The National Academies

NCHRP 22-53 [Anticipated]

Development of Guidance for Enhanced Delineation of Barriers and other Roadside Safety Hardware, Slopes, and Hazards

  Project Data
Source: AASHTO Committee on Design, Technical Committee on Roadside Safety
Funds: $450,000
Staff Responsibility: Amir N. Hanna
Fiscal Year: 2022

This project has been tentatively selected and a project statement (request for proposals) is expected to be available on this website. The problem statement below will be the starting point for a panel of experts to develop the project statement.

Roadside safety hardware is crash tested to assess the crashworthiness of the device. The current crash test criteria are contained in the AASHTO Manual for Assessing Safety Hardware (MASH) and all transportation agencies are in the process of implementing MASH hardware on their highway systems. However, like all hardware assessment, MASH testing is conducted within the sterile, idealized environment of a laboratory test deck and does not encompass human factors regarding perceived danger and consequent driver behavior to specific delineation practices of safety barriers or other roadside hazards. Transportation agencies have encountered situations where enhanced continuous delineation of the face of existing roadside barriers seem to be playing a significant role in the reduction of crashes and injury severity. Examples of such situations could be related to the reduction of motorcycle impacts at strategic locations where a metal rub-rail was added to the guardrail system and painted yellow. Similar crash reductions were noticed when the yellow colored DR-46 motorcycle attenuator rub-rail was added to existing guardrail systems. 

This research will develop guidance for enhanced delineation of roadside barriers and other hazards such as steep slopes in order to provide increased visibility and improved safety performance. Such guidance will also address delineation applications for reducing vehicle interaction with pedestrians and bikes on multi-modal roadways. 

The objectives of this research are to (1) identify best practices of enhanced delineation of roadside barriers and steep slopes, as currently adopted by transportation agencies; (2) identify the effectiveness of such delineating practices, as reported by existing transportation agencies data/studies; (3) develop guidance that agencies can apply to delineate roadside hardware systems, slopes, and multi-modal facilities adjacent to roadways; and (4) propose any needed updates of appropriate sections of the AASHTO Roadside Design Guide (RDG) and the Manual on Uniform Traffic Control Devices Recommended (MUTCD), and the AASHTO MASH standards.


Direction from the AASHTO Committee on Research & Innovation:  No crash testing is anticipated.


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