The National Academies

NCHRP 22-32 [Pending]

Development of Methods to Evaluate Side Impacts for Next Edition MASH

  Project Data
Funds: $500,000
Contract Time: 40 months
Staff Responsibility: Mark S. Bush


Each year, roadway departure crashes in the United States result in serious injuries and fatalities. Between 2012-2014, the average number of fatalities per year resulting from roadway departure crashes was 18,355. (Source: Fatal Analysis Reporting System, NHTSA). Side impacts of vehicles into roadside hardware are a growing public safety problem. In particular, side impacts with guardrail account for 22 percent of fatalities in passenger vehicle-guardrail crashes (Source: Gabler and Gabauer, 2007). The occupant of a passenger vehicle that side impacts a guardrail has a 30 percent higher probability of being fatally injured than the occupant of a car involved in a frontal impact into a guardrail. Many roadside safety features (e.g., terminals, guardrail end treatments, crash cushions, and luminaire and sign supports) are designed to break away under the loads which are typical of a frontal impact. However, side impacts by non-tracking vehicles may not have enough force to engage the breakaway mechanisms of these features. Because the side of a vehicle, unlike the front, has less structure and crumple zone, side impacts can result in especially severe injuries. To date, however, no substantive improvements have been made to the performance of roadside safety features during vehicle side impacts. NCHRP Report 350 provided side impact test and evaluation procedures for informational purposes; however, there are no recommendations or requirements for side impact crash testing of roadside hardware. More recently, the NCHRP Report 350 appendix for side impact test and evaluation procedures was not included in the AASHTO Manual for Assessing Safety Hardware (MASH) crash test procedures. Little is known about how Report 350- or MASH- compliant hardware performs in side impact crashes. No research to date has developed a comprehensive approach for evaluating roadside hardware under side impact conditions. The development of methods for evaluating these crashes would lead to improvements in roadside safety hardware and improved safety of the motoring public. Results of this research will enable transportation agencies to set and evaluate its level of safety risk and use quantitative information in the decision-making process.


The objectives of this research are to develop recommended test procedures considering critical Test Level 3 vehicles to effectively measure vehicle side impacts, and validate/verify the test procedures. This research shall focus on terminals; however, additional roadside safety devices should also be identified and considered. A combination of vehicle simulation and testing, such as, but not limited to, full scale, or pendulum testing is envisioned as part of this research. The research results are intended for inclusion as a new chapter or supplement in a future edition of the Manual for Assessing Safety Hardware (MASH). The research results will also include recommendations for future edition enhancements of the Roadside Design Guide (RDG).


A kick-off teleconference of the research team and NCHRP shall be scheduled within 1 month of the contract’s execution. The work plan should be divided into two phases, with each task described in detail. Phase 1 will produce an interim report and consist of, at minimum, preliminary recommended test procedures considering critical Test Level 3 vehicles to effectively measure side impacts, and a validation verification plan which shall demonstrate/promote the improvement of roadside safety device performance. An outline or framework of text and the proposed test procedures for inclusion in the MASH, and validation and verification procedures completed, planned, or anticipated shall be identified. Any preliminary recommendations for further enhancements to MASH and RDG may be included. The interim report will describe the work completed in the Phase 1 tasks and provide an updated work plan for the Phase 2 tasks to complete the project objectives. The updated Phase 2 work plan should describe the manner in which the proposer intends to use the information developed in Phase 1 to satisfy the project objectives. The Phase 1 interim report and panel meeting should occur after the expenditure of no more than 40 percent of the project budget. Submission of the Phase 1 report will be followed by a face-to-face meeting with NCHRP and the project panel. No work shall be performed on Phase 2 without NCHRP approval.
At the completion of Phase 2, the final deliverables at a minimum shall include:

1. A final report documenting the entire project that also includes an executive summary and the research team’s recommendation for implementing or incorporating and evaluating side impact testing by both the public-private roadside safety community, and additional research need priorities including proposed budgets and time lines.
2. A stand-alone comprehensive compilation of materials, evaluation methodology, and guidance intended for incorporation in a format suitable as a supplement or new chapter for possible adoption in the next edition MASH, and recommendations for additions to the RDG.
3. An electronic or PowerPoint presentation describing the project background, objective, research method, findings, and guidelines that summarizes the project and that can be tailored for specific audiences.
4. A webinar on the results of the research and the deliverables.
5. A stand-alone technical memorandum titled “Implementation of Research Findings and Products”. Proposers may recommend additional deliverables to support the project objectives.

Research in progress.

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