers on Raised Medi- 3.6(2) Transition Railing at structure ap- ans proaches or concrete barrier 4.7(5) Paving Flat Medians with Barriers 3.6(2)(a) Two-Way Conventional Highway 4.7(7) Future Construction with Concrete 3.6(2)(b) Multi-Lane Highway with Separate Median Barriers Structures 4.10 Delineation of Median Barriers 3.6(2)(c) Multi-Lane Freeways or Express- ways with Decked Medians Bridge with Wide Clear Width Topic 5 Outer Separation Barrier 3.6(3) Dike Flush with MGS Index 5.1 Outer Separation Barrier Consid- 3.6(6) W-Beam in Rock ered 3.6(8) Concrete Guardrail Support Pad Intermediate Guardrail Anchorages Topic 6 Crash Cushions Guardrail Anchorages Side Slope Index 6.2 Crash Cushion Evaluated 3.6(9) Gaps Between Guardrail Installa- 6.3 Crash Cushion Height tions 3.6(10)(a) Restricted Horizontal Clearance to Hinge Point

TRAFFIC SAFETY SYSTEMS GUIDANCE 11 0 3-2019

Table 4 Procedural Standards

Prohibited Procedural Standards Index 3.2(1) Vegetation Control Topic 3 Guardrail 3.2(2) Attachments on Concrete Guardrail 3.4 Guardrail at Embankment Slopes Index 3.2(1) Guardrail Post in Pavement 3.5 Guardrail at Fixed Object 3.2(2) Concrete Guardrail on Soil 3.6(1) Guardrail Length of Need 5 Concrete Guardrail Use 3.6(12) Deviation from Typical Layouts Topic 4 Median Barrier Index 4.5(1) Concrete Barrier as Retaining Topic 4 Median Barrier Walls or on Soil Index 4(1) Freeway Median Barrier 4.4(2) Expressway Median Barrier Documentation in Project Files Required 4.5(1) Aesthetic Treatments 4.5(1) Attachments on Concrete Barrier Topic 3 Guardrail 4.7(3) Scuppers in Median Barrier Index 3.6(4) Vehicle Trajectory and Guardrail 4.7(8) Median Barrier and Cross Slope 4.7(12) Wildlife Passageways Headquarters Traffic Safety Systems Branch 4.8 Barrier Openings Approval Required 4.9 Glare Screens Topic 3 Guardrail Topic 6 Crash Cushions Index 3.6(10)(a) MBGR use of Cast-In-Drilled-Hole Index 6.3 Crash Cushion Placement Piles MGS use of 8-foot wood or

9-foot steel post

3.6(10)(b) Special Post Footing Deputy District Directors of Traffic Operations Topic 4 Median Barrier and Maintenance Approvals Required

Topic 3 Guardrail 4.5 Modification of Barrier Type Se- lection Criteria Index 3.2(3) Cable Guardrail 4.5(4) Portable Concrete Barrier Topic 4 Median Barrier 4.6(2) Sawtooth Thrie Beam Barrier Index 4.5(3)

District Traffic Safety Engineer Concur/Ap- District Traffic Safety Engineer Approval proval and Documentation in the Project Files Required Required Topic 3 Guardrail Topic 3 Guardrail Index 3.2(2) Concrete Guardrail

TRAFFIC SAFETY SYSTEMS GUIDANCE 12 0 3-2019 Topic 2 – Clear Recovery Zone 3. Relocate the fixed object as far as possible from the traveled way to minimize its chances of be- Concept ing struck. Non-traversable ditches, drainage structures, columns, utility poles, and overhead sign structures may be handled by this method. 2.1 Introduction 4. Relocate a fixed object in the median or gore to a location beyond the right CRZ, thereby reduc- An area clear of fixed objects adjacent to the ing the risk of exposure to at least one direction traveled way is desirable to provide a clear recovery of travel. zone (CRZ) for vehicles that leave the traveled way. Thirty feet should be considered the minimum clear recovery zone where possible for freeways and 2.3 Make the Fixed Object Breakaway high-speed expressways. In accordance with MASH, high-speed is defined as operating speeds Fixed objects that cannot be moved out of the greater than 45 mph. CRZ should be considered for breakaway treat- On most conventional highways, a 30-foot ment. These include but are not limited to the fol- CRZ may be difficult to justify for engineering, en- lowing: vironmental or economic reasons. For these rea- sons, a minimum CRZ of 20 feet on conventional • light standards highways is advised. • ground-mounted sign supports Site-specific conditions such as volume, speed, • mailbox supports alignment, side slope, weather, and environmental • call boxes conditions need to be considered when determining • chain control signs the CRZ. Guidance can be found in the Caltrans Light standards are used with a three-point tri- Highway Design Manual, Topic 309.1, and the angular slip-base where breakaway treatment is Roadside Design Guide, Chapter 3, published by needed. The Standard Plans contain details for this AASHTO for more information on the CRZ and feature. All light standards located within the CRZ how it can vary depending upon the roadway align- are to have a slip-base except where there is high ment, side slope, and traffic volumes. potential for pedestrians to be struck by the falling The installation of new fixed objects within the light standard, or when there are conflicts with traf- CRZ is to be avoided whenever practical on all pro- fic. jects. Fixed objects located in the CRZ, in order of The laminated wood box beam is the standard preference, should be: breakaway support system for large ground- 1. Removed/relocated, or mounted signs. Intermediate size ground-mounted 2. Made breakaway, or signs may be mounted on dimensioned wood posts. 3. Shielded Any sign post 4 inches x 6 inches or larger is to be 4. Delineate the obstacle drilled to make it breakaway. Details for the size

and location of the holes are contained in the Stand- ard Plans. 2.2 Remove/Relocate the Fixed Object Small ground-mounted signs may be supported on dimensioned wood posts or approved commer- The options available to remove or relocate a cially available yielding steel supports. Contact fixed object are as follows: your District Traffic Safety Systems Coordinator 1. Remove the fixed object if practicable. for information regarding commercially available 2. Move the fixed object to a location that is less yielding steel supports. likely to be hit, such as up a slope or behind If non-proprietary supports are used, mailboxes guardrail or wall required for other reasons. A are to be mounted either on wood posts no larger fixed object placed at least 5 feet up a cut slope than a nominal 4 inches x 4 inches, considered the (measured vertically from the toe of slope at a maximum breakaway size, or a steel pipe no larger minimum 3:1 although 2:1 is preferred) is con- than a nominal 2 inches in diameter. Spacing be - sidered outside of the CRZ. See the California tween mailbox posts shall be at least ¾ the height MUTCD, Section 2A.19. of the post. Multiple mailboxes are not to be mounted on a longitudinal rail within the CRZ.

TRAFFIC SAFETY SYSTEMS GUIDANCE 13 0 3-2019 There is an approved commercially available yielding mailbox support system that will accom- modate up to four mailboxes. The steel mailboxes installed by the U.S. Postal Service should not be installed in the CRZ. For more information about mailbox support design and placement, see the OBSTACLES TRAFFIC BAR- Roadside Design Guide, Chapter 11, “Erecting WITHIN THE RIER Mailboxes on and Highways.” DESIGN

CRZ AS NOTED Call boxes and chain control signs on steel posts should be mounted on slip-bases, unless oth-

erwise shielded. Other features in the vicinity are Embankments, critical not to impede the function of the breakaway device Typically YES, and traversable, or adversely influence the vehicle response. consult with District non-recoverable Breakaway objects are not to be placed behind Traffic Safety embankments without guardrail or bridge rail. For more information about Engineer. run-out area. breakaway electrical devices and slip bases see the

Traffic Manual, Chapter 9.

At the time of publications, October 31, 2019, Typically YES, when all bridge rails will be to MASH standard. Bridge Piers, Parapets, consult with District etc. Traffic Safety 2.4 Shield the Fixed Object Engineer.

If it is not practical to eliminate, relocate, or

make a fixed object breakaway, it should be consid- Signs/Lighting Consult with District ered for shielding. All traffic safety systems used to standards which cannot Traffic Safety shield fixed objects are also fixed objects. Traffic be made breakaway. Engineer. safety systems do not prevent collisions but are in-

tended to reduce the severity by shielding a fixed

object. See also Topic 3.5, Guardrail at Fixed Ob- Streams or other Typically YES, jects, for more information. permanent bodies of consult with District Longitudinal railings or barriers such as guard- water more than 2-ft. Traffic Safety rail, median barrier, and bridge railing are designed in depth. Engineer. to redirect a vehicle, and can be used to shield fixed

objects. Fixed objects within the CRZ should only be shielded when the consequences of impacting the obstacle are considered to be significantly more Typically YES, serious than striking the barrier. Drainage Features – consult with District Crash cushions can be used to shield fixed ob- ditches, headwalls, etc. Traffic Safety jects or the ends of barriers, and are designed to Engineer. safely decelerate passenger vehicles to a stop in head-on impacts. See Topic 6 for more information about crash cushions. Engineering judg- See Table 5 of commonly placed fixed objects ment based on sever- and if they are considered for shielding if within the Trees ity of obstacle and CRZ and cannot be removed/relocated or made site specific break away. circumstances.

2.5 Delineate the Fixed Object When an obstacle cannot be removed, relocated, Typically YES, made break away or shielded, the object at a mini- Controller and other consult with District mum should be delineated with an approved object Cabinets Traffic Safety marker. Engineer.

TRAFFIC SAFETY SYSTEMS GUIDANCE 14 0 3-2019 or Construction Details of Contract Plans. The lay- out of new guardrail shall be shown on the Con- Table 5 tract Plans to conform to embankment and fixed Commonly Placed Fixed Objects object criteria.

Topic – Guardrail 3.2 Guardrail Types 3.1 Introduction The approved types of guardrail are metal (W- Guardrail, installed to reduce the severity of beam), concrete and cable. run-off-road collisions, is the most common traffic safety system found on California State Highways. 1. The W-beam type Midwest Guardrail System Guardrail may redirect an errant vehicle and dissi- (MGS) is the current standard and should be pate energy from the collision in some, but not for used when W-beam is to be constructed. W- all cases depending on the sequence of events dur- beam is typical for embankment and fixed ob- ing the collision. Although guardrail is itself a fixed ject shielding. It is made up of “W” shaped object, it may reduce collision severity in situations metal beam rail elements mounted on wood or where it is determined that striking the guardrail is plastic blocks fastened to wood or galvanized less severe than striking fixed objects or slopes be- steel posts. The metal beam guardrail hind the guardrail. (MBGR) at a height of 27 ¾ or 29 inches, was the standard metal guardrail for many years. It has been replaced by the MGS, with a height of 31 inches to the top of rail, and meets cur- 1. Definition of Use: Guardrail is used as a longi- rent MASH standards. MBGR can be main- tudinal rail off of the edge of pavement to shield tained and reconstructed as referenced within areas of concern. It is typically installed to the Table 6. right of approaching traffic, but may be in- stalled to the left (e.g., one-way traffic roadbeds All wood components of MGS and MBGR are on separate alignments, ramps, or at fixed ob- pressure treated to resist decay. jects). 2. MASH Implementation: With the full imple- Line post must not be installed in structural mentation of MASH the minimum height of pavements that would restrict movement of the guardrail is 30 inches. post during impact. 3. CRZ Treatment: Consideration should first be Only one type of post, either wood or steel, given to eliminating or minimizing conditions should be used in a run of guardrail. Also, only requiring guardrail. This may be done by flat- one size of block, either 12-inch or 8-inch tening the embankment slope or by remov- should be used in a run of guardrail. ing/relocating fixed objects out of the CRZ. Vegetation control may be considered for Projects should eliminate or relocate soli- use around guardrail at the request of Mainte- tary fixed objects found in the CRZ that cannot nance and concurred by the District Traffic be made breakaway or yielding. The Length of Safety Engineer. This needs to be done at the Need (LON) for guardrail at solitary fixed ob- Project Initiation Document (PID) phase. If not ject increases the exposure to the guardrail and requested at the PID phase it will not be consid- may increase the number of collisions. ered. Details for vegetation control beneath guardrail are in the Standard Plans. Where guardrail is to be installed on an existing Typically rail elements for guardrail are highway or in conjunction with existing roadside available in two lengths: 12.5 feet and 25 feet. features, the conditions relating to the roadside fea- A 15-foot, 7½-inch rail element, or a 9-foot, ture should be verified, such as slopes, clearances, 4½-inch rail element is used for a proprietary dimensions, underground utilities, and material. terminal system connection to the MGS. The This is especially important where connections to longer rail elements may be problematic for existing structures are proposed. Details for con- maintenance to transport. structing guardrail are shown on the Standard Plans TRAFFIC SAFETY SYSTEMS GUIDANCE 15 0 3-2019 When steel posts are used, blocks cannot be At the time of publication the only bridge bar- bolted to the center of the post, as the web is in rier that is MASH complainant is concrete bar- the middle. This means the hole in the block rier 732SW which is TL2. At the time of pub- and post must be offset from center (See Fig- lication, October 31, 2019, is when all bridge ure1). When installed, the bolt should be lo- rails will be to MASH standard. For temporary cated on the traffic approach side of the post. or short-term installations, approved portable concrete barriers may be used, such as Tempo- FIGURE 1 rary Railing (Type K and Type 60K). See Block-out with Steel Post Topic 3.6 (8) for requirements on the use of Temporary Railing (Type K and Type 60K) as temporary guardrail.

Justification for use of concrete barrier as guardrail that does not meet the above criteria, or is for new construction, must be based on the recommendation from the District Traffic Safety Engineer. Documentation for this deci- sion must be placed in the project files.

Concrete guardrail shall be placed a dis- tance of 17 feet or less from the edge of trav- eled way (measured from the base of the bar- rier). Concrete guardrail must be on pavement or a well compacted base.

