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Vehicle Safety

Resources

The Office of Vehicle Safety Research and supports U.S. DOT’s and NHTSA’s safety goals by conducting research and safety testing of motor vehicles and motor vehicle equipment. 

NHTSA’s recently published vehicle safety reports are listed chronologically below.



133 Results
Title
 

Hydrogen Container Performance Testing

This report describes research to evaluate the life cycle durability testing requirements for high pressure hydrogen containers set forth in the Global Technical Regulation (GTR) No. 13 for hydrogen and fuel cell vehicles. NHTSA is considering adopting the GTR requirements into a Federal Motor Vehicle Safety Standard.  However, the GTR lacks detail and contains inconsistencies that can only be resolved through development and evaluation of laboratory test procedures. NHTSA contracted Powertech Labs, which is equipped to conduct the specialized hydrogen container assembly testing required in the GTR, to develop detailed test procedures and generate test data to confirm the feasibility of conducting the proposed test sequences. These tests consist of a series of hydraulic and pneumatic pressure cycling and flaw tolerance tests meant to simulate a 15-year service life.  Hydrogen containers from three manufacturers were subjected to the tests.  Setup diagrams, equipment, procedures, instrumentation, results, and observations were documented.

Firewall Design in Buses to Mitigate the Propagation of Engine Fires

This report evaluates designs of the partition (firewall) between the engine compartment and the passenger compartment in current motorcoaches, medium-size buses, and school buses. Research examined the ability of the firewalls to mitigate the propagation of fire originating in the engine compartment into the passenger compartment, the effect of openings or gaps in firewall designs on ability to mitigate fire propagation, of the firewall under a frontal impact crash for front-engine compartments or rear impact for buses with rear engines, improvements to firewall designs for mitigating propagation of engine fires into the passenger compartment, and practical considerations and design constraints for improved firewalls to mitigate propagation of engine compartment fires into the passenger compartment.

Foundations of Automotive Software

This report chronicles the history as well as the current state-of-the-art practices of software development within the automotive sector.  Key concepts, approaches, trends, and knowledge of automotive software development were collected to benchmark industry practices as well as to compare these to non-automotive industry sectors.  The report provides a conceptual framework and taxonomy to articulate the relationships among relevant factors driving the evolution of automotive software development, which can be updated to incorporate new classifications and/or sub-classifications as the automotive software development landscape evolves.

Testing of Unattended Child Reminder Systems

NHTSA tested aftermarket, prototype, and original equipment manufacturer (OEM) unattended child reminder systems available for purchase or testing in the summer of 2020.  Generalized functional assessment methodologies to document the systems’ capabilities were developed.  The study assessed nine new systems and technologies introduced since the previous study was conducted in 2015. Results showed that each system met own design criteria, alerting the caregivers when vehicles were turned off with children still inside. OEM systems met criteria and alerted the caregivers with a display or audio alert as designed. However, the rear-door logic systems as currently implemented will not ensure that all occupants are out of the vehicle at the end of the trip. The systems performed differently in addressing some real-world situations encountered in the Special Crash Investigations case reviews of pediatric vehicular heatstroke fatalities in 2019.

Propagation Mitigation Testing Procedures, Modeling, and Analysis

This report explores propagation mitigation in packs of lithium ion pouch cells commonly used in large electric vehicles. Abuse tests were then used to initiate failure within a single cell in either the sub-assembly or pack. It developed a numerical model to capture damage propagation in lithium ion cells and modules in which thermal runaway is triggered using different initiation methods. The interplay of three parameters for passive thermal management on thermal runaway mitigation was numerically studied, including thermal mass of metallic inserts, thermal contact resistance between components, and cooling rate. Based on these results, it found that connecting metallic inserts between cells instead of using separate metallic inserts between cells is more helpful for thermal runaway mitigation since the former can take advantage of total thermal mass of metallic inserts, while the latter only of the thermal mass of individual metallic inserts next to the damaged cell.

Event Data Recorder Duration Study Appendix to a Report to Congress

The EDR duration study was initiated in August 2016 and conducted by researchers at Virginia Tech over a 9-month period.  The research examined existing NHTSA crash investigation programs and naturalistic driving studies to provide bounds on the recording durations necessary to capture available driver inputs preceding a crash. This is the appendix for the report: Results of Event Data Recorders Pre-Crash Duration Study: A Report to Congress.

Results of Event Data Recorders Pre-Crash Duration Study: A Report to Congress

The EDR duration study was initiated in August 2016 and conducted by researchers at Virginia Tech over a 9-month period.  The research examined existing NHTSA crash investigation programs and naturalistic driving studies to provide bounds on the recording durations necessary to capture available driver inputs preceding a crash. This report provides the detailed results from that effort. It is accompanied by its appendix: Event Data Recorder Duration Study Appendix to a Report to Congress.

Comparison of the aPLI, FlexPLI With Upper Body Mass, and FlexPLI Pedestrian Legforms in Matched-Pair Vehicle Tests

Pedestrian knee ligament injuries and lower leg fractures are the most frequent and among the most debilitating long-term injuries in motor vehicle crashes. Global Technical Regulation No. 9, Pedestrian Safety, has been adopted by the international community to mitigate these pedestrian injuries through improved vehicle bumper systems. The current UN GTR includes the flexible pedestrian legform impactor (FlexPLI), which simulates the lower limb of a pedestrian and is the device widely used in global New Car Assessment Programs to assess the protection level of the front-end structures of vehicles. This study evaluated the upper body part addition to the FlexPLI (FlexPLI-UBM) and the advanced pedestrian legform impactor (aPLI) and compare vehicle test results with one another and with the current FlexPLI in matched impacts.

WorldSID 50th Percentile Male Durability Assessment

This report documents the durability assessment of the WorldSID 50th percentile male dummy when exposed to severe test conditions. The dummy was subjected to component qualification tests conducted at elevated energy levels. Before and after completion of the elevated energy tests, the dummy was exposed to baseline energy levels to help assess possible changes in the dummy’s responses due to the elevated energy tests. Components of the dummy were also closely inspected after each test to determine if any damage occurred. This assessment demonstrated the dummy exhibits good durability.

Enhanced Seat Belt Reminder Systems: An Observational Study Examining the Relationship With Seat Belt Use

Reducing motor vehicle crashes and injuries remain a priority for the highway safety community. Over 90 percent of drivers and front passengers use seat belts but about half of crash-related fatally injured occupants were unbelted. Motor vehicle manufacturers install seat belt reminder systems in compliance with FMVSS No. 208. The systems vary in audible sounds, instrument panel icons, text messages, intensity, and duration. Some exceed FMVSS No. 208 requirements and are recognized as enhanced seat belt reminder (ESBR) systems. This project examined effectiveness of various ESBR systems in promoting seat belt use among drivers and right-front seat passengers. Data collectors observed drivers and right-front seat passengers in 69,984 vehicles in 8 States and recorded age, gender, and belt use, vehicle type, and license plate number. State DMVs were able to provide data on 61,074 vehicles. Results showed a beneficial effect of combinations of sound, icon, and text elements; of extended periods of warning systems; and of systems compliant with European New Car Assessment Programme standards. The effectiveness of the presence and magnitude of specific ESBR systems are dependent upon whether the State has a primary seat belt use law.