Final Report: Recommended Guidelines for the Selection of Test Levels 2 through 5 Bridge Railings NCHRP 22-12(03) February 10, 2014 Limited Use Document This Final Report is furnished only for review by members of the NCHRP project panel and is regarded as fully privileged. Dissemination of information included herein must be approved by NCHRP. Malcolm H. Ray, P.E., Ph.D. Christine E. Carrigan, P.E., Ph.D. P.O. Box 312 12 Main Street Canton, Maine 04221 TABLE OF CONTENTS List of Tables ...................................................................................................................... v List of Figures ................................................................................................................... vii Introduction ......................................................................................................................... 1 Literature Review................................................................................................................ 3 Exemplar Crashes ........................................................................................................... 4 Crashes in the Media ................................................................................................... 4 Crashes Investigated by the National Transportation Safety Board ......................... 23 Crash Testing ................................................................................................................ 31 NCHRP Report 230 .................................................................................................. 33 1989 AASHTO Guide Specification for Bridge Railings ........................................ 33 NCHRP Report 350 .................................................................................................. 35 Manual for Assessing Safety Hardware (MASH) .................................................... 36 High Containment Barriers ....................................................................................... 37 Guidelines and Specifications ....................................................................................... 41 FHWA and AASHTO ............................................................................................... 41 The States .................................................................................................................. 49 International Specifications ...................................................................................... 58 Summary ................................................................................................................... 67 Crash Data Studies ........................................................................................................ 70 FHWA Narrow Bridge Study ................................................................................... 70 NCHRP 22-08 ........................................................................................................... 72 Kansas Bridge Rail Study ......................................................................................... 73 Analysis Methods for Bridge Railing Selection ........................................................... 74 BCAP ........................................................................................................................ 75 RSAP......................................................................................................................... 78 RRRAP ..................................................................................................................... 80 Risk Analysis ............................................................................................................ 81 Conclusions ................................................................................................................... 82 Results Of Survey Of Practice .......................................................................................... 85 Introduction ................................................................................................................... 85 Survey Questions .......................................................................................................... 85 Summary ....................................................................................................................... 95 Development of Bridge Rail Selection Guidelines ........................................................... 97 Crash Data ..................................................................................................................... 97 New Jersey Median Barrier ...................................................................................... 98 i Massachusetts Median Barrier .................................................................................. 99 Washington State Median Barrier ........................................................................... 101 Pennsylvania Bridge Railing................................................................................... 102 Ohio Bridge Railing ................................................................................................ 104 Nebraska Bridge Rails ............................................................................................ 107 After Penetration Hazards ....................................................................................... 109 Summary of Crash Data .......................................................................................... 110 Encroachment ............................................................................................................. 110 Encroachment models for roads over capacity ....................................................... 111 Low-Volume Encroachments ................................................................................. 112 Annual Traffic Growth ........................................................................................... 112 Traffic Mix Considerations ..................................................................................... 112 Truck Trajectories ................................................................................................... 116 Encroachment Adjustments for Site-Specific Characteristics ................................ 128 Crash ........................................................................................................................... 130 Predicted Penetration, Rollovers and Vaults .......................................................... 130 Severity ....................................................................................................................... 135 Bridge Railing Crash Severity ................................................................................ 136 Bridge Railing Penetration Severity ....................................................................... 137 Costs ............................................................................................................................ 139 Project Life.............................................................................................................. 140 Regional Cost Variations ........................................................................................ 140 Temporal Cost Variations ....................................................................................... 146 Bridge Railing Agency Costs.................................................................................. 149 Bridge Railing Crash Costs ..................................................................................... 150 Sight Distance Considerations .................................................................................... 154 Analysis Methods........................................................................................................ 157 Benefit-Cost versus Risk Approach ........................................................................ 158 Developing the Selection Guidelines ...................................................................... 159 Selection Guidelines ....................................................................................................... 167 Bridge Rail Risk Assessment Process ........................................................................ 167 Discussion ................................................................................................................... 176 Implementation ....................................................................................................... 176 Critical Values for Design ...................................................................................... 177 Test Levels Considerations ..................................................................................... 178 ii The Risk Line .......................................................................................................... 179 Recommended Selection Guidelines Verification ...................................................... 181 Comparisons to the 1989 AASHTO Guide Specification and NCHRP 22-08 ....... 181 Example Bridge Railing In Service ........................................................................ 182 CONCLUSIONS............................................................................................................. 191 APPENDIX A: Alternative Graphs for Figure 52 ......................................................... 193 APPENDIX B: Bridge Rail Selection Guidelines ........................................................