Concrete guardrail must be Type 60MS.

This provides a better connection to the block and minimizes the amount the block will The pavement should extend a minimum of rotate around the post in a typical collision. The 1 foot beyond the concrete guardrail (see Figure Standard Plans require the block to be attached 8). to steel posts on the traffic approach side of the Chain link may be attached on top of post yet show holes on both sides of the post so concrete barriers or guardrail if installed per the they can be placed on either side of the road- Standard Plans. Other appurtenances, such as way. steel sign posts or electroliers, but excluding structure columns or sign pedestals, may be 2. Concrete Barrier is generally damage-resistant placed on top of concrete guardrail based on the and can be used in place of W-beam guardrail following restrictions to prevent snagging: to decrease maintenance worker exposure. Cri- a. The top of the barrier is tapered up to teria for this use are when the guardrail is 48 inches, at a minimum 4:1 slope, for within 14 feet of the traveled way and it has a maximum 4 inch diameter post or, been struck three or more times in any 12 con- b. The top of the concrete barrier (up to secutive months during the most recent three- 36 inches) on the approach side shall year period that data or records are available. have a minimum 15 inch setback from The approved types of concrete barrier best the appurtenance for TL-3. suited for permanent guardrail installations on c. The top of the concrete barrier (up to the outside of the roadbed are the Type 732B, 36 inches) on the approach side shall Type 736B, Type 742B and the Type 60MS se- have a minimum 8 inch setback from ries. The approved types of concrete barrier the appurtenance for TL-2. best suited for permanent guardrail installations when integrated with the top of a structure, like See the Standard Plans for details for in- on a bridge or on top of a retaining wall, then stalling steel sign posts on top of Type 60MP, bridge barriers are used (see Standard Plans). Type 60PR, and Type 60AP concrete barrier TRAFFIC SAFETY SYSTEMS GUIDANCE 16 0 3-2019 used as guardrail, and details of structure col- 3. Operating Conditions: The location’s traffic umns and sign pedestals enclosed by Type characteristics can also affect the potential for a 60MF and Type 60MGF. With the adoption of vehicle to leave the traveled way: the MASH standards the use of Type 60S series a. Volume: The higher the volume of traffic, is no longer allowed and must not be used. the greater the potential for run-off-road See the Structures XS Sheets for additional collisions. details for structure columns and sign pedestals b. Speed of Traffic: Higher operating speed enclosed by Type 60R and Type 60SD series can increase the potential for run-off-road barriers. For more information about these de- collisions, and will affect the distance that tails go to the Structures XS Sheet site at: a vehicle will traverse before the driver can http://www.dot.ca.gov/hq/esc/tech- regain control or bring the vehicle to a stop. pubs/manual/bridgemanuals/bridge-standard- c. Merge and Weave Areas: The potential for detail-sheets/ run-off-road or lane departure collisions Note that the details on the Structures XS may increase in the vicinity of ramp merge Sheets are non-standard and require an excep- and diverge areas, especially those without tion to be used (See Appendix A). auxiliary where stopped or slowing traffic can cause abrupt lane changing and Proposed appurtenances on concrete collision avoidance maneuvers. guardrail, except Standard Plans details, must 4. Climate Conditions: Frequent dense , rain, be approved by the District Traffic Safety En- or snow and ice conditions increase the risk of gineer and documented in the project files. run-off-road collisions. 5. Roadside Recovery Area: The risk of a run-off- 3. Cable Guardrail is a high-tension three or four- road vehicle colliding with an embankment or strand flexible barrier. It may be recommended a fixed object is greater as the recovery area de- by the District Traffic Safety Systems Coordi- creases. nator for locations that can accommodate cable deflections up to 9.5 feet. See Topic 4.6(3) for The highway facility type, whether a freeway, details on cable barrier. expressway, or a conventional highway, has an im- pact on the analysis for installing guardrail due to Cable guardrail must be approved by the the differing characteristics of these facilities. For Deputy District Directors for Traffic Opera- example, the presence of driveways may prevent tions and Maintenance. Documentation of the the installation of guardrail to shield an object approval must be placed in the project files. within the CRZ. Funding limitations and differing operating conditions preclude firm rules for in-

stalling guardrail. 3.3 Guardrail Installation Criteria 3.4 Guardrail at Embankment Slopes

When considering installation of guardrail at an Installing guardrail to shield embankment embankment or a fixed object the following criteria, slopes is largely a result of analyzing the above cri- although not an all-inclusive list, may be used as a teria on a case by case basis and determining guide: whether a vehicle hitting guardrail is more severe

than going over an embankment slope. A tool de- Collision History: Based upon the run-off-road 1. veloped for evaluating this severity, the “Equal Se- collision history, statistical experience or anal- verity Curve” (see Figure 2 ), developed in the ysis can be used to evaluate if guardrail is 1960s and updated in the early 1980s, is still appli- needed. cable. 2. Roadway Alignment: Isolated curves on rela- The line in Figure 2 represents collisions at tively straight roadway alignment may increase combinations of embankment height and slope that the risk of running off road. Also, on with resulted in severities generally equal to the severity curving alignment, curves that are sharper than of an average guardrail collision. If combinations of expected may increase the probability for run- embankment height and slope plot close to the line, off-road collisions. the severity of an errant vehicle going over an em- bankment may be greater or less than the severity TRAFFIC SAFETY SYSTEMS GUIDANCE 17 0 3-2019 of striking the guardrail, so the shaded areas of the beyond the CRZ when such objects occupy an oth- line should be regarded as a band. When the site erwise clear recovery area. specific embankment height and slope conditions MGS with standard post size and spacing will plot above the equal severity band, the severity of be placed as far as possible from the edge of pave- colliding with the guardrail should be less than the ment, where the slope is 10:1 or flatter, but no severity of a run-off-road vehicle going over the closer than 36 inches from the back of the post to embankment. Therefore, guardrail can be installed the face of the fixed object. This clearance between when the embankment height and slope plot above the guardrail and the fixed object is necessary since the band, and the criteria in Topic 3.3 are consid- guardrail deflects up to 36 inches during impact. ered. Guardrail that is to be installed less than Although an embankment slope may not qual- 36 inches from back of post to the face of a fixed ify for installation of guardrail based on application object but not less than 12 inches from back of of Figure 2, the presence of fixed objects along the post to face of fixed object shall be constructed slope or bodies of water, school grounds, or other according to “Strengthened Railing Sections for fixed objects at the toe of slope or beyond the CRZ, Fixed Object” detail of the Standard Plans. See can justify guardrail at such locations. For this rea- Topic 3.6(10)(c) for discussion of this detail. son local site conditions need to be considered in conjunction with Figure 2. If guardrail is to be installed less than 12 Guardrail placed to shield an embankment inches from the back of post to face of fixed slope should shield both directions when the em- object, concrete barrier must be used. bankment is within the CRZ for each direction of travel. See Figure 3. For more information on clear See Topic 3.2 for allowable types of concrete recovery zones on conventional highways see barrier to be used as guardrail. Where there is a row Topic 2. of structure columns with less than 26 feet in-be- tween each column, the strengthened railing section The District Traffic Safety Engineer must con- detail should be continued between the columns. cur with the decision to install or not to install Where the column spacing exceeds 26 feet, a new guardrail and the type of end treatment at an em- detail may be started. bankment slope that meets the “Guardrail Less Se- Placement of guardrail, itself a fixed object, vere” conditions of Figure 2. The statement of con- may also increase the probability of a vehicle col- currence must be documented in the project files liding with the guardrail. For this reason, fixed ob- (see Topic 1.3 for guidance). jects such as individual signal poles, lighting stand- ards, utility poles, trees, or traffic control cabinets Copies of the Typical Cross Sections, Sum- are typically not shielded by guardrail. mary of Quantities and applicable Layout sheets Guardrail shall be placed at the following from the Project Plans may supplement the docu- fixed objects within the CRZ that are not mented statement of concurrence inserted in the shielded by other traffic safety systems: project files. 1. Overhead sign posts, 3.5 Guardrail at Fixed Objects 2. Structure piers, columns, and abutments, and Guardrail should be considered at all fixed ob- 3. Exposed ends of walls. jects that are accessible to traffic and within the CRZ, whether to the left or right of traffic. Guard- See Standard Plans for additional details where rail may also be considered at fixed objects located walls are above the height of guardrail.

TRAFFIC SAFETY SYSTEMS GUIDANCE 18 0 3-2019

Figure 2: Equal Severity Curve

TRAFFIC SAFETY SYSTEMS GUIDANCE 19 0 3-2019

Figure 3: Railing at Fixed Objects or Embankment Installations

EAR RECOVERY ZOH ^> CLEAR RECOVERY ZOI R THIS DIRECTION FOR THIS DIRECTION AFFIC * TRAFFIC

DIAGRAM 1 TWO-WAY HIGHWAY

(E)JXKX| P

ETW_ CLEAR RECOVERY ZONE CLEAR RECOVERY ZONE BARRIER STRIPING TO THE RIGHT SIDE OF TO THE RIGHT SIDE OF THIS DIRECTION OF THIS DIRECTION OF TRAFFIC < TRAFFIC^

DIAGRAM 1 TWO-WAY MULTTLANE HIGHWAY WTTH BARRIER STRIPING

®

— — — ~z^- TWO-WAT LEFT TURN CLEAR RECOVERY ZONE TO TH E RIGHT SI DE OF LANE STRIPIHC THIS DIRECTION OF CLEAR RECOVERY ZONE TRAFFIC < TO THE RIGHT SIDE OF THIS DIRECTION OF TRAFFIC —* ETA

DIAGRAM 3 TWO-WAY MULTTLANE HIGHWAY TWO-WAY LEFT TURN LANE STRIPING

I Ft"iFNP

© CALTRAHS APPROVED END TREATMENT, BURIED POST END-ANCHOR. OR CRASH CUSHION. IF LOCATED-OUTSIDE THE CRZ. A RAILING END ANCHOR ASSEMBLY SUCH AS A SOIL FOUNDATION TUBE (Tfpe SFTJAWCHOR OR OTHER FIXED ANCHOR HAY BE APPROPRIATE AT ENGINEER'S DISCRETION.

® HAILING END ANCHOR ASSEMBLY

[XXXl nKED 0BJECT(S)08 NON-RECOVERABLE EH BAHKHENT SLOPE TRAFFIC SAFETY SYSTEMS GUIDANCE 20 0 3-2019 nal needed to shield an area of concern by con- When evaluating placement of guardrail to taining or redirecting an errant vehicle. The shield rows of trees within the CRZ that have trunks LON is defined as that point on the terminal or 4 inches or greater in diameter, consult with the longitudinal barrier downstream from which it District Traffic Safety Engineer. More emphasis will contain and redirect an impacting vehicle should be given to those trees spaced 100 feet apart along the face of the terminal or barrier, shield- or less. ing it from impact with a fixed object (See In medians or roadway separations that are less Roadside Design Guide for Length of Need cal- than 100 feet wide and traversable by vehicles, culations). structure piers or columns should be shielded with The LON generally includes some portion guardrail with appropriate end terminals and/or of the end treatment: for gating end treatments, crash cushions if not otherwise shielded. all except the last 12 ½ feet of the end treat - Guardrail placed to shield a fixed object on a ment is effective barrier (contributing to the two-way highway should shield both directions LON requirement). Non-gating end treatments when the object is within the CRZ for each direc- are capable of redirecting a vehicle impacting tion of travel. See Figure 4: Railing at Structures, the nose or the side of the system along the sys- Diagram 6, for illustration of CRZ on multilane tems entire length. highway structure with asymmetrical roadway lay- Gating end treatments allow a vehicle im- out. For more information on clear zones on con- pacting the nose or the side of the system near ventional highways see Topic 2. the nose to pass through the device. For gating Guardrail placed to shield a fixed object on a end treatments, the LON will usually start 12 two-way multilane highway with a two-way, left feet-6 inches from the impact head or at post 3. turn lane, should protect adjacent traffic if the fixed Because gating terminals will allow a vehicle to object is within the CRZ. pass through the system on a side angle impact within the first 12 feet-6 inches, additional The District Traffic Safety Engineer must con- length of rail should be considered to account cur with the decision to install or not to install for the run out distance of the vehicle. guardrail and the type of end treatment at a fixed The majority of run-off-road collisions oc- object. The statement of concurrence must be doc- cur at departure angles between 10 and 15 de - umented in the project files (see Topic 1.3 for guid- grees, with 12.5 degrees typically used to deter- ance). mine if guardrail shields an object. The minimum LON should be 150 feet for Copies of the Summary of Quantities and ap- all guardrail installations. Additional length plicable Layout Sheets from the Project Plans may may be required depending on the location of supplement the documented statement of concur- other fixed objects or features being protected rence inserted in the project files. that may exist behind a guardrail run. This length is inclusive of the WB-31 transition, 3.6 Guardrail standard MGS line rail and any approved end terminal up to its LON point, which is typically

