The National Academies

NCHRP 22-53 [Active]

Delineation of Linear Roadside Hardware Systems and Roadside Obstacles

  Project Data
Funds: $400,000
Staff Responsibility: Bijan Khaleghi
Research Agency: Texas A&M Transportation Institute
Principal Investigator: Nathan Schulz
Effective Date: 8/23/2022
Completion Date: 2/22/2025

BACKGROUND: Roadside safety hardware testing is conducted in a controlled environment that does not consider human factors and driver reaction to specific delineation practices of roadside hardware systems and roadside obstacles. Some state departments of transportation have reported that enhanced continuous delineation of roadside barriers have resulted in reduction of crashes. However, there are no widely-accepted guidelines on the application of delineation practices that would contribute to a reduction of crashes.


There is a need to identify and evaluate current practices and develop guidelines for delineating linear roadside hardware systems and roadside obstacles to enhance safety. Implementation of these guidelines will improve safety and reduce damage to property thereby benefiting transportation agencies and motorists.


OBJECTIVES: The objectives of this research are to (1) develop guidelines for delineating linear roadside hardware systems and roadside obstacles to enhance safety and (2) propose draft language to update relevant documents.

Accomplishment of the project objectives will require at least the following tasks.


PHASE I: (1) Collect and review domestic and foreign literature, research findings, and information relevant to the delineation of linear roadside hardware systems and other roadside obstacles (e.g., non-traversable slopes and multi-modal facilities adjacent to roadways) to enhance safety. This information may be obtained from published and unpublished reports, and contacts with public and private organizations. (2) Based on the review performed in Task 1, identify and evaluate practices for delineating linear roadside hardware systems and devices and other roadside obstacles. Based on this evaluation, identify new and existing practices recommended for further consideration/investigation in Phase II to help develop the anticipated guidelines. (3) Based on the work performed in Task 2, prepare an updated, detailed work plan to be executed in Phase II that includes an approach for (1) investigating the recommended practices; (2) developing rational guidelines for delineating linear roadside hardware systems and roadside obstacles; and (3) proposing draft language to update specific sections of the AASHTO Roadside Design Guide (RDG), the AASHTO Manual for Assessing Safety Hardware (MASH), and the AASHTO Policy on Geometric Design of Highways and Streets (Green Book) for consideration by AASHTO, and the FHWA Manual on Uniform Traffic Control Devices (MUTCD) for consideration by the Federal Highway Administration (FHWA). (4) Prepare an interim report that documents the research performed in Tasks 1 through 3. Following review of the interim report by the NCHRP, the research team will be required to make a presentation to the project panel. Work on Phase II of the project will not begin until the interim report is approved and the Phase II work plan is authorized by the NCHRP. The decision on proceeding with Phase II will be based on the contractor’s documented justification of the updated work plan.



PHASE II: (5) Execute the Phase II plan approved in Task 4. Based on the results of this work, (1) prepare the guidelines, (2) propose draft language to update specific sections of the RDG, the MASH, the Green Book, and the MUTCD, and (3) prepare an implementation plan. (6) Prepare a final deliverable that documents the entire research effort. Deliverable will include (1) a research report documenting the work performed in the project and used to develop the guidelines and propose updates to relevant documents, (2) the guidelines, (3) the proposed draft language for updating the relevant documents; and (4) an implementation plan. Each of these 4 items should be prepared as a standalone document. 


STATUS: Researchh in progress.

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