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Safety Risks of Occupant Compartment Damage During Crashes


Each year, there are significant numbers of road departure crashes that result in serious injuries and fatalities. Many of these crashes involve impact events with roadside safety hardware and features. Since the early 1960s, there has been an evolution of safety performance guidelines used to evaluate the crashworthiness of roadside features.

The American Association of State Highway and Transportation Officials (AASHTO) uses the Manual for Assessing Safety Hardware (MASH) to crash testing and evaluation of roadside features. Quantifying intrusion and deformation of the occupant compartment is part of deciding if a roadside feature is crashworthy. The evaluation criteria states that the test article should not show potential for penetrating the occupant compartment. It is believed that more clarity is required within MASH to address the potential of penetration.

Although test article penetration is partially addressed, the MASH 2016 impact safety criteria does not clearly address the potential risks when vehicle components penetrate the occupant compartment. In some crash test scenarios, vehicle components may penetrate further into the occupant compartment than that for components of test articles. Therefore, there exists a need to address whether vehicle component penetration into the occupant compartment should considered similarly to test article penetrations.

Currently, it is proper to re-examine the MASH limits for occupant compartment deformation and the risks associated with test article penetration. It may be necessary to decide if vehicle component penetration poses similar risks to occupants and propose limits for vehicle component penetration.

Ideally, an objective crash data from police reports would be used to develop deformation and penetration limits. There are concerns that crash reports lack details on penetrations and occupant compartment deformation.

In recent years, there has been an increase electric vehicles (EVs) in the United States. Limited real-world crash data has already showed potential fire risks for EV crashes. In the future, penetration and deformation criteria may be more critical.

In summary, this research study will focus on improvements and clarifications to the MASH guidelines as they pertain to deformations of and penetrations into the occupant compartment.


For this research study, several objectives are expected:

  1. Review and standardize the MASH language for deformation, intrusion, and penetration of test vehicles.

  2. Review and document historical research on deformation limits for the MASH impact safety guidelines/standards.

  3. Examine whether the existing deformation limits and areas of concern are suitable, and recommend changes to the deformation limits, as needed. Clarify or develop protocols for handling boundaries between regions with varied deformation limits.

  4. Review the types, locations, and extents of occupant compartment penetrations, and the potential for penetration, by roadside safety features into passenger vehicles and heavy trucks.

  5. Propose methods for investigating and deciding motorist risks from occupant compartment penetrations, such as through biomedical analysis, computer simulation, component testing, full-scale crash testing, review of crash tests, real-world crash data, etc.

  6. Investigate and classify the risks associated with roadside safety feature penetrations into the occupant compartment of passenger vehicles and heavy trucks.

  7. Investigate and classify the risks associated with vehicle component penetrations into the occupant compartment of passenger vehicles and heavy trucks.

  8. Considering motorist risks, decide efficacy of existing MASH penetration guidance. Determine potential changes to MASH penetration guidance. Compare and discuss the motorist risks associated with existing and suggested vehicle penetration guidance and the associated safety benefits.

  9. As needed, develop recommendations for consideration to update the deformation limits and penetration guidelines in MASH.

  10. As needed, prepare a list of future research needs identified in this project and note the estimated funding needs, anticipated tasks, and program periods.


There is a need to review and clarify existing penetration and occupant deformation criteria. There may be some low-risk penetrations that may be acceptable (e.g. a bolt head that has penetrated a windshield with little risk of injuring vehicle occupants). MASH needs to address vehicle component penetration into the cab and the risk of occupant injury. MASH may need to consider risks to EV and crashes into roadside hardware.

Related Research:

Below is a sampling of crash tests where there has been penetration by test article, penetration by vehicle components, or excessive occupant compartment crush.

Sample Literature:

Faller, R., Rosenbaugh, S., Bielenberg, R., Lechtenberg, K., Holloway, J., Stolle, C., Schmidt, J., Reid, J., and Pajouh, M., Investigation and Mitigation of Post Penetration into Floor Pan of 1100C Small Cars, Transportation Research Board, Transportation Research e-Circular No. E-C220, First International Roadside Safety Conference, San Francisco, California, June 2017. [Numerous post penetrations through the floor pan areas of small passenger vehicles were encountered during the development of cable barrier systems.]

Bielenberg, R.W., Asselin, N.M., and Faller, R.K., MASH TL-3 Evaluation of Concrete and Asphalt Pin Tied-Down Anchorage for Portable Concrete Barrier, MwRSF Research Report No. TRP-03-386-19, Performed for the Wisconsin Department of Transportation, Performed by Midwest Roadside Safety Facility, University of Nebraska-Lincoln, April 12, 2019. [Left-front wheel pushed open left-side lower side panel and floor pan/toe pan, resulting in rim penetration into occupant compartment.]

Polivka, K.A., Faller, R.K., Sicking, D.L., Rohde, J.R., Bielenberg, B.W., Reid, J.D., and Coon, B.A., Performance Evaluation of the Free-Standing temporary Barrier – Update to NCHRP 350 Test No. 3-11 (2214TB-1), MwRSF Research-Report No. TRP-03-173-06, Performed for the National Cooperative Highway Research Program (NCHRP), Performed by Midwest Roadside Safety Facility, University of Nebraska-Lincoln, October 11, 2006. [Left-front wheel was dislodged, became pinched between concrete barrier and vehicle, then contacted and shattered left-side driver’s window.]

Rasmussen, J., Faller, R., Lechtenberg, K., Sicking, D., and Holloway, J., Safety Investigation and Guidance for Work-Zone Devices in Freight Transportation Systems Subjected to Passenger Car and Truck Impacts with New Crash Standards, MwRSF Research Report No. TRP-03-225-10, MATC-UNL Report No. 100, Performed for the Mid-America Transportation Center and the Smart Work-Zone Deployment Initiative, Performed by the Midwest Roadside Safety Facility, University of Nebraska-Lincoln, March 1, 2010. [Components of 350-approved WZTCDs penetrated passenger vehicles under MASH TL-3 testing.]


(See objective section)


Results from this research study will be forwarded to the AASHTO Technical Committee for Roadside Safety (TCRS) for consideration in a future update to the MASH safety performance guidelines. There exists a high potential for these research findings to be implemented and result in the use of improved and more effective roadside safety feature across U.S. highways and roadways.


Results from this research study will be forwarded to the AASHTO Technical Committee for Roadside Safety (TCRS) for consideration in a future update to the MASH safety performance guidelines.

Sponsoring Committee:AKD20, Roadside Safety Design
Research Period:24 - 36 months
Research Priority:High
RNS Developer:Ronald K. Faller, Erik Emerson, Kristen Schuster, Bill Wilson, and Robert Bielenberg
Source Info:2021 AKD20 Summer Meeting (Virtual)
Date Posted:01/09/2022
Date Modified:01/31/2022
Index Terms:Vehicle design, Vehicle safety, Vehicle occupants, Ran off road crashes, Roadside hazards, Crashworthiness, AASHTO Manual for Assessing Safety Hardware, Deformation, Vehicle compartments,
Cosponsoring Committees: 
Safety and Human Factors
Vehicles and Equipment

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