starting at post 3 of the terminal system. Design Considerations The LON will vary depending upon site conditions and the guardrail layout. As the set- This topic addresses site-specific considera- back to a fixed object increases, so will the tions involved in designing a guardrail layout. It LON required to shield that object. Likewise, discusses the length of guardrail needed to shield an for locations with multiple objects within the area of concern, as well as the lateral placement rel- CRZ, such as a bridge approach rail on an em- ative to the area of concern. It also covers uses of bankment with trees, the LON to be considered guardrail at structures and drainage features, and should be sufficient to shield the approach rail, addresses appropriate cross slopes. It discusses end embankment, and the other fixed objects. treatments and transitions to structures, gaps in Figure 5a, Position of Guardrail at Fixed guardrail installations, and concludes with various Objects, illustrates how additional guardrail is other design details. needed to shield an area extending back from 1. Guardrail Length of Need: LON is the total the edge of the roadbed on a one-way road. Fig- length of guardrail and portion of the end termi- ure 5b also illustrates how the length of a TRAFFIC SAFETY SYSTEMS GUIDANCE 21 0 3-2019 guardrail installation may be reduced where and the nature of the adjacent terrain. See there is a wider clear recovery area between the Figure 3. edge of the and the fixed object. b. Multi-Lane Highways with Separate Where fixed objects are added behind ex- Structures: Guardrail should be placed to isting guardrail, care should be taken that all the right and left of approaching traffic. fixed objects are within the area shielded by the Railings, guardrail, and bridge railing guardrail. Fixed objects shall not be allowed should not be placed transversely across behind, or in front of, breakaway anchors, the median or separation openings be- end treatments, or where posts are removed tween adjacent or parallel structures. Pro- in a run of guardrail tection should be provided by bridge ap- The District Traffic Safety Engineer or their proach guardrail with adequate length and designee must concur with the LON for em- an appropriate typical layout. Details re- bankment and fixed object guardrail for all in- garding guardrail typical layouts are con- stallations. The statement of concurrence must tained in the Standard Plans. be documented in the project files. c. Multi-Lane Freeways or Expressways with Copies of the Typical Cross Sections, Sum- Decked Medians: Guardrail should be mary of Quantities and applicable Layout placed if the bridge rail is within the CRZ. Sheets from the Project Plans may supplement The CRZ should be considered in both di- the documented statement of concurrence in- rections of travel. If the distance from the serted in the project files. lane line to the bridge rail is more than 30 feet, guardrail is not required, but may be 2. Guardrail Placement and Position: For illus- considered based on site specific condi- trations of guardrail at structure approaches in tions. See Figure 4. When the bridge the following applications, see Figure 4. Struc- clear width is 60 feet or more, guardrail ture approaches apply to the ends of bridge rail- should be placed only to the right of ap- ings, parapets exposed to approaching traffic, proaching traffic. curb, and dike. Where guardrail is 3. Curb and Dike: Placement of dike near W- needed at structure approaches or concrete bar- beam guardrail requires special consideration rier, transition railing of the Standard Plans to prevent vehicles from vaulting over the rail. should be used unless site conditions support Vaulting may occur when W-beam guardrail use of a crash cushion system. Refer to Topic 6 deflects enough for the wheels to mount the for more information on crash cushions. If curb dike, lowering the effective height of the w- or bridge barrier without a vertical face is pre- beam and allowing the vehicle to vault over it. sent, refer to Structures XS Sheets (Barriers and Mountable dike shall not be placed un- Railings) for non-standard connection details. der W-beam guardrail. The increased height The use of these non-standard details will re- of MGS compared with MBGR allows for the quire that the Exception to Traffic Safety Sys- placement of up to a 6 inch height curb or tem Standards be filled out. Where a curb or (TYPE A) dike under the rail if 12” blockouts sidewalk is present, traffic is one-way and ap- are used. 6 inch curb or (Type A) dike must proach speeds are 45 mph or less, the connec- not be used with 8” blockouts. Dike should tion details in Figures 6a and 6b may be used. typically be constructed with the base of dike See Note 1 of Figure 8 for design requirement being flush with the face of rail (A Construc- from Headquarters Geotechnical Services. tion Detail may be required). Dike up to 6 a. Two-Way Conventional Highway: Guard- inches may be placed with MGS if 12-inch rail should be placed at bridge approaches blockouts are used, so that the base of the dike if the bridge rail is within the CRZ. The extends up to 7 inches from the face of rail. CRZ should be considered in both direc- Dike placed more than 7 inches in front of the tions of travel. Guardrail should be placed face of rail with MGS shall be 2 inch (TYPE on both sides of the roadway if the dis- C) dike as shown in the Standard Plans. tance from the centerline to the bridge rail When installing MGS with dike in snow is 20 feet or less. If more than 20 feet, areas, it may not be desirable to place dike guardrail may be placed only to the right protruding from the face of rail, as it may in- of approaching traffic, however it may be terfere with snow removal and other opera- considered based on site specific geometry tions. In these cases a construction detail may TRAFFIC SAFETY SYSTEMS GUIDANCE 22 0 3-2019 be needed to construct dike so that the base of to the cross slope of the roadway. When w- dike is placed flush with the face of rail. beam guardrail is considered for installation To prevent a vehicle from vaulting over where the cross slope is not on the same plane MGS with 8-inch blockouts, or MBGR, when as the adjacent pavement slope, but not greater they are used in conjunction with a 4-inch than 6:1, it is necessary to determine whether high curb or dike (Type F), the guardrail face the trajectory of the impacting vehicle has sta- will be on a vertical line with the curb face or bilized back to the ground prior to impact. A on a line no more 2 inches behind the flow discussion of calculating vehicle trajectory is line of the dike. A curb or dike greater outlined in Traffic Bulletin No 15, “Method than 2 inches in height, ditches or drainage for Checking the Integrity of Cable and Beam structures shall not be placed in front of Barriers” and in the Roadside Design Guide MGS with 8-inch or 12-inch blockouts or Section 5.6.6.2. where MBGR is used. Where placement of Possible vehicle trajectory must be dike is required in front of MGS with 8-inch checked, and documented in the project or 12-inch blockouts or MBGR, Type C dike files, when guardrail placement is pro- may be used. posed behind a slope steeper than 10:1.

It can be difficult to construct dike com- pletely under MBGR rail, due to space con- The trajectory of a vehicle should also be straints. In snow areas, 12 inch blockouts may evaluated on the high side of a superelevation be considered so that the base of the dike may even if the shoulder slope is 10:1 or flatter be- be placed flush with the face of rail. Dike cause of the grade break between the two placement for MBGR is no longer shown in slopes. The height of the rail may need to be the Standard Plans, therefore a construction raised above the standard height to minimize detail is needed when dike is used in combina- the chance of a vehicle vaulting over the rail. tion with MBGR. As the rail height is increased, longer posts Only 2 inch (Type C) dike is allowed in may be needed to maintain post embedment front of end terminal systems and within 25 and rub rail may be needed to keep vehicles feet in advance of the end terminal system as from going under the rail. shown in the Standard Plans. 5. W-Beam Installed in Paved Areas: Line posts 4. Cross Slopes: The cross slope from the edge must not be installed in structural pavements of shoulder to the w-beam guardrail shall as it restricts the movement of the posts during be 10:1 or flatter, except when conforming impact. TRAFFIC SAFETY SYSTEMS GUIDANCE 23 0 3-2019

Figure 4: Railing at Structures

1 1 1 —-^-^ q • • J • ©I ffi ••J-** | ® 1 • ^TP~ 1 —c 1 1 VEDGEJOF TRAVEL WAYS VE&GEJ OF TRAVEL WAY-y _

DIAGRAM 4 DIAGRAM 5 UNDIVIDED ROADWAY UNDIVIDED ROADWAY TWO WAY HIGHWAY STRUCTURE TWO WAY HIGHWAY STRUCTURE ROADBED LESS THAN40 FEET ROADBED EQUAL.TO OR GREATER THAN 40 FEET

[ I •

EDGjE OF TRAVEL |WAY% i ! \ immjimm rz> FDRTHSHBECnCWOFTRWa "

DIAGRAM 6 MULTILANE HIGHWAY WITH ASYMMETRICAL ROADWAY LAYOUT

^>-EDGE OF 1 RAVEL WAY

® W" ^EDGE OF TRAVEL WAY <=, hlF.rn.t'. h..kh:lb Ft |

~ - r=7 EDGE OF TF1AVEL WAY*£

DIAGRAM 8 DIAGRAM 7 MULTILANE HIGHWAY WITH MULTILANE HIGHWAY WITH SEPARATE DECKED MEDIAN STRUCTURE STRUCTURE FOR EACH DIRECTION OF TRAVEL

LEG EN D © Catiransappro^erdbeai^ (D TrarmMi Railing wthandwag^ostruajre. © Railin gend anchor assembly. © Po#^archcf3getosiu±rie • Stncure TRAFFIC SAFETY SYSTEMS GUIDANCE 24 0 3-2019

Figure 5a: Position of Guardrail at Fixed Objects

TRAFFIC SAFETY SYSTEMS GUIDANCE 25 0 3-2019

Figure 5b: Length of Need Determination

• UJO ^

z< y v ,R|„ EN VD TREATMENT BEGINNING LENGTH OF NEED 'OR M ft * „.* _ \ ' R (FO APPROACH END ANCHORAGE ASSEl

CELIMIT^ f Ji f ^ X'IL±^—^ L X I yj^T^r^ D FREE HAZAR, TRAVERSABLE SLOPES

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(LEFT SIDE OPPOSITE HAND) ONE-WAY TRAFFIC NOTNOT TOTO SCALESCALE

BEGINNING LENGTH OF FEED £A) « | BEGINNING LENGTH OF NEED (RA} , Jii , BACK OF FDED OBJECT) U / I X (LENGTH QF NEEP) FT. _ 1 ' X(LENOTHOFNEED)FT.

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END TREATMENT WBFHM^Sim-C^lJJ 1 J _ ^-v. (APPROACH END ANCHORAGE ASSEMBLY • OPP05INO DIRECTION , «•««•« £f f j EhlOTREATMENT tFfPEWIES1 * . OPPOSING DIRECTION

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TWOLANE TWO-WAY TRAFFIC NOT TO SCALE TRAFFIC SAFETY SYSTEMS GUIDANCE 26

0 3-2019

Figure 6a: Connection to Bridge Curbs

Note: Only use where traffic is one-way and approach Speeds are 45 mph or less

I rtsfws ~ — 1 inchor bolts f ^ IfV x ID/1 x fl'-a" - lW" \ -oda wrTh Vj— ,

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SECTIOH B-B SECTION C-C ANCHOR POST ASSEMBLY ANCHOR POST DETAILS To be galvanized after fabrication

r—rz —i— i f 11 ^ 0UD1" rwmlnal 1*^4*^* ttilchnesa. | 5ar* shape ^ ij L' Weld T" as roll element " Y " Witlort——^"^—f-—rpf^— *fjS" Holes r* ^ 1 METAL BOX SPACER PETAL A BACK-UP PLATE Place I" baits throuari Far use between I'.'J" f x '.•'••<" riK spacers --I--In--I--t- (1:1 In: t II MM 1- =-:r - pdsslr^ -ttii-Gugh ban Intoi-lai-. TRAFFIC SAFETY SYSTEMS GUIDANCE 27 0 3-2019

Figure 6b: Guardrail Connections to Anchor Posts

Note; Only us e wher e traffic is one way an approaca h speeos are 45 mph o lesr s

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E3 NOTES

1, Use this detail when posts cannot be embedded @ © to the minimum depth shown on Standard Plan I—IF—I A77LLAND A77L2 i ^—i 2, Unless otherwise specified use either the circular saw re* IVooWoodd PosPostt Wood Post or the oblong bole configuration for case 1 conditions, 3, Crushed course aggregate backfill conforms to "course aggregate for concrete. 4, Place crushed course aggregate according to the post requirements. Q 5, This width may be Increased to 15". to accomodate StUl POS

construction tolerances. 1 6, 2' diameter hole may be used. I—F— PUN HEW 7, Standard post embedment is; Steel ft»t 42" for MBGR at 29" 43" for MBGR at 27-2/4" PUN VIEW o 40" forMGS to o

VO 00 I Wl»

I. TO R CONCRET HHIE U LENGTHS LES THAS lSO'lVON R HIKE BIDTH <•S r BEHIN TID C CONCRET BARRIERE CONTAC. GEOIECHNICAT VOUCHL FOR DESIGN CRITERI ISOIAL CONDITIONS!

iw sen CONCUHSHO ii E TRAFFI C OPERATION S BRANCH 1, 10'B1 IS FOOTIN" 5HU.G L BE UOO.IIBI C tllH IH[ CONCRET BARRIEE OB RTH FOOTIhE C rWWKgWga SHOAPCB STRUCTURAL SECTrO W HAllltHO CII-IL •«•][• ttlt/^^ SHAL L BE CONITFUTC WNOLITHID tITBC TIC ir EROSIO N TCHCU ANE D TIC CONCRETE BARRIE SER T ATO P TIC FOOTING AN CONNECTED RITD H 1 REINFORCIN STIRRUPG .

