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HIGHWAY DESIGN MANUAL Chapter 10 Roadside Design, Guide Rail

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HIGHWAY DESIGN MANUAL Chapter 10 Roadside Design, Guide Rail HIGHWAY DESIGN MANUAL Chapter 10 Roadside Design, Guide Rail, and Appurtenances Revision 92 (Limited Revision) March 16, 2020 Issued by Engineering Bulletin 20-018 Effective with Design Approval on or after May 01, 2020 ROADSIDE DESIGN 10-2 Section Changes Throughout Updated references to A Policy on Geometric Design of Highways and Streets to the most recent edition (7th edition, 2018) Throughout Chapter reformatted for improved legibility. The new format links the revision to the issuing document and actual effective date, rather than just the issuing date. Throughout Retitled and renumbered tables and figures as consecutive “exhibits’ and updated references in text. 10.2.2.7 Shielding Added “Bicyclists”; edited and expanded section to include reference of Pedestrians to bollards. and Bicyclists 10.2.2.8 Inserted new Section 10.2.2.8 “Security Bollards” Security Bollards EB 20-018 D.A. 05/01/2020 ROADSIDE DESIGN 10-3 TABLE OF CONTENTS 10.1 INTRODUCTION .............................................................................................................................. 5 10.2 NEW, RECONSTRUCTION, AND FREEWAY 2R/3R PROJECTS ................................................ 6 10.2.1 Clear Zones ............................................................................................................................... 6 10.2.2 Barrier Design Parameters ...................................................................................................... 22 10.2.3 Barrier Types ........................................................................................................................... 46 10.2.4 Median Barriers ....................................................................................................................... 63 10.2.5 Barrier Terminals ..................................................................................................................... 86 10.2.6 Impact Attenuators ................................................................................................................ 104 10.2.7 Developed Area and Large Volume Exceptions ................................................................... 119 10.3 EXISTING FACILITIES ................................................................................................................ 135 10.3.1 Evaluation of Existing Facilities ............................................................................................. 136 10.3.2 Detailed Scope of Work Determinations ............................................................................... 145 10.3.3 Documentation of Roadside Design Process for Upgrading of Existing Facilities ................ 152 10.4 CONSTRUCTION ZONE GUIDANCE ......................................................................................... 156 10.4.1 Temporary Concrete Barriers (TCB) ..................................................................................... 156 10.4.2 Temporary Timber Safety Curb and Median Barriers ........................................................... 156 10.4.3 Dragnets ................................................................................................................................ 156 10.4.4 Moveable Concrete Barriers ................................................................................................. 156 10.4.5 Warrants for Work Zone Barriers .......................................................................................... 156 10.5 SPECIAL TOPICS ....................................................................................................................... 157 10.5.1 Mailboxes .............................................................................................................................. 157 10.5.2 Fencing .................................................................................................................................. 159 10.5.3 Cattle Passes ........................................................................................................................ 165 10.5.4 Guide Posts ........................................................................................................................... 166 10.5.5 Barriers on Dead-End Roads and Streets ............................................................................ 166 10.5.6 Public Relations..................................................................................................................... 167 10.5.7 Resetting Guide Rail ............................................................................................................. 168 10.6 REFERENCES ............................................................................................................................. 172 APPENDIX A - SPOT EVALUATION OF DESIRABLE CLEAR ZONE WIDTHS .................................10-A1 APPENDIX B - SUPPORT OF GUIDE RAIL OVER SHALLOW OBSTRUCTIONS ..............................10-B1 APPENDIX C – BARRIER IMPACT TESTING AND ITS RELATION TO IN-SERVICE PERFORMANCE.......................................................................................................... 10-C1 INDEX .................................................................................................................................................. 10IND-1 EB 20-018 D.A. 05/01/2020 ROADSIDE DESIGN 10-4 LIST OF FIGURES Exhibit 10-1 Recommended Basic Recovery Widths (BRW, in feet from travel lane) .............................. 8 Exhibit 10-2 Horizontal Curve Adjustment Factors (Koc) ........................................................................... 8 Exhibit 10-3 Clear Zone Segments (Matching Selection to Attainable Clear Area)................................ 11 Exhibit 10-4 Sample Table of Clear Zone Widths (to be included in Project Plans) ............................... 13 Exhibit 10-5 Basic Point of Need Determination ..................................................................................... 25 Exhibit 10-6 Crush Accommodation for Parallel-Type Proprietary Terminals ........................................ 26 Exhibit 10-7 Runout Lengths ................................................................................................................... 28 Exhibit 10-8 Left Side Runout Lengths ................................................................................................... 29 Exhibit 10-9 Runout Length Alternatives ................................................................................................ 30 Exhibit 10-10 Backslope Anchorage for Weak Post Rail Systems .......................................................... 31 Exhibit 10-11 Back Slope Anchorage for Heavy-Post Blocked-Out Corrugated Rail .............................. 32 Exhibit 10-12 Clear Area Requirements for Gating Terminals................................................................. 33 Exhibit 10-13 Barrier Deflections for Standard1 Impacts .......................................................................... 36 Exhibit 10-14 Maximum Lateral Offset ..................................................................................................... 37 Exhibit 10-15 Deflection Reduction Factors ............................................................................................. 37 Exhibit 10-16 Intermediate Posts Required to Reduce Rail Deflection ................................................... 38 Exhibit 10-17 Minimum Shoulder Break Offsets (in feet) to Back of Guide Rail Posts ............................ 56 Exhibit 10-18 Guidance for Median Barrier Use on Non-Interstate High Speed (50 mph or greater) Freeways and Expressways ............................................................................................. 65 Exhibit 10-19 Recommended Barrier Locations for Uneven Medians ..................................................... 75 Exhibit 10-20 Single Slope Concrete Median Barrier .............................................................................. 76 Exhibit 10-21 Moveable Concrete Barrier ................................................................................................ 77 Exhibit 10-22 Truck Barrier (Extra High) .................................................................................................. 78 Exhibit 10-23 Terminals at Crossover Areas ........................................................................................... 84 Exhibit 10-24 Recommended Barrier Flare Rate Limits for Permanent Installations .............................. 87 Exhibit 10-25 Approved Sand Barrel Array for 90 km/h ......................................................................... 109 Exhibit 10-27 Location of HDM Guidance on Roadside Design Process for Existing Facilities ............ 136 Exhibit 10-28 Acceptable Barrier Heights When Upgrading Existing Facilities ..................................... 144 Exhibit 10-29 Example Page of Roadside Design Summary................................................................. 155 Exhibit 10-30 Recommended Guide Rail Installation Time Allowances ................................................ 170 EB 20-018 D.A. 05/01/2020 ROADSIDE DESIGN 10-5 10.1 INTRODUCTION The purpose of this chapter is to provide the designer with guidance on measures to reduce the number and/or severity of accidents when vehicles leave the traveled way. The concept of a forgiving roadside environment was developed in the 1960s. A key element of the concept was the creation of "clear zones" within which a driver might recover control
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