An Exploration into Variations in Guardrail Approach Transitions to Rigid Barrier (615991)

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Problem Statement

In the field, some approach transitions have deficiencies that should be addressed.   The difficulties are that there are many different transition designs and many different deficiencies in field installation.  This makes it difficult to determine how to address deficiencies.  This research project will use computer modeling to analyze and prioritize installation deficiencies in approach transitions.


This research intends to use computer modeling to identify, when certain field variations in approach transition to a rigid barrier, may be problematic.


This project will benefit the members of the Roadside Safety Pooled Fund by providing deThis project will benefit the members of the Roadside Safety Pooled Fund by providing crashworthiness assessment for certain field variations of approach transition to a rigid barrier. This study will be a valuable resource on possible common field variations that the members of the Roadside Safety Pooled Fund can implement when needed.


The TTI research team will prepare and submit a research report fully documenting all of the work completed within this project. Application documentation for an FHWA Eligibility Letter will be provided if applicable.  If not, the research team will provide engineering justification explaining that the critical tests were performed.

Work Plan

Task 1:  Conducting a Preliminary Literature Review and State Survey

The TTI research team will perform a preliminary literature review of approach transitions to a rigid barrier that has been investigated and/or tested per MASH conditions in the past.  To complete this investigation, it is anticipated that the researchers will poll the Department of Transportation (DOT) Members.  Results of the conducted survey will allow the TTI research team to identify common design variations of approach transitions to be considered for evaluation in future tasks.

Task 2:  In-Depth Reviewing of Previous Studies and Identifying/Prioritizing the Possible Variations Based on the State Survey

Based on the results from Task 1 and the previous studies, the TTI research team will determine common designs for approach transition and prioritize the possible field variations that need to be investigated by computer simulation.

Task 3:  Performing Computer Simulation

The researchers will perform computer simulations to evaluate MASH crashworthiness of the high prioritized system variations. Some variation examples that may be investigated through computer simulation are listed below.  

The number of problems to be investigated will be limited to the total budget.

Task 4:  Report, Recommendations, Report, Recommendations, and Guidelines

The TTI research team will generate a final report of the findings from the research and testing study.  Results will be reported in terms of system performance, vehicle stability, and occupant risk factors and will be compared to MASH 2016 crashworthiness criteria.  The TTI research team will further provide recommendations for acceptable field variations of approach transitions to a rigid barrier.

TTI Research Supervisor:
Maysam Kiani, Ph.D., P.E.
Assistant Research Engineer
Texas A&M Transportation Institute
Texas A&M University System
TAMU 3135
College Station, Texas 77843-3135
(979) 317-2693
[email protected]
 Pooled Fund Technical Representative:
Erik Emerson, P.E.
Standards Development Engineer-Roadside Design
Wisconsin Department of Transportation
Bureau of Project Development
4802 Sheboygan Ave., Room 651
P.O. Box 7916
Madison, WI 53707-7916
(608) 266-2842
[email protected]


  1. Jowza, E., et al. (2012). Safety Investigation and Guidance for Retrofitting Existing Approach Guardrail Transitions, MwRSF.