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4. CONSTRUCT FOOTIN ENTIRG E LENGT OH F CONCRETE BARRIER iW trmiM-f tx eanrfftrsf sown or TRZ ™ * L I

5. HIST DORE NXL * CONCRET GUARDRAIE BARRIEL R INT O EIISIIHG CONCRET BRIOCE E RAI L AND/OR "•" ^ —^ BRIDG E RIN BALG L TO NINIUII E ROTATIO O FN CUARORAlL *

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Ml SCALE re S» For QtWl+lcjngl Qtjfolh of foplcol oonnirc + i onj +0 OritJtW roll, Ul Connection LlBtall nn itannard Plana AJTU1 ana 3 Ally.? dna CcwnirttliVi DftTdil FF on Stanadrd Pinrii BP ITTOi LUTED J»MM*T M Mi T AL>CAtCKt tritfAJ* PL*H »M)i LrlHD OCTOBC HX, Zfll* - P*tJ H tf THE STlHB-m PL-H B5W n,T|n joijj. •j .Fry aaa'tianal uata'li of d typical cdrinvctiai to id II. o' doutiritnta, w •It StfjrKJorrJ Plan ilTul. Ho TRAFFIC SAFETY SYSTEMS GUIDANCE 31 0 3-2019 6. W-Beam Installed in Rock: If posts need be in- a tension member, much like a bowstring, redi- stalled in rock then the following procedures recting the errant vehicle away from the obsta- should be used. When installing posts in rock cle. Thus it is necessary that both ends of all the hole size required will depend on the guardrail installations be anchored. Concrete amount of soil over the rock (See Figure 7). guardrail shall be anchored to prevent When there are 18 inches or less of soil above movement. Type 732B, 736B and 742B are the rock, 15 inches of clearance behind the post anchored by continuous footings; Type 60MS will be provided for the entire embedment series requires a 10-foot long footing at each depth. If there is more than 18 inches of soil end. On runs of Type 60MS barrier that are above the rock, a 12 - inch diameter hole will used as guardrail and are 150 feet or less, the be drilled into the rock far enough to allow full footing is added over the entire length. For runs post embedment. Backfill in the same manner of Type 60MS barrier that are used as guardrail as a post installed in a paved area (See Figure and are 500 feet in length or less, a footing is 7). Further guidance may be found in the Road- added at each end. For runs greater than 1000 side Design Guide, Sec.5.6.7. feet in length, a footing is added every 250 feet. 7. Cut and Fill Slopes: When guardrail is placed Footings added on runs of concrete guardrail in a cut slope, there shall be a minimum are to minimize movement of the barrier upon clearance of 15-inches from the back of post, impact. Concrete guardrail footings must be in at the base, to the toe of slope. There shall pavement or a well compacted base. The pave- also be a minimum clearance of 3 feet from ment must extend a minimum of 1 foot beyond the back of post, at the top, to the face of the concrete guardrail footing or if placed on a slope. This is to allow the guardrail to deflect well compacted base must have a monolithic as it would on a fill or level plane, See Figure tongue constructed with the concrete guardrail 9b. The 15-inches from back of post to toe of that extends 1 foot beyond the backside of bar- slope does not apply to the buried end anchor rier. (see Figure 8). Temporary Railing (Type from the beginning of parabola point to the bur- K) is anchored by 1-inch diameter dowels for ied anchor. A 3- foot minimum clearance from temporary and long-term use while Portable back of post to fixed objects should be main- Concrete Barrier (Type 60 K) is not staked. See tained with guardrail. End treatments, except the Standard Plans for staking details for Tem- for buried ends, shall laid out as shown in Fig- porary Railing (Type K). ure 9a and the Standard Plans for placement on (repeat of what is stated above) Type fill. Additional area will be required for both 60MS series and Temporary Railing (Type K the in-line and flared end treatments when and Type 60 K) should be supported by a 4-inch placed near cut slopes for these systems to per- thick asphalt or concrete pad that begins from form as they were designed. the edge of the pavement and extends 12 inches beyond the back edge of the concrete guardrail. FIGURE 9b If the pad cannot be extended 12 inches beyond W-Beam near Cut Slopes the back edge of concrete guardrail, other measures should be used to prevent soil ero- sion. Pavement should extend to the footing of the Type 732B, 736B and 742B barriers. Type CA Cable Anchor Assembly (non- breakaway) shown in the Standard Plans can be used only where the end of a guardrail installa- tion cannot be impacted by an approaching ve- hicle. A non-breakaway anchor should be used to add intermediate anchorage where there is an abrupt change in the alignment of the guardrail, such as when the guardrail is continued down an intersecting road or if there is an area of con- cern on the side slope that would cause a more severe collision than impacting the guardrail.

8. Guardrail Anchorage, Transitions and Ap- Standard Plan A77T1 shall be used for a proach End Treatment: Guardrail functions as non-breakaway anchor. If there is no area of TRAFFIC SAFETY SYSTEMS GUIDANCE 32 0 3-2019 concern on the side slope, then a breakaway an- such as bridge railings, retaining walls, chor with drilled posts set in a foundation abutment walls, sound walls or other struc- should be used for intermediate anchorage. ture supports. Stiffening smoothly redi- Guardrail approaching structures is an- rects an impacting vehicle away from the chored to, or near the structure. In general, rigid object and shall be accomplished guardrail may be anchored to structure railings by using the Transition Railing and Con- that are designated barrier railings. nection Details of the Standard Plans. Guardrail shall not be anchored to struc- 9. Gaps Between Guardrail Installations: Gaps of ture columns or abutments unless detailed in less than 200 feet between guardrail installa- the Standard Plans, as holes drilled for an- tions, or between the end of cut slopes and the chor bolts can compromise the integrity of beginning of guardrail, should be avoided. earthquake reinforcement. Where existing Where such a gap is essential for maintenance masonry and lightly purposes, removable rail elements can be in- walls are involved, an independent anchor stalled. For additional information on rail pan- shall be used. Connections may be made to els, consult the District Safety Systems Coordi- new installations of concrete barrier. nator. a. Approach End Treatments: The order of A gap for maintenance use may be left at preference for approach end treatments is the departing end of embankment guardrail on as follows: one way roadbeds, or two-way roadbeds where i. Bury the end of the guardrail in a non- the departure end is outside of the CRZ. Where traversable slope. It may be necessary there is recovery area between the edge of the to extend a guardrail installation a rea- traveled way and the edge of an embankment, sonable distance to reach a cut section the guardrail should be installed near the edge where a buried end anchor can be used. of the embankment, preserving the recovery A minimum height of 30 inches to the opportunity. top of guardrail is to be maintained to 10. Design Details: There are a number of factors minimize vaulting. that must be taken into consideration when in- ii. Extend the end of the guardrail at a stalling guardrail. 20:1 or flatter flare for concrete, or a a. Restricted Horizontal Clearance to Hinge 15:1 or flatter flare for W-Beam, to a Point: Where embankment width between point outside the CRZ. the edge of shoulder and hinge point is less iii. Install an approved end treatment at the than 4 feet, there is not sufficient soil to approach end of the guardrail. support a standard length W-beam guard- For more information on which end treat- rail post. If there is at least 2½ feet of this ments are approved for use on California embankment width but less than 4 feet, and State highways and for assistance in choos- standard MGS is to be installed, a 7-foot ing an appropriate system, contact your long, 8-inch x 8-inch wood post or an District Traffic Safety Systems Coordina- 8-foot long steel post should be used. See tor. Figure 10, Midwest Guardrail System on All in-line end treatments are to meet Standard and Narrow Embankments. This MASH standards and be Caltrans ap- design may also be used where embank- proved. As of April 30, 2018, all flared end ment material is non-cohesive. If there is treatments will have to meet MASH stand- less than 2½ feet between the hinge point ards, and be Caltrans approved. and the edge of shoulder, the concrete beam b. Trailing End Anchorage: The End Anchor detail in Figure 11 may be used. Another Assembly (Type SFT-31) is intended for potential option where there is less than 1⅔ use on the trailing end of guardrail installa- feet between the hinge point and the edge tions that are outside the CRZ of opposing of shoulder is use of a 2-foot diameter cast- traffic. See Figure 3. in-drilled-hole pile (CIDH) to support a c. Transitions to Structures: Transitions are W6x8.5 or 9 steel post for MBGR. Under required for guardrail approaching connec- the same conditions CIDH piles cannot be tions to structures. MGS is a semi-rigid bar- used for MGS. Instead either wood post of rier and must be gradually stiffened as it ap- 8-feet in length or steel post of 9-feet in proaches connections to, or at rigid objects length will need to be used. For MBGR use TRAFFIC SAFETY SYSTEMS GUIDANCE 33 0 3-2019 fixed object. This detail uses reduced post spacing of 37½ inches and larger posts and of the CIDH detail should be limited to no blocks to transition from the standard post more than six consecutive posts for spacing and size. The wood posts are 10- MBGR. Details for these alternate designs inches x 10-inches x 8 feet long with 8-inch are shown in Figure 10. x 12-inch blocks. The alternate steel posts Use of CIDH piles for MBGR and the are a W6x15 section and the blockouts are use of 8-foot wood or 9-foot steel post for 8-inch x 12-inch wood or plastic blocks. MGS, on very narrow embankments, must All steel parts are to be galvanized. Details be approved by the Headquarters Traffic of the “Strengthened Railing Section for Safety Systems Branch. Fixed Objects” are shown in the Standard b. Restricted W-beam Post Embedment Depth Plans. or Placement: When it is necessary to con- d. Adjusting Rail Height: All W-beam guard- tinue a roadside guardrail across an, under- rail posts have holes for adjusting the rail- ground obstruction full embedment of the height for an overlay to be placed on the guardrail post(s) may not be possible due to shoulder. The adjustable post had three the shallow soil cover. Posts located in an predrilled holes per the 1995, 1997 and overside drain are undesirable and are 1999 Standard Plans and has two holes per therefore often set back behind the drain the 2004, 2006, 2010 and the 2015 Stand- with multiple blocks. The use of more than ard Plans, which allow the rail element and two blocks can cause guardrail rotational block to be raised when an overlay is problems and should be avoided. placed on the shoulder. Details of the com- One, two or three posts located directly ponents are shown in the Standard Plans. over the culvert or drain may be eliminated. See Figures 14a and 14b for installation de- The three consecutive posts adjacent to tails. Pavement overlays that impact the both ends of the gap shall be controlled re- effective height of rail elements shall in- leasing terminal posts. Design details are clude the required action from Table 6 shown in Figure 12a, Long Span MGS. for MBGR and MGS. Concrete guard- Long Span MGS should not be used in tran- rail cannot be capped to increase its sition areas, or where a fixed object is height. Instead it must be removed and closer than 12-feet due to increased rail de- replaced with new barrier as outlined in flection. Table 6. An alternative design to Figure 12b is e. W-beam Rail Curvature: W-Beam Guard- the special post footing shown in rail can be installed on curving alignment Figure 13. Figure 12a and Figure 12b are without special fabrication where the ra- for MGS and MBGR. Show details for re- dius of curvature is more than 150 feet. moving up to 3 posts with MGS and up to Where the radius of curvature is 150 feet or 2 posts with MBGR. This detail may be less, down to a minimum radius of 5 feet, used only where standard embedment of the rail elements require shop rolling to the railing post is restricted by underground fa- required radius. Installations of guardrail cilities, such as drainage structures, utili- with specially fabricated components ties, footing of walls, columns, etc., No should be held to a minimum to reduce the more than three consecutive posts with need to stockpile special components for this design shall be used for MGS and maintenance. Also, where special compo- 100 feet of unaltered rail shall be placed nents are not stockpiled, the delay in order- between any skip post detail. ing and receiving replacements unneces- sarily extends the exposure for traffic. Use of Figure 13 must be approved by f. W-Beam Guardrail Delineation: Galva- the Headquarters Traffic Safety Systems nized steel guardrail provides some supple- Branch. mental value as a delineation device. c. Strengthened MGS Rail Sections: Topic 3.5 Where necessary, this delineation ability discusses application of the strengthened can be enhanced with reflective delineation railing sections detail where W-beam devices as described in the California guardrail is installed less than 4 feet from a MUTCD. Reflective delineation devices TRAFFIC SAFETY SYSTEMS GUIDANCE 34 0 3-2019 used on guardrail installations should pro- the District Maintenance Engineer or re- vide optimum visibility. Guardrail located view the State of California FIRE HAZ- more than 12 feet from the roadbed should ARD SEVERITY MAP published by CAL not have reflective delineation devices in- FIRE at http://www.fire.ca.gov/fire_pre- stalled. Guardrail intruding on the roadbed, vention/fire prevention wildland statewide such as at approaches to narrow , to determine if a project site is in an area warrants additional delineation treatment containing flammable vegetation that re- as described in the California MUTCD. quires use of steel posts for guardrail. g. Aesthetic W-beam Guardrail Treatment: i. The use of Steel Post in Environmentally Weathered steel or ungalvanized steel is Sensitive Areas: Steel post may be pre- allowed only where rainfall is less than ferred as they are driven and not augured 8 inches per year and there is no salt in thereby minimizing soil disturbance. the area. Additionally, all new and exist- j. Thrie Beam Barrier Used as Guardrail: ing installations of weathering steel or Thrie Beam Barrier may be used as guard- ungalvanized steel guardrail or median rail only in special situations where addi- barrier shall be examined annually to tional height of rail is needed. Refer to determine their conditions. Those instal- Topic 4.6(2) for more information about lations showing signs of advanced deteri- the design of thrie beam barrier. oration shall be replaced as soon as pos- k. Curb and Dike in front of Guardrail: The sible. Advanced deterioration is defined following are restrictions exist on the as visible tubercular rust signs. Replace- placement of curb or dike in front of ment parts shall be galvanized. For more guardrail. on Aesthetic Metal Guardrail Treatments, • Midwest Guardrail System: Refer and the options, refer to Landscape Archi- to Topic 3.6(3). tecture, Highway Metal Guardrail Aesthet- • Concrete Guardrail: Curb or dike ics, see Landscape or at: shall not be placed in front of http://www.dot.ca.gov/hq/Land- concrete guardrail. Arch/16_la_design/research/aesthet- • Cable Guardrail: Cable Guard- ics.htm rails are proprietary systems. If h. Use of Steel Posts in Fire Prone Areas: All curb or dike are needed then new and replacement W-beam guardrail curb or dike shall be installed should be specified with steel posts if the per manufactures recommenda- surrounding environment contains poten- tions tial fuel for wildfires. This restriction does l. Pullouts: At pullouts, guardrail may be not apply to transitions to bridge rails or routed around the perimeter of the pullout concrete barriers. Guardrail in roadside ar- but should maintain the 15:1 for W-Beam eas with no proximate fuel sources may use and 20:1 for Concrete, or flatter, flare in wood or steel posts. However, guardrail the departing end from the back of the post and block type should be consistent in pullout. a single installation or run. Consult with .

