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Development of Guidance for Non-Standard Roadside Hardware Installations

Description:

Roadside safety hardware such as guardrail is crash tested to assess the crashworthiness of the device. The current crash test criteria is contained in the AASHTO Manual for Assessing Safety Hardware (MASH) and all highway agencies are in the process of implementing MASH hardware on their systems. Like all hardware assessment however, MASH testing is conducted within the sterile, idealized environment of a laboratory test deck. In practice, conditions are seldom so ideal.

Agencies frequently encounter situations where the approved roadside safety hardware will not fit the location. Agencies may address these situations with special site-specific designs. Some possible examples of non-standard roadside applications could be:

• Modifying a crash tested barrier to fit a location (e.g. Install posts with less embedment than what was tested).

• Using a radius guardrail at an intersection where there is not enough room for a crash tested design.

• Using an older crash test standard (e.g. a MASH approved approach transition may not fit at a location so an NCHRP-350 transition is used).

• Determination to not provide shielding (e.g. delineate an object).

• Only shield some obstacles at a location (e.g. shield blunt edge of bridge, some of the steep slope but not all the steep slope).

This research will develop guidance for “non-standard roadside applications” where standard practices of crash tested barrier cannot be used.

Objective:

This research will develop guidance for “non-standard roadside applications” where standard practices of crash tested barrier cannot be used.

Benefits:

Roadside safety hardware is critical for reducing severe crashes on the nation’s highways. While approved crash tested hardware reduces the risk of severe crashes for the majority of applications, situations may be encountered where the approved roadside safety hardware does not fit the specific location. There is an urgent need to develop guidance for special site-specific designs to guide the highway Agencies on appropriate hardware use. Absence of standard hardware application is not an excuse to do nothing; some reasonably safe solution is better than nothing at all.

In the absence of this research, the frequency of severe injury and fatal crashes will likely escalate as more miles of roadway with no, or non-standards roadside hardware installations continue to increase.

Related Research:

Most published research is related to approve crash tested systems for existing (or past) roadside safety hardware testing and evaluation standards. Although highway Agencies often encounter situations where approved roadside safety hardware does not fit the existing location, there is no specific documentation of practices designed to mitigate these problems. Neither are guidelines available on how the Agencies should address these situations. Irrespective of this perceived lack of resources, a literature search should be conducted to identify to the extent possible, non-standard practices in the field.

Tasks:

The objective of this research is to:

  1. Identify common non-standard situations that are encountered by highway Agencies

  2. Investigate potential crash tested solutions for these situations, if practical

  3. Identify best practices for situations where a crash tested solution may not be practical

  4. Develop a general methodology that Agencies can apply to any non-standard situations

  5. Decrease to the extent possible, the tort liability placed on Agencies when they apply non-standard applications

Implementation:

The result of this research project will provide a guidance to assist state, local and tribal agencies to provide the most practical solution for non-standard roadside hardware installation conditions. The guidance could be further implemented through an update of appropriate sections of the AASHTO Roadside Design Guide (RDG). Recommended guidance or specific solutions could be incorporated into a future update of MASH with proper review and consideration by AASHTO Technical Committee on Roadside Safety (TCRS).

Results of this research and the resulting guidance will be disseminated to state DOT design engineers, consultants, and practitioners through presentations and webinars at appropriate industry and professional meetings including TRB Roadside Safety Design Committee, AASHTO TCRS, and Committee on Bridges and Structures Technical Committee T-7 “Guardrails and Bridge Rails.”

Relevance:

Results of this research and the resulting guidance will be disseminated to state DOT design engineers, consultants, and practitioners through presentations and webinars at appropriate industry and professional meetings including TRB Roadside Safety Design Committee, AASHTO TCRS, and Committee on Bridges and Structures Technical Committee T-7 “Guardrails and Bridge Rails.”

Sponsoring Committee:AFB20, Roadside Safety Design
Research Period:24 - 36 months
Research Priority:High
RNS Developer:Alex Price, Erik Emerson, Chiara Silvestri Dobrovolny, Joseph Jones, and Roger Bligh
Source Info:TRB AFB20 Mid-Year Meeting 2019, Reno NV
Date Posted:01/06/2020
Date Modified:01/06/2020
Index Terms:
 
Subjects    
Highways
Design
Safety and Human Factors

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