Feasibility Study for Addressing Extreme Site Constraints at Bridge Ends (602941)

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Final Report Link: Feasibility Study for Addressing Extreme Site Constraints at Bridge Ends

TTI Research Supervisor: 

Dusty R. Arrington

Associate Transportation Researcher

Texas Transportation Institute Texas A&M University System

3135 TAMU

College Station, Texas 77843-3135

(979) 845-4368

[email protected]


Pooled Fund Technical Representative:

Chris Guidry, P.E.

Assistant Bridge Design Administrator

Louisiana Department of Transportation Bridge Design

P.O. Box 94245

1201 Capitol Access Road Baton Rouge, LA 70802

(225) 379-1328

[email protected]


The scope of this research study was to investigate extreme site constraints at bridge ends encountered by State DOTs. A categorization methodology is provided for determining proper impact conditions and evaluation criteria for future design concepts. The researchers supplied impact conditions and evaluation criteria for future hardware designs for roadside safety application to be applied at extreme sites at bridge ends. This project does not aim to develop a hardware solution for these site conditions. This study aimed to develop criteria for the development of future hardware solutions. The test matrix presented as a solution will be based on data collected from previous research efforts. The resulting proposed criteria allows for the development of future products that are both crashworthy and that fit within the site-specific conditions. The research also involved developing a survey to identify critical case scenarios that could be further investigated. The survey aimed to collect data from all the State DOTs to help identify the most common critical case scenarios observed in different states. A comparison between the evaluation criteria in American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) and Federal Motor Vehicle Safety Standards (FMVSS) was discussed. This evaluation is to be utilized when site specific conditions make MASH compliance impossible.  The study identifies the cases where use of MASH is impossible and instead applies evaluation criteria in alignment with FMVSS. After analyzing specific extreme site constraint cases indicated by state DOTs, researchers developed criteria for evaluating roadside safety devices placed in areas with extreme site constraints.

Updated June 4, 2024