TRAFFIC SAFETY SYSTEMS GUIDANCE 35 0 3-2019

Table 6: Railing and Barrier Restoration Practice*

Existing Railing or Overlay Height (in) Required Action Barrier Tolerance (in) - Replace with MGS if top of rail is below 29” or Metal Beam +1 29 above 30” Guardrail (MBGR) - 8 inch blockouts must be used. Raise block and rail using additional hole(s) in post. Midwest Guardrail +1 If out of tolerance: 31 System (MGS) -2 - Add rub rail if top of rail is above 32” - Reconstruct if top of rail is below 29” Should be upgraded per policy to current standards. Metal Beam Bar- 30 N/A If not, contact the Headquarters Traffic Safety Sys- rier tems Branch Thrie Beam 32 0 Reconstruct if top rail is below 32” Remove and install Type 60M Barrier even if height Type 50 32 0 is not reduced and shoulder cross slope is not greater than 10:1. Remove and install new Type 60M or Type 60MG Type 60MS 36 0 Barrier. Remove and install new Type 60M or Type 60MG Type 60M 42 -6 Barrier.

Consult The District Traffic Safety Engineer and the All Other Barriers N/A N/A Bridge Barrier & Railing Specialist – Division of Engineering Services. Remove, raise pad to grade and replace cushion all Crash Cushions N/A N/A per manufacturer. *Check with the District Traffic Safety Engineer and the District Safety Systems Coordinator be- fore proceeding with these practices.

TRAFFIC SAFETY SYSTEMS GUIDANCE 36 0 3-2019 11. Offsetting and Overlapping Guardrail: treatments used at the approach and - Guardrail is meant to prevent collisions with ing ends of guardrail to shield embank- fixed objects or non-traversable/non-recover- ment slopes. able slopes when these events are more se- b. Structure Approach and Departure Lay- vere than impacting the guardrail itself. As outs: such, guardrail is limited to when it is actu- The Type 12 Layout series are used ally needed. Overlapping one guardrail sys- to shield the approach or departure ends tem in front of another defeats this. If an issue of structures with an allowable end treat- exist with an existing system it should be re- ment. moved and replaced with a current system. Layout Types 12A, 12B and 12C il- The only time offsetting and overlapping is lustrate allowable end treatments used at advisable is when a gap is needed like at a structure approaches, to the right or left MVP. Therefore, except at the end of of traffic. guardrail system where overlapping will Layout Type 12D is used where con- eliminate the need for an end treatment, or tinuous guardrail is installed between is for Maintenance openings, guardrail structures. Layout Type 12E is used to systems shall not overlap. the left of approaching traffic at the end 12. Typical Layouts: W-beam guardrail typical of each structure on multilane freeways layouts are designed to place the ends of or expressways. guardrail installations away from approach- Layout Type 12E is used where ing traffic and provide a smooth transition. guardrail is installed in the median to Placement is controlled by such factors as shield both the approach structure and the embankment width, distance between road- structure on the opposite side of the me- beds, clear roadside width, and the design of dian if it is less than 50 feet from the edge the guardrail itself. The layouts shown in the of traveled way. Standard Plans are both general and typical. Layout Types 12AA, 12BB and They are most applicable to new construc- 12CC illustrate allowable end treatments tion; however, any installation may require used at structure departures. some modification to fit special circum- Layout Type 12DD is used where stances. guardrail is recommended to shield em- Deviations from guardrail typical layouts bankment slopes only for adjacent traffic. must be approved by the District Traffic c. Fixed Object Layouts: Safety Engineer and documented in the pro- The Type 14, 15 and 16 Layout series ject files. are used to shield fixed objects. a. Embankment Layouts: Layout Type 14A is used to shield The Type 11 Layout series are used fixed objects between separated roadbeds to shield embankment slopes where in two-way traffic and Layout Type 15A guardrail is recommended. is used to shield objects between sepa- Layout Types 11A, 11B and 11C are rated roadbeds in one-way traffic, using used where guardrail is recommended to allowable end treatments. shield embankment slopes only for adja- Layout Types 16A, 16B and 16C are cent traffic, using an allowable end treat- used to shield fixed objects only for adja- ment. See Topic 3.6(8) for information cent traffic, using allowable end treat- about allowable guardrail end treatments. ments. Layout Types 11D through 11L illus- Layout Types 16D through 16L illus- trate combinations of allowable end trate combinations of allowable end treatments used at the approach and trail- ing ends of guardrail to shield fixed ob- jects. TRAFFIC SAFETY SYSTEMS GUIDANCE 37 0 3-2019

Figure 10: Guardrail on Standard and Narrow Embankments

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CASE 11 [ONE POST CONFLICT, MOvE THE POST cod ADD ONE POST) (NO NESTED PAIL REQUIRED} -*f^\ i—RAIL 5PL.ICE.

| | IH | | J/V 1 n fi iin. i i - fa f f m ! F h .. I TV I i il i j i \ ? H I j 1 1 ^ EXISTING GUARDRAIL r VI 1 1/ \S'-t" ^ I— ADD]T1C*14L GUARD P1AIL1HG LZ \ CASE lb I i / • '•• LAP UNDER 2 a) \ / fu-.i" Y PRECEDING RAIL rq ^ (ONE POST QUIT TED AT CENTER OF OF ELEMENT) [NEST THREE LENGTHS OF RAIL REOUIRED] CASE 2 (ONE POST OMITTED AT JUNCTION OF 1KB ELEMENTS] « H (NEST THO LENGTHS OF RAIL REQUIRED)

NESTED GUARD RAII itl itl U XT 111 m r SPLICE "4 RAI RAI L ELEMENT ELEMENTSS S SPP L I 5^ I i / 4NSND BOLTE BOLTEDD TGHROL TGHROUGK H |\ /\ / (ONE SET INSIDEO 'I' I'I'I N r'i 'I' 4 y ^ Ml *JJ ! > i' rv g w pJOOrj OR STEEL POST —L SECTION B-B RAILING SPLICE

SECTION A-A ^0 CASE 3 lT#0 POSTS QUITTED] TYPICA L RAILIN G OVERLAP [NEST THREE LENCTHSee Noti OFe J RAIL REQUIRED! INSTALLATIO N AT POST See NOK J « > NOTES. LONG SPAN NESTED GUARD RAILING 1. NEST ALL RAILS IT EXISTING RAIL LAPS 1. nHEI. A POST 15 REMOVED J'lC THE RAIL ELEMENTS ARE NESTED. THE NESTED ELEMENTS MUST BE SUPPORTED BY * U]N OF z POST CONSTRUCTIO N DETAILS EACH SIDE DF THE MISSING PD5T DR ADD ADDITIONAL LENGTH OF NESTED ELEMENTS. MBGR J. MAXIMUM OF TWO POSTS MAT EE OMITTED AND THE NESTED RAIL ELEMENTS ARE SUPPORTED Br A MIN OF REMOVE POST OPTIONS POSTS EACH SIDE OF THE MISSING POSTS. t. EXISTING, UTILITY FACILITIES ARE NOT SHOP ON THESE PLANS. NO SCALE C-! TRAFFIC SAFETY SYSTEMS GUIDANCE 41 0 3-2019 Figure 13: Special Post Footing Detail

- SEE NOTE 1 t 6'*12'fwMGSand6 x3'forMI

Top at rait ^

1| N « K 6* x 8" Wood Post F \

1/2" Polystyrene -._ —,—\ \—r Ground line — — ——T —pfe fiJ ; U it"8 ~ ^e w "«6 i - P W2.9if.W2.9 g Til K £L |J_ Welded Wire 0 i —fabric hoop

1/2 1 ..\ j£—7f ^ T \ Po>ystyrer" » £J (3 2-0* Dia. '"""H R" ' PCG Fooling r~ \r~ • • •— • • c 1 ' i • x~ r— *. *\ I *

Form socket in concrete to receive 6" x 8" post or place concrete around 6" x BH post wrapped with one layer of li2" thick expanded polystyrene foam wheeling. Do not nail polystyrene to post. Post (o be centered in concrete footing.

Note: Use this detail only by approval of HQ Traffic Safety Devices Branch Chief TRAFFIC SAFETY SYSTEMS GUIDANCE 42 0 3-2019 Figure 14a: Adjustable Height W-beam (2 Hole Post)

Midwest CiuardrEil

Install in LtolLorn Mete

V I iiz :- E: - 30"- 32" i

Edge of Shoulder

• MldwiKt Guardrail Initial Installation

Raise DICCK and rail to - uf.rjer I".": JH t:. provic'e proper =•:•• the new surfacing

29" - 32" SEE MOTE 3 Overlay VW777, .dgs of Shoulder

Adjusted Rail Height

NOTES:

1. All holes in wood posts and blocks

shall be %" diameter ±Jf6" 2. For additional derails, see Standard Plans 3. See Standard Plans for wood or steel post :_f Tf dimensions. 2-Hole Post Detail TRAFFIC SAFETY SYSTEMS GUIDANCE 43 0 3-2019 Figure 14b: Adjustable Height W- beam (3 Hole Post)

Metal Beam Guardrail

Install In Bottom Hole

P'xB'xe1 Post—i

Edge of Shoulder

Metal Beam Guardrail Initial Installation

Raise block and rail to a hole tliat will provide proper height above the new surfacing

Overlay

Edge of Shoulder

8" Adjusted Rail Height

MOTES:

S 1 All holes in wood posts and blocks

shall be diameter +}(e" 2, For additional details, see Standard Plans.

3-Hole Post Detail Li.tlnu.n3 LPLJ l HUIE 1 "t " i "^n I TvT' WWtL FF1JE. T PHTTW jjg. IHEETi l

NOTE: — I. THIS DETAI L DOE S NO T 1PPL I T O EX TEBUINAL5 2. THIS DETAI L KI T D E USE D MT H THPI E DE' U LIK E POST REIlSlEflED Cl.CL EHSWEER D'TE

iiTLi^iiarrn^^i£^^^_^^i \ r ' J " 7

.•'-v v •-."••••.•J " .--••.v-v XIHIU> / V

•~mL SPLICE HAIL SPLICE-, I r-ife " i'-i'/i " I 1 , 2 " 13 = era" r^i = 1 n FT' TT* " n —"— I I SE E MOTE 1 and 2 I I 1 1—M—i

E ELEVATION re (/s ^+ o =

BOLT BLOCK TO LINE POST ^ I I I A I UU I 11 DO t.'JT EuLT t-EEil l TM BLOCK AND PU5T ' /j, c'-i" I I f-S" £2. ,ce{ ^3 ~n n

| RAIL ELDENTS SLICED 3T 12'-6" IHTEPVAL5 m , ELEMENT LEjjOIH = I BAIL •0= PLAN ffl »

GROUND LtNE POST POST POST OR SHOULDER Of o czs UNDE R RALILNG ^+ |'| ' II M H

| SE | E MOTE t Oftdj 2 o

fc^j TJKS— • re - V- GROUN LIND E OR SHOULDER ( ii ^+ _L_ I K . I SURFACING UNDER RAIST L ELEUE STATE OF CALIFORNIA Pi U U !_j OBSTRUCTION u u DEPARTMENT OF TRANSPOFIIAIION B. jj& h I SECTION A-A ii 5H]FTED~L~«E~P05T SHIFT POS T DETAIL S FOR IS TTPKiM |m| I in POI ELEVATION MIDWEST GUARDRAIL SYSTEM If is o

NO SCAL E i yj i —1—Rjrn 1 . This detail doe nos t appl y to terminals, transition ors end anchors, 2 . This detai Bal y be used eifh ttirie-beom line potts i. For detail s of eood pos t arm lood mocks use tod conirruo r MGS, see Standard Plan 111.11, — 4. Far detail s af strcl pott use tdo construct M05. se,c Standard SEE . pt|L ELEfE'-T BLW, K «C Plan ATTN2. ••TEEL P?- EaTr FIIEF^ 9. Use tea 1?' • 1-2* nod block smm. F"P ;-\hE-HV l LET^LV. t. use nrtt 6" • I" • i'-i" nod Hock rims . r, use elttier notched toe ord notched plastic block fosr steel post, = Do not intenu black types. /

1 / / Cllr MIL:, I TOMP (if BLKH TTM HE W / / H HI J HUT . Hi I I / / H MIL F'LE % I I / / f [UT STEEL "ASHEP I IED taigcriCr . —t—t f . / , , I I == *-r- _A j | 1rr * 1 A 1 r-^i)—' fes*) j^^AI L SPLIC E •3" HI«D LlkE = RAIL 5PLICEJ • H'lllLtET 6-3" „ 6jvT iF^LhC- RAIL ELEMENTS SPLICE ADT 1 g*-6" INTERVALS rT

RAIL ELEMENT LENGT =H l3'-6!/;" W o" PLAN STEE L LINE POST o 6" ii 12 " I l'-2" NOTCHED OT- WHED = r 1 / PLASTIC BLOCKS / SEE NOTE S AND 6 SECTION A-A Tit ic u won LM o T*Q 12 WM BLOCK INSTALLAIIOh re e-r- = ! rati n

P aUTTW HEU ) I / / / H T HTH Ht a HUT . KC I / / / - i ONDER G WILIN - SNDER RAILING HEP W PAI F*rL E ^-11/// :"T JTEE L "- IHEF iWffiL»t.»

