BACKGROUND

According to the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) crash tests, devices sometimes fail due to relatively insignificant damage to the vehicle, as MASH does not allow for any part of the device or vehicle component to enter the vehicle compartment. If there is any penetration, the device fails that test. Some deformation of the vehicle occupant compartment is allowed, but varies by area of the vehicle. Although engineering judgment and experience indicate that minor deformation/penetration does not normally pose a safety risk to occupants, MASH is very stringent in this area. 

As with many AASHTO publications, early editions often contain guidelines based on expert consensus rather than research, and as time goes on committees request research to address these areas. Without solid information on the risk posed to vehicle occupants from some minor types of crash test damage, the thresholds in AASHTO documents need to err on the side of caution (e.g., “no penetration into the occupant compartment”). As states, academia, and industry work to develop MASH hardware and fully implement MASH, some devices fail crash tests even though engineering judgement suggests that the devices appear to provide the desired protection to vehicle occupants. Research is needed to determine whether deformations and penetrations that appear to be relatively minor — but are currently cause for failed MASH crash tests — do in fact present a safety risk to vehicle occupants.

OBJECTIVES

The objectives of this research are to (1) evaluate the MASH limits for test vehicle deformations and penetrations by roadside safety features and vehicle components and (2) conduct tests to ensure the thresholds for test vehicle occupant compartment deformations and penetrations most appropriately represent potential safety risk to occupants in the current vehicle fleet.

Achieving these objectives would make MASH testing thresholds more realistic, which can lead to increased development and use of MASH devices.

STATUS: Work has been initiated. The first interim report is expected in August 2025.