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TTI Research Supervisor: Akram Abu-Odeh, PhD. Research Scientist Texas A&M Transportation Institute Texas A&M University System TAMU 3135, College Station, Texas, 77843-3135 (979) 317-2628 |
Pooled Fund Technical Representative:
Mary F. McRae, P.E. Design and Construction Standards Engineer Alaska Department of Transportation & Public Facilities 3132 Channel Drive P.O. Box 112500 Juneau, AK 99811-2500 (907) 465-1222 |
Various constraints related to site-specific factors often limit the installation of existing American
Association of State Highway and Transportation Officials’ (AASHTO’s) Manual for Assessing
Safety Hardware (MASH) compliant transition rail and end treatment systems at bridge railing
ends. These constraints are common in locations with low speed, low volume traffic, and/or with
sidewalks. Therefore, practitioners must evaluate whether to leave such sites without any
protection or install a product in an untested configuration. This research project addresses this
gap in safety provision for sites under such constrained conditions.
The primary objective of this project is twofold. First, it seeks to develop comprehensive
guidance to assist practitioners in making decisions regarding the adequacy of a “do nothing”
approach in these constrained sites. Second, the project endeavors to conceptualize, design, and
simulate a short, straightforward, non-proprietary end treatment or attenuator that can be directly
connected to the bridge rail end. By providing a concise, uncomplicated attenuator, the project
provides a viable safety solution for locations where the installation of a MASH compliant
attenuator is not feasible, thereby enhancing safety outcomes in these specific sites.
The first objective of this project is focused on the development of decision tree or similar
procedure to assist practitioners in determining whether a “do nothing” approach is sufficient for
bridge rail end.
The second objective is to model and simulate a short, non-proprietary end treatment that can
directly connects to the bridge rail end.
This project will provide the enhanced safety of the roadway features by introducing a solution
for bridge end attenuation, addressing various site-specific constraints. The development of a
simplified and effective attenuator not only improves safety measures at these sites but also
assists State Departments of Transportation (DOTs) in optimizing their resources based on
analyses.
The TTI research team will provide a final report that will include a decision tree or similar
procedure to assist practitioners in determining whether a “do nothing” approach is sufficient for
bridge rail end.
The TTI research team will provide the engineering drawings sheets for the simple attenuator
design.
The work plan for this research includes five (5) tasks as described below:
Task 1: Literature Review
In Task 1, TTI research team will conduct a comprehensive literature review, examining relevant
reports and documents from key organizations and agencies, including the Roadside Design
Guide (RDG), the National Highway Traffic Safety Administration (NHTSA), the National
Cooperative Highway Research Program (NCHRP), and Department of Transportation (DOT)
standard plans, among others. The review will provide essential insight into current road safety
and design standards, serving as the baseline of this research.
Task 2: Factor Identification and Categorization
In this task, TTI research team will conduct outreach, possibly through a survey, to identify and
categorize critical factors influencing high-priority situations in a bridge end treatment, such as
layout, geometry, ADT, exposure levels, or other pertinent features.
Task 3: Analysis with Analytical Tools
In Task 3, TTI research team will utilize analytical tools, including the Roadside Safety Analysis
Program (RSAP) to identify the key factors that would trigger the need for some level of
attenuation. This will assist in pinpointing critical elements that demand specific attention for
bridge end attenuation solutions.
Task 4: Attenuator Model and Simulation (non-linear analysis)
Develop a simple, non-proprietary bridge end attenuator for at least some targeted situations.
In Task 4, TTI research team will create a simple, non-proprietary bridge end attenuator designed
for specific targeted situations, utilizing non-linear analysis and simulation techniques. The
objective is to develop an effective solution for bridge end attenuation in circumstances where
standard MASH compliant devices are not suitable due to site-specific constraints.
Task 5: Deliverables
The TTI research team will provide a final report that will include a decision tree or similar
procedure to assist practitioners in determining whether a “do nothing” approach is sufficient for
bridge rail end.
The TTI research team will provide the engineering drawings sheets for the simple attenuator
design and a final report detailing the work executed under this project.