.B»eFsiEB.nsT , ^jjj j ||' / | * ^ ^ re

: SPPUND LIKE -r ::r -hHILtE T ' 5 UH FACING o A J ' u u u u = — M m SECTIO N A-A SECTIO NB-B TrPICt L STEEL LINE POST TYPICA L STEEL LINE POST Wn,MIlM.MTJS«B WOO D WITH MULTIPLE NOTCHED WOOD P I AN OR NOTCHED PLASTIC BLCOKg OH NOTCHED PLASTIC ULCOKI RAIL ELEMENT, BLOC ANKD 8TEE L POST BOLT PATTERN Ii S SECTION A-A 5TJT E OF CILIFOBBIi iflCAL • Mot LINE POST DEP1FJTUEN T OF TR1MSPORT1TI0N • ifct t 8 " tOOB BLOCK CONTICWIATlai MULTIPLE BLOCK-OUT DETAIL SFO R St. Hirt. J MIDWEST GUARDRAIL SYSTEM I 3

MO SCALE Ca S3S I mm: I P UJLLl ILILLII ISI1L| 2

NOTESI era" P DF POST ^--TOP OF RAIL = I. Re-far to Revised Standard Plant RSP 47TL1 and 3 BLOCK—„ r-6" » 12" * l'-2" / H EC-[ITER ED r[V]L ENGINEER DATE if/" R5F A77L? for camponenf de-t-alI B for IKS not - | J ^ BLOCKS —y j shown on this plan. re

J FLeina aPPROvAL D*TE J 11* 7 "/ I. All posts for any standard barrier run Shall be ~=vf I rSc- C P BUTTON HEAD BOLT PITH r of the same type: Kfcad or £te»*l. k / . Hex NUT OR 5," < HOB i THRE1CED rj; j™^ .> «j:sM«jJ ••• - • V g i_ J = = = = = f BOTH ENFJS, KITH He. NUTS, .Tl<r T-i.. MT-V- ;> *"5rVW.V^ * \ Kit*/ !. Refer to Revised Standard Plan RSP AT7R2, Type 15fi Layout, of 1 \ UT- E-.pviED THFEiL'i -FTEF I "-- J • • ^ P .V ftWEiWH BUHB ^^J^^^ = ^ ^ > NUT[S) TIGHTENED. ND WA5HEH ON for doufrl* MCS connection t* DitoTl A. i g" BAIL FAOE'j FOR BOLTED CONNECTI — C. Iris+all po*+a Id Ban. is _J ..." * t TO LINE POST o ^(HOUND LINE ex H *i E3 SECTION A-A TYPICAL DOUBLE MIDWEST S-" GUARDRAIL SYSTEM

WIN J [ BL0C" BLOCKS I £ I II ! I 1

3 -

PLAN ^ re

3 63

DOUBLE UCS I 2*'- b- I SEE hOTE I DOUBLE MBGR v. rjjT | Y-WI" | i sj-jr i i^r =

.' ^ c M n - i a " o =n

©" E3 ELEVATION »-r- o TRANSITION DETAI L FOR 27%" CRASH CUSHION O TO DOUBLE MIDWEST GUARDRAIL SYSTEM HO SCALE I ; rT £ ill Rlg-ti ftjM r»mi

D = DISTANCE, GB TO FACE OF RAIL MEASURE HEIGHT TOP OF RAIL H = HEIGHT AT FACE OF RAI L FROM FROM EXTENDED LINE ,BASED ON D H = 31" TV- FOR MGS H = 29" +/- F0 3MBCR

) 2? :: SEE NOTE 2 trcT = D CD 1 00

re as GRADE BREAK {GB) 3 a CTQ* =r £ re NOTES as NOTE 1: WHEN THERE IS A GRADE BREA K WITHIN c A%-B% IN FRONT OF TH EW-BEAU. THE HEIGHT re WILL HE DETERMINED BY THE ENGINEER. (DUE TO POTENTIA LTRAJECTORY CONCERNS) 3 re NATE 2: PLACE RU 6RAI L(GUARDRAI ELEMENTL ) E3 AN!) ATTACH TO POS TWITH NO 3LOCK WHEN THE HEIGHT OF GUARDRAIL [MORS E THAN 2^ ABOVE THE STANDARD PLACEMEN HEIGHTT . CONSTRUCTION DETAIL SHOULDER SHOUL DTYPICALL YDRAI NAWAY FROM THE ROADWAY. (THI SIS ESPECIALL YTRUE IN SNOW AREAS) UMikLhi or mim'VTiiiM HIGH SID EOF SUPER IS A CHALLENGE. MIDWEST GUARDRAIL SYSTEM MEASURE HEIGHT DETAIL WHEN THERE IS A GRADE BREAK IN FRONT OF GUARDRAIL AT GRADE BREAK MEASURE HEIGHT OF GUARDRAIL BASED DISTANCON EFROM W SCALE GRADE BREAK TO ADJUST FOR TRAJECTORY TRAFFIC SAFETY SYSTEMS GUIDANCE 48 0 3-2019

Topic 04 – Median Barrier Collision Study Warrant The following collision study warrants are appli- 4.1 Purpose cable to freeways, expressways, and conventional highways with four or more lanes: The purpose of median barriers is to reduce • A collision study warrant for any severity is the risk of an errant vehicle crossing the median met if a location has three or more cross-me- and colliding with opposing traffic. A cross-me- dian collisions and a total cross-median colli- dian collision is defined as one in which an errant sion rate of at least 0.5 collisions per mile per vehicle crosses the median of a highway with four year in a five year period, or or more lanes and strikes, or is struck, by a vehi- • The Fatal collision study warrant is met if a cle from the opposite direction. location has three fatal collisions or more and a fatal cross-median collision rate of at least 4.2 Function 0.12 collisions per mile per year in a five year period. Median barriers are designed to reduce the risk of an errant vehicle: Highway locations with four or more lanes satisfying either of the above collision warrants • Colliding with a vehicle traveling in the op- should be studied. The collision warrant for two- posite direction, or three-lane highways is based on the above fatal • Being deflected back into the traffic stream study warrant criteria only. traveling in the same direction, or, • Decelerating beyond tolerable occupant lim- Freeway Traffic Volume/Width Study Warrant its. The freeway median barrier volume/width study warrant, illustrated in Figure 19, has been While median barriers are capable of pre- developed through an extensive study of freeway venting nearly all cross-median collisions, they cross-median collisions. The need for a median are a fixed object and their installation can result barrier should be considered on freeways when- in collisions that might not otherwise occur. ever the volume and median width plot in the gray area. The probability of an errant vehicle crossing 4.3 Barrier Types the freeway median and colliding with an oppos- ing vehicle is low when either one or both of the The approved standard types of median bar- following conditions exist: riers for new installation are: • The Annual Average Daily Traffic is less 1. Concrete median barrier (Type 60M series), than 20,000, or 2. Thrie Beam barrier (single or double), • The median width is more than 75 feet. 3. Cable barrier (three or four strand), and 4. Portable Concrete Barrier (PCB) (Type K Use of Study Warrants and Type 60 K, for interim use only. 1. Freeways: A freeway is defined as a divided arterial highway with full control of access More information on the different types of and with grade separations at intersections. median barriers is located in Topic 4.5. The Highway Safety Improvement Program Guidelines, Chapter 4, Section 4.1.2.1, titled 4.4 Study Warrants “Multilane Cross Median Collision” provides guidance for study warrants. The collision study warrant and freeway vol- Freeway locations without median bar- ume/width study warrant are used to identify lo- rier are to be studied when the collision or cations for investigation. These study warrants, volume/width study warrant is met. The need their uses and limitations are described below. for a median barrier should also be studied TRAFFIC SAFETY SYSTEMS GUIDANCE 49 0 3-2019 when building a new freeway or when adding All studies, and any changes to the studies, a lane to an existing freeway. must document the decision to install or not If the median barrier volume/width study to install a median barrier on the freeway sys- warrant will be met within five years of com- tem. The District Traffic Safety Engineer pletion of construction, then the feasibility of must approve the decision to install or not in- placing a median barrier should be consid- stall median barrier, and any changes to the ered. studies and the decision must be documented in the project files.

Figure 19: Freeway Median Barrier Study Warrant

TRAFFIC SAFETY SYSTEMS GUIDANCE 50 0 3-2019 2. Expressways: An expressway is defined as an Median barriers may be an appropriate so- arterial highway with at least partial control of lution to cross-median or cross-centerline colli- access, and which may or may not be divided. sions on multilane conventional highways. Expressways normally do not have grade sepa- Multilane conventional highway locations are rations at intersections. to be studied when the collision study warrant Expressway locations are to be reviewed is met. The freeway volume/width study war- when the collision study warrant is met. The rant, although developed for freeways, may be freeway volume/width study warrant, although used to study multilane conventional highways developed for freeways, may be used for stud- as a proactive measure for installation of a me- ying expressways as a proactive measure for dian barrier prior to appearing on the cross me- the installation of median barrier prior to ap- dian collision warrant list. pearing on the cross median collision warrant Installation of a median barrier on mul- list. tilane conventional highways may not be feasi- ble due to the numerous issues presented in the For new construction, and when upgrading note under Expressways. The District Traffic from a conventional highway to an expressway, Safety Engineer may consider installation of a if there are less than five year of existing colli- raised median or buffer, with a 6-inch dike or sion data the District Traffic Safety Engineer curb and gutter, to reduce cross centerline col- must be consulted to determine if a study lisions on urban or suburban facilities operating should be conducted to install median barrier. at 45 mph or less. Any decision to install or not to install a median 4. Two- and Three-Lane Conventional Highways: barrier must be documented in the study. Two- and three-lane conventional highways are defined as highways without control of access,

and where property owners have a right to ac- Note: Access openings on expressways, cess highway facilities with driveways, and multilane conventional highways and two-lane there are at-grade intersections. The Highway and three-lane conventional highway facilities Safety Improvement Program guidelines, present sight distance issues with respect to in- Chapter 4, Section 4.1.2.2, titled “Two- and stallation of a median barrier. All access open- Three-Lane Cross Centerline Collision”, along ings must be analyzed to maintain both corner with Deputy Directive 50, provide guidance on sight distance at approach intersections and study warrants and median barrier policy for stopping sight distance on the specific facility two- and three-lane facilities, respectively. types themselves (see the Highway Design Installation of a median barrier on two- and Manual for sight distance standards). three-lane highways is rare, and requires analy- Some of the issues to consider in the study sis of the issues presented in the note under ex- include but are not limited to the following: pressways above. In addition, consideration is • Collision history to be given to the fact that a median barrier will • Travel speed on the facility eliminate any passing zones and may impact • Out of direction travel and turn around emergency vehicle response within the bar- points for the abutting property owners, rier’s limits. • Accommodation for design vehicles to turn Note: Due to operational and environmen- around tal considerations, right of way purchases, im- • The need for crash cushions where the me- pacts to the abutting property owners of the dian barrier stops adjacent to travel state highway and other considerations, incre- mental improvements should be considered on 3. Multilane Conventional Highways: A multilane two- and three-lane conventional highways. conventional highway (two or more lanes in These incremental improvements include, but each direction) is defined as a highway without are not limited to: barrier striping, rumble strips control of access, where property owners have on the outside paved shoulder, shoulder widen- a right to access highway facilities with drive- ing with rumble strips, centerline buffer zones, ways and at grade intersections. These high- rumble strips on the centerline stripe, surface ways may or may not be divided. mounted channelizes on a centerline buffer zone, and other appropriate devices and appli- cations. TRAFFIC SAFETY SYSTEMS GUIDANCE 51 0 3-2019 4.5 Criteria for Choice of Type All median barrier offset dimensions are measured from the edge of traveled way to the bottom face of After the decision to install permanent median barrier.) barriers has been made, Table 7, Median Barrier Any exceptions to the barrier type selection cri- Type Selection Table, is to be used to determine the teria listed in Table 7 must be approved by the appropriate barrier type at a given location. (Note: Headquarters Traffic Safety Systems Branch.

Table 7: Median Barrier Type Selection

Median Width Equal to or Greater than Equal to or Equal to 46 ft to less than 36 ft to less than Greater than less than 60 ft 36 feet (ft) 46 ft 60 ft Consult HQ Type 60M Type 60M concrete, Thrie beam Safety Systems Type concrete1 Thrie beam or cable3 or cable3 Branch NO PLANTINGS 2 Offset up to 17 ft On centerline Consult HQ Traffic and pave up to it, or Placement pave up to face Safety Systems on centerline On centerline of barrier Branch (no paving)

Barrier Type 60M Type 60M concrete Thrie beam Thrie beam Type concrete1 or Thrie beam

PLANTINGS On each side of Consult HQ Traffic On each side of On each side of Placement planting, pave Safety Systems plantings, minimum plantings, minimum up to the barrier Branch offset 17 ft offset 17 ft

1Obtain approval from the District Maintenance Engineer for using thrie beam barrier. 2Except when offset for barrier openings. 3 Cable barrier requires approval by the Deputy District Directors of Traffic Operations and Maintenance.

Each barrier system has properties that make a sheet metal at severe impact angles. The sever- certain type of barrier better suited in one location ity of impact may be greater with concrete than than another. These characteristics are: with thrie beam barriers at high impact angles. Because impact angles tend to increase as the 1. Concrete Barrier: The Concrete Barrier distance to the barrier increases, the use of con- Type 60M series is the current standard and crete median barrier is guided by Figure 19 and shall be used when concrete barrier is to be Table 7. For median widths equal to or less than constructed (see the Standard Plans). The 36 feet, concrete barriers are the preferred bar- Type 60M series is to the current MASH stand- rier type. ards. This barrier is rigid and does not deflect Concrete barrier requires little mainte- upon impact, but dissipates impact energy nance; consequently, traffic is not disrupted by within the vehicle suspension system at shallow extensive maintenance operations, and mainte- angle impacts and by displacement of vehicle nance workers are not exposed to large volumes TRAFFIC SAFETY SYSTEMS GUIDANCE 52 0 3-2019 of relatively high-speed traffic. Concrete bar- higher maintenance costs. Vegetation control rier have the highest percentage of unreported may be considered beneath thrie beam barrier, collisions. In shallow angle collisions with con- and details are in the Standard Plans. If an aes- crete barrier, most vehicles are redirected with thetic appearance for thrie beam barrier ele- minimal damage and can be driven away. Also, ments is desired, refer to Topic 3.6(10)(g), Aes- concrete barrier has no projections to collect thetic Metal Guardrail Treatment, for options. debris. For new installations of thrie beam bar- If an aesthetic appearance for concrete bar- rier, a minimum distance of 17 feet between rier is desired, they need to have been previ- the face of rail and the edge of travel way ously crash tested and cannot reduce the shall be provided for maintenance activities. amount of concrete over the reinforcing bars If the 17 feet distance cannot be provided due found in the Standard Plans. Furthermore, the to plantings, concrete barrier should be placed aesthetic treatments must not have protrusions instead. or indentations 1 inch or greater. If there are Thrie beam barriers may also be installed then they must be above 48 inches from the in medians where there is a history of sand ac- base of the barrier or, 72 inches if integrated cumulation the median due to high wind, or in with a wall structure (Also See HDM, Section designated Federal Emergency Management 210.5 Aesthetic Consideration). Agency floodplain areas. Refer to Table 7 for Use of Aesthetic Treatments to concrete requirements for exceptions where thrie beam barriers must be concurred by the District Traf- barrier is necessary under these conditions. fic Safety Engineer. At the time of publication, October 31, For more on Aesthetic Barrier Treatments, 2019, is when all Thrie Beam Barrier will have and the options, refer to Landscape Architec- to meet MASH standards. ture, Highway Barrier Aesthetics, at: 3. Cable Barrier: Three or four-strand cable bar- http://www.dot.ca.gov/hq/Land- rier is a flexible barrier and may be placed in Arch/16_la_design/aesthetics/barriers/in- wider medians with no plantings. Although lower in cost than concrete or thrie beam bar- dex.htm rier, cable barrier experiences large deflections

upon impact. Approved high tension cable bar- Concrete barriers must not be used as re- riers may be considered for medians 46 feet or taining walls and are not to be constructed for wider. this purpose. Furthermore the Type 60C con- At the time of publication, October 31, crete barrier can only be placed along roadbed 2019, is when all Cable Barrier will have to structural sections and must not be placed along meet MASH standards. or on soil. If appurtenances are needed on top of con- Installation of any new cable barrier must crete barriers, such as steel sign posts, refer to be approved by the Deputy District Directors of Topic 3.2(2) for guidance and restrictions. Traffic Operations and Maintenance Proposed appurtenances on top of concrete 4. Portable Barrier: If there is widening or other barriers, such as steel sign supports or chain type of work that will reposition barriers in five link fence, must be approved by the District years or less, consider a Portable Concrete Bar- Traffic Safety Engineer and documented in the rier (PCB), such as Portable Concrete Barrier project files. (Type 60K) or Temporary Railing (Type K), as 2. Thrie Beam Barrier: Thrie Beam barrier is an interim barrier. This applies to all median the current standard and shall be used when widths with or without plantings. Cases in metal median barrier is to be constructed which an interim barrier may be used include (see the Standard Plans). This barrier is semi- stage construction where a PCB is left in place rigid and may deflect up to 2 feet on impact, after project acceptance, a programmed project providing some dissipation of energy through to construct permanent median barrier and a the displacement of posts and flattening of bar- programmed project in the State Transportation rier elements. Thrie beam barrier can sustain Improvement Program (STIP). The project minor impacts without requiring immediate which repositions the barrier shall include the and extensive restoration work. This barrier cost of installing the permanent median barrier. system is wider than concrete barrier, and has TRAFFIC SAFETY SYSTEMS GUIDANCE 53 0 3-2019 Another type of portable barrier are Porta- barrier (see Standard Plans for details). Vari- ble Steel Barriers (PSB). These systems may ous modified barriers details, which are not part have retractable wheels so that the can be easily of the Standard Plans, such as the Type 60SD moved, be light in weight, and may have gate for covering only one side of a row of columns sections that can be installed with the system and Type 60R used for minimum shoulder for passage of equipment. These system are width, can be found on the Structures XS proprietary and can be found on the Traffic Sheets. The use of these nonstandard barriers Safety Devices Approved Products site: are only done by weighing all the engineering http://traffic.onramp.dot.ca.gov/safety-de- parameters and must not be used to only pre- vices-approved-products . serve shoulder width without any other consid- Approved safety end treatments such as in- erations. All modified barriers require the ap- ertial barriers (sand barrels) must be used in proval of both the District Traffic Safety Engi- conjunction with the PCB to shield the ap- neer and the Headquarters Traffic Safety Sys- proach ends of the barrier. Refer to the Standard tems Branch and the Exception to Traffic Plans for PCB staking details and conditions of Safety System Standards to be completed. use. The Type 60M concrete barrier is normally The interim PCB offset distance must be constructed by slip-forming without a footing approved by the Headquarters Traffic Safety on pavement. Ends of the barrier at gaps or Systems Branch. In addition, use of the PCB contraction joints where the concrete and rein- exceeding five years must be approved by the forcement is not continuous requires a 10-inch Headquarters Traffic Safety Systems Branch. deep by 10-foot long footing under the end of At the time of publication, October 31, the barrier. This is intended to prevent displace- 2019, is when all Portable Barrier will have to ment of the barrier in an impact at the end. For meet MASH standards. runs of Type 60M barrier that are 1000 feet in length or longer a footing may be added every 500 feet to minimize displacement of the bar - rier. Concrete barrier footings must be in pave- ment. The pavement must extend a minimum 4.6 Barrier Design Details of 1 foot beyond the concrete barrier footing or constructed monolithically with the concrete The details for each type of barrier installed footing. (see Figure 8). Other versions of the in medians are background for the criteria used Type 60M series concrete barriers usually re - in the selections of those types. This topic pro- quire fixed forms for construction. Concrete vides the details of those barrier designs. barriers must be on pavement or well com- pacted base. 1. Concrete Barriers: Construction details for Pavement overlays can compromise the concrete barriers are shown in the Standard performance of existing concrete median barri- Plans. The Concrete barrier Type 50 series, ers. Formerly, Type 50 concrete barrier could with its “Jersey-style” sides and a height of tolerate the addition of 3 inches of pavement 32 inches, was the standard concrete barrier for against its base, reducing its effective height to many years. It has been replaced by the single 29 inches, without replacement of the barrier. slope concrete barrier Type 60M series, with With the full adoption of MASH the minimum the Type 60M having a height of 42 inches and height of single slope concrete barrier is 36 a constant slope on each side. With the full im- inches per Table 6. The Type 60MS series can- plementation of MASH the minimum height of not tolerate overlays of pavement that would re- Type 60MS is 36 inches and must be main- duce the effective height to not less than 36 tained. If glare screen is required, the 56-inch inches without replacement of the barrier per tall Type 60MG concrete barrier is to be used. Table 6. Where overlays are planned, the de- Refer to Topic 4.9 for more information about signer needs to be cognizant of what the exist- use of glare screens. With the adoption of the ing and end result effective barrier height will MASH standards the use of Type 60S series is be. If the end result height is less than 36 inches, no longer allowed. The Type 60MP, Type replace with new barrier for all projects except 60PR and Type 60AP concrete barrier series those overlaying 0.15 feet (2 inches) or less. are for installing steel sign post on top of the For those projects, taper the pavement cross TRAFFIC SAFETY SYSTEMS GUIDANCE 54 0 3-2019 slope to no steeper than 10:1 to maintain the the Department’s Pre-Qualified Products List barrier’s effective height, if feasible. for Highway Safety Features. 2. Thrie Beam Barrier: Construction details for 4. End Treatments: All blunt ends of median bar- Thrie Beam barriers are shown in the Standard riers are fixed objects and need to be shielded. Plans. Thrie beam barrier is a corrugated galva- This may be done by flaring the end of the bar- nized steel beam, nominally 20-inch wide by rier away from approaching traffic or placing 3¼-inch deep, mounted on wood or plastic an appropriate crash cushion at the approach blocks fastened to wood or galvanized steel end of the barrier. Sloping ends, or ends that are posts. The top of the barrier element is 32 turned down into the ground, must not to be inches above the surface at the face of the bar- constructed. rier. Line posts must not be installed in struc - tural pavements that would restrict movement 4.7 Median Design Considerations of the posts during impact, also see Section 3.6(8). The ends of thrie beam barrier are an- Many of the issues encountered with irregular chored to ensure proper performance. medians or continuous obstruction in the median Where larger posts are required in transi- can be mitigated by the following considerations: tions approaching fixed objects, refer to “Thrie 1. Longitudinal Median Dikes: The restrictions Beam Barrier at Fixed Objects in the Median” for use on the placement of curb or dike in front in the Standard Plans for more details. of barrier are as followed: Where transitions are needed to concrete • Thrie Beam Barrier: When required, the bridge barriers, the single thrie beam barrier dike should be as close to the thrie beam transition railing (Type STBB) and double thrie barrier as possible. If six-inch high dike is beam barrier transition railing (Type DTBB) needed with thrie beam barrier, the dike are used. Refer to the Type STBB and Type may be placed under the barrier but the DTBB transition railings in the Standard Plans front edge of the dike shall not be more for more details. Where a transition is needed than seven inches in front of the face of to Type 60M concrete median barrier, refer to the barrier. Dikes over two inches high “Double Thrie Beam Barrier Connection to shall not be placed between seven Concrete Barrier” in the Standard Plans. inches and 13 feet in front of thrie beam Where a double-faced thrie beam barrier is barrier. proposed to accommodate cross-median drain- • Concrete Barrier: Dike must not be placed age and a saw-toothed median section requires in front of concrete barriers. the rail elements to be mounted at different el- • Cable Barrier: Cable Barriers are proprie- evations, the thrie beam elements on the lower tary systems. If dike is needed then install roadway shall be used with 6-inch x 12-inch x dike per manufactures recommendations. 22-inch blocks. Approval must be obtained 2. Median Ditches: Drainage ditches should be as from the Headquarters Traffic Safety Systems shallow and as flat as possible. Where deep Branch. ditches are unavoidable, a barrier may be needed on both sides of the ditch. See the Road- Steel posts shall be used for the construc- side Design Guide, Chapter 6, for recom- tion of a saw-toothed median section. Field mended barrier placement. drilling a second pair of holes parallel to each 3. Median Drainage: Thrie beam barrier is adapt- other and the original pair should not be done. able to most median drainage conditions. 3. Cable Barriers: The approved high-tension ca- Where thrie beam barrier crosses a drainage in- ble barriers are three- and four-strand types and let and one or more posts are installed within are proprietary. These systems are pre- the depression or swale, a rub rail may be stretched prior to installation. The deflections needed. The rub rail prevents a vehicle from of the high-tension barriers are typically 6 to 12 snagging the post with a wheel and spans the feet but are dependent on post spacing. These length of the depression or swale See Figure 14. systems may be considered for permanent use Concrete median barrier, however, may re- in medians according to Table 7 . The condi- quire special designs to provide drainage. Slot- tions for use and the design details (which vary ted drain inlets are the recommended means of between the approved systems) are available on providing drainage in paved medians with con- crete median barrier. Design details for slotted TRAFFIC SAFETY SYSTEMS GUIDANCE 55 0 3-2019 drains are contained in the Standard Plans. can affect barrier performance. If median cross Where a concrete barrier spans or crosses an slopes are greater than 10:1, refer to the Road- existing drainage inlet, special barrier gap clo- side Design Guide, Chapter 6, for recom- sure details are available. Passing runoff under mended barrier placement. a concrete median barrier with scuppers on an To ensure desired barrier performance, the all-paved cross section is not advisable. What relationship between median and traveled way was sheet flow becomes concentrated flow cross-slopes must be checked using the proce- across the lower roadway. Scuppers, if used, dures outlines in Traffic Bulletin No. 15 and ap- should not extend higher than 3 inches at the proved by the District Traffic Safety Engineer. base of the barrier. Also, each scupper should The approval must be documented in the pro- be no more than 3 feet long and a series of scup- ject files. pers should not occupy more than 25 percent of 9. Adding Lanes in the Median: Where lanes are any 20-foot length of concrete barrier. added in the median, thereby reducing the me- The District Traffic Safety Engineer must dian width, the median barrier type to be used approve the decision to install scuppers. The is selected in accordance with Topic 4.5, Crite- decision must be documented in the project ria for Choice of Type. In some cases it will be files. necessary to evaluate the need to upgrade or re- For additional discussion of median drain- place existing non-concrete barrier. Costs asso- age, see the Highway Design Manual, ciated with upgrading the barrier type shall be Index 834.2, Median Drainage. included in the preliminary scoping document 4. Raised Medians: Median barriers should not be estimate. placed on raised medians. For proposed or ex- 10. Structure Approach: Where traffic is one-way, isting median barrier on a raised median, the approach speeds are less than 45 mph, and thrie barrier should be flush with curb face and the beam barrier connection to bridge curb or side- barrier height is measured from top of curb. walk is needed, Figure 21 may be used. 5. Flat Medians: On paved medians, 10:1 cross 11. Effective Barrier Height: Overlay and reha- slope or flatter, the barrier height is measured bilitation projects, including any mainte- from the paved surface exclusive of any local- nance activities, which will impact existing ized ditch surface. Consideration should be barriers, shall include required actions in given to paving medians adjacent to concrete accordance with the guidelines in Table 6, barriers to reduce maintenance activities. See Barrier Restoration Practice. If an overlay the Highway Design Manual, Topic 305.5 for results in a barrier height out of the paving requirements. indicated tolerances, then the barrier shall 6. Planted Medians: Where plants are located in be reconstructed or replaced. The standard the median and the plantings cannot be re- heights and tolerances listed in Table 6 for each moved, two barriers, one on each side of the type of barrier are recommended limits based plants, shall be placed. See Topic 4.5, Criteria on crash test performance. for Choice of Type, to determine if the use of 12. Wildlife Passageways: Openings in concrete concrete or thrie beam barrier is appropriate. barriers for animals should be considered if rec- Existing earth berms used with median plant- ommended by district environmental staff. See ings are to be eliminated. 7. Future Construction: Where traffic lanes are to be added to the median within five years of bar- the Standard Plans for details of wildlife pas- rier construction, the median grade line should sageways in concrete barriers for small, me- be adjusted and the barrier installed for the ul- dium and large animal. timate condition. If it is not practical to do this, The District Traffic Safety Engineer must ap- concrete barrier should not be used since, un- prove the decision to wildlife passageways. The like the other barrier types, the height of con- decision must be documented in the project crete cannot be readily adjusted. files. 8. Median Cross-Slope: Where median cross- slopes are greater than 10:1, vehicle trajectory TRAFFIC SAFETY SYSTEMS GUIDANCE 56 0 3-2019

Figure 20: Thrie Beam Barrier Rub Rail Detail

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(Some shape as thrie bean roil element. Required when thrie beam roil is attached to bridge rail trig with metal box spacer ond terminal section not used). TRAFFIC SAFETY SYSTEMS GUIDANCE 58 0 3-2019 provided where the median is less than 22 4.8 CHP Enforcement Areas / feet wide, and motor vehicle emergency pas- Emergency Passageways sageways are typically not provided where the median is 32 feet or less in width, unless Except for CHP enforcement areas/emer- there are unusual circumstances. gency passageways in median barriers, median 5. Barrier Design Details: Designs for barrier openings are not allowed on freeways. The use emergency passageways are shown under of passageways are to be kept to a minimum and Emergency Passageways in the Standard carefully located to provide adequate stopping Plans. sight distance to and from the opening along the 6. CHP Enforcement Area: For CHP enforce- freeway. Emergency passageways may be ap- ment area design details refer to the HOV propriate for highway patrol vehicles, emer- Guidelines at: gency service vehicles such as tow trucks, am- http://www.dot.ca.gov/hq/traf- bulances, firefighting apparatus and maintenance fops/trafmgmt/hov/files/hov_guide- equipment. Emergency openings in glare screens lines/HOV%20Guideline.pdf for passage of stretchers or personnel are cov- ered in Topic 4.9. 4.9 Glare Screens and Type 60MG The need for CHP enforcement areas/emer- Concrete Barrier gency passageways and their locations must be established by the District Traffic Safety Engi- Glare screens are designed to screen out the neer in cooperation with the local Department of headlight glare of opposing traffic. Glare screens Highway Patrol office, fire district and emer- may be considered on new or existing median gency services. The decision must be docu- barriers where the median is 22 feet or less in mented in the project files. width. Glare screens are typically not installed in Where emergency openings are provided, medians wider than 22 feet. they are to be designed based on the following On narrow medians of 36 feet or less the considerations: standard Type 60MG concrete barrier that is 56- inch tall, may also be used to give additional 1. Types of Vehicles: Emergency passageways clearance for pavement overlays even when are designed for motorcycles or for motor headlight glare of opposing traffic is not a con- vehicles. Openings for motorcycles are 6 cern. The decision to use Type 60MG, must be feet to 8 feet long, and openings for motor approved by the District Traffic Safety Engineer vehicles are 12 feet to 16 feet long. when the need for the use of Type 60MG on fa- 2. Types of Passageways: Permanent openings cilities where pavement overlays are likely, and and temporary openings with removable a reduction in the effective height of the barrier sections of barrier are the two types of emer- is expected over time. gency passageways used. Emergency pas- All other uses of Type 60MG and glare sageways may be either temporary, remova- screen may only be installed where an engineer- ble sections of barrier or permanent open- ing evaluation shows it would be of overall ben- ings where the barrier ends are offset away efit to the motorist considering the cost and from approaching traffic. All temporary other impacts of the glare screen. Engineering openings are to be closed immediately after evaluations should consider glare due to the use. combined effects of grades, horizontal align- 3. Spacing of Passageways: Access to the op- ment, traffic volumes, as well as any public posite side of the freeway may be provided complaints. by a combination of ramps and Where glare is determined to affect safety emergency passageways. Emergency Pas- performance and glare screen is not cost-effec- sageway shall not be placed at less than tive or creates impacts that cannot be mitigated, three mile intervals. highway lighting should be considered to reduce 4. Median Widths: The median needs to be the level/intensity and effects of headlight glare. wide enough to accommodate turning vehi- On route segments with scenic views, the sensi- cles safely and contain the barrier with any tivity of the public to the blocking of these views necessary tapers. Therefore, motorcycle should be considered. emergency passageways are typically not TRAFFIC SAFETY SYSTEMS GUIDANCE 59 0 3-2019 Topic 5 – Outer Separation Barrier Glare screen and Type 60MG concrete bar- rier must be approved by the District Traffic 5.1 Introduction Safety Engineer and must be incorporated in the project between the project initiation docu- The need for outer separation barrier be- ments to the PS&E when it is determined to be tween a freeway and a should be need. considered when there are concerns regarding Based on an engineering evaluation, glare collisions of vehicles crossing these separated screens may be installed on segments or spot lo- facilities. Installation of an outer separation bar- cations along frontage roads. Chain link fence rier is generally studied at locations where the with slats may be appropriate in these situations. freeway volume/width warrant or the collision warrant is met. Refer to Topics 4.4 and 5.2 for Glare screens are subject to the following con- more information about these study warrants. siderations:

1. Thrie Beam Barrier: Glare screen is not gen- 5.2 Outer Separation Barrier Criteria erally used with thrie beam barrier. The following criteria shall be satisfied 2. Concrete Barrier: When glare screen is de- for installation of outer separation barrier: termined appropriate, the standard perma- nent glare screen is the 56-inch tall 1. The direction of travel of the frontage road Type 60MG concrete barrier due to its re- opposes freeway traffic, and sistance to damage. 2. The opposing frontage road traffic volume is greater than or equal to 5,000 annual aver- 3. Emergency Openings: When glare screen is age daily traffic (AADT), and included with the barrier, openings may be 3. The location meets the criteria described in provided at approximately 600-foot intervals Figure 11: Freeway Median Barrier Study if requested by local emergency agencies. In Warrant. Use the distance from the freeway areas with above average edge of traveled way to the frontage road rates, openings may be spaced at 300-foot edge of traveled way for the width, and for intervals. Spacing may be varied to provide the traffic volume, use one-half the freeway such an opening at each structure crossing AADT plus the opposing AADT on the over the highway. frontage road. Or: 4. If a location does not meet the above three Glare can also be reduced by the addition of criteria, but can be shown to meet either of highway lighting. This can be done by median the two criteria below, then a barrier may be lighting or high mast lighting. Medial lighting recommended if: can be combine with Type 60MG concrete bar- rier. a. A collision study warrant for any sever- ity is based on a location having three or 4.10 Delineation more collisions involving frontage road and freeway vehicles, and a total front- To provide enhanced delineation, approved age road and freeway collision rate of at retro-reflective units may be placed on thrie- least 0.5 collisions per mile per year in a beam and concrete barrier for narrow medians five year period, or 36 feet wide of less. When the clearance from b. The Fatal collision study warrant is the barrier to the edge of traveled way is less based on a location having three or more than 12 feet the barrier should be delineated. For fatal collisions involving frontage road further details regarding delineation and place- and freeway vehicles, and a fatal front- ment on median barriers, refer to the Standard age road and freeway collision rate of at Plans and the California MUTCD. least 0.12 collisions per mile per year in a five year period. TRAFFIC SAFETY SYSTEMS GUIDANCE 60 0 3-2019 Topic 6 – Crash Cushions Copies of the Summary of Quantities and applicable Layout Sheets from the Project Plans 6.1 Purpose may supplement the documented statement of concurrence in the project files. Crash cushions, also known as impact attenua- As of, October 31, 2018, new installations of tors, are intended to shield fixed objects that Crash Cushions will have to meet MASH stand- cannot be removed or where other protective ards. system such as guardrail and not suitable. When a vehicle strikes a crash cushion it decelerates by the transfer of inertia in displacing sand or wa- 6.4 Temporary Crash Cushions ter, expending kinetic energy through compress- ing a hydraulic cylinder or collapsible material, Temporary crash cushions can be practical tearing metal, or moving a metal cable or strap in construction staging where temporary fixed through a restricted path. objects are shielded, such as Temporary Railing systems such as guardrail are not suitable. When 6.2 Available Crash Cushion Types a vehicle strikes a crash cushion it decelerates by the transfer of inertia in displacing sand or wa- The types of crash cushions currently availa- ter, expending kinetic energy through compress- ble include several mechanical systems previ- ing a hydraulic cylinder or collapsible material, ously mentioned, arrays of sand-filled plastic tearing metal, or moving a metal cable or strap drums, and water-filled modules. These types through a restricted path. vary in regard to costs of installation, size, ease (Type K or Type 60K). Proprietary crash of repair and maintenance. These aspects should cushions have been developed that use expedient be carefully evaluated in order to select an ap- methods for installation and removal, such as propriate crash cushion or equal alternatives for base plate mountings for the attenuators with a location based on site geometrics, anticipated pre-drilled holes for pavement anchor rods or repair and maintenance effort. For more infor- stakes. These features are useful for moving at- mation on which crash cushions are MASH ap- tenuators between locations and typically allow proved for use on California State Highways, anchorage in existing pavements. When using contact your District Traffic Safety Systems Co- crash attenuators with Type 60 K contact your ordinator or refer to the Authorized Material List District Traffic Safety Systems Coordinator. (AML). Commonly used non-proprietary crash cush- ions are arrays of sand-filled modules. Sand- 6.3 Placement filled modules are lower cost attenuators, but are also more maintenance intensive. Figure 22 Crash cushions are to be installed at fixed shows arrays of sand-filled modules for tempo- objects that cannot be economically removed or rary use on highways in unidirectional travel and made breakaway and where other protective sys- where approach speeds are less than 25 and 35 tems such as guardrail are not suitable, such as mph. See the Standard Plans for details of arrays at the gore point on a separated structure. Crash of sand-filled modules for approach speeds of 45 cushions are also generally used to shield objects mph or greater. such as piers, columns, overhead signs supports, and median barrier installations. 6.5 Severe Duty Crash Cushions Concrete barriers or walls that are taller than shielding crash cushions require modification at Severe duty crash cushions are appropri- the connecting ends of the barriers. The top of ate for high-incidence roadway locations, offer- the wall or barrier should be tapered at maxi- ing superior cost effectiveness and improved mum of 4:1 to meet no more than 1 inch above safety for the traveling public and highway the top of the crash cushion. workers. The crash cushions perform well in The District Traffic Safety Engineer must high-speed frontal and side impact tests, thereby concur with the decision to install or not to in- reducing repair costs and the time needed for re- stall a crash cushion. The statement of concur- pairs. For the current approved list, specific cri- rence must be documented in the project files (see Topic 1.3 for guidance). TRAFFIC SAFETY SYSTEMS GUIDANCE 61 0 3-2019 teria, and guidance of Severe Duty Crash Cush- ions, contact your District Traffic Safety System Coordinator.

6.6 Reusable Crash Cushions

Reusable crash cushions have major components that may survive most impacts and can be salvaged when the crash cushion is being repaired on site. Some of the other components need to be replaced after an impact to make the entire crash cushion crashworthy again. For the current approved list, specific criteria, and guid- ance of Reusable Crash Cushions, contact your District Traffic Safety Systems Coordinator.

TRAFFIC SAFETY SYSTEMS GUIDANCE 62 0 3-2019 Figure 22: Sand Barrel Arrays

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Notes: 1. ## indicates sand filled module location and weight 4. Place theType P marker panel so that the bottom of sand in pounds for each module. Module ofthe panel rests uponthe ground. spacing is based on the greater diameter of the 5. Refe rto Standard Plan A73B for marker details. module. 6. Approach speeds indicated conform to NCH RP 350 2. All sand weights are nominal. Report criteria. 3. Temporary crash cushion arrays shall not encroach 7. Use of pallets is optional. on thetraveledvvay. TRAFFIC SAFETY SYSTEMS GUIDANCE 63 0 3-2019 Dist - Co - Rte - PM Program Code EA APPENDIX A EXCEPTION TO TRAFFIC SAFETY SYSTEM STANDARDS (See Traffic Safety Systems Guidance for definitions and applications) Check One Box DISTRICT APPROVAL REQUIRED HEADQUARTERS APPROVAL REQUIRED

Prepared By:

( NAME ) DATE District Approval By or Recommended By if Headquarters Approval Required:

DISTRICT TRAFFIC SAFETY ENGINEER DATE Headquarters Approval By:

HQ TRAFFIC SAFETY SYSTEMS BRANCH, CHIEF DATE

1. NONSTANDARD CONDITION / FEATURE Briefly describe the nonstandard condition(s), the specific standard(s) and source document (e.g. Standard Plan, Caltrans Traffic Safety Manual, etc.). Specify if the nonstandard feature is an existing condition that will be retained, or if a nonstandard feature will be introduced

2. REASON(S) FOR REQUESTING EXCEPTION Summarize engineering and other reasons that support or justify the deviation(s). Reasons are typically related to the expected vehicle operating speed, major physical constraints (for spot / incremental improvement projects), and engineering analysis related to the expected perfor- mance of the safety system. 3. CONSULTATIONS If relevant, identify other “specialists” who concur with the proposed nonstandard feature / condition.