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.
Battery State of Health and Stability Diagnostic Tool Set Development
Traditional monitoring of electrochemical cells and batteries has been limited to voltage and temperature, but there are limits to how predictive voltage and temperature can be prior to thermal runaway events, which are often lagging indicators of battery failure. This work examines rapid electrochemical impedance spectroscopy (EIS) as a tool to determine cell or battery stability; to provide deeper understanding of how abused cells and batteries fail; and the technical basis of a tool that could be used to interrogate and even monitor cells for early signs of damage or failure. Idaho National Laboratories has developed a fast-impedance tool that uses off-the-shelf parts. This work evaluated that rapid impedance tool, including replicating the work performed with the traditional tool as well as collecting impedance data during dynamic conditions.
Biomechanical Response Manual: THOR 5th Percentile Female NHTSA Advanced Frontal Dummy, Revision 2
The THOR-05F (Test device for Human Occupant Restraint fifth percentile female) anthropomorphic crash test dummy is being designed to provide improved biofidelity compared to the Hybrid III Fifth Female, particularly in evaluating head and neck injuries due to air bag deployment and interaction with restraints (e.g., abdominal response in submarining) along with an improved pelvis, knee-thigh-hip, and lower leg. This manual describes the anthropometry and biomechanical response targets recommended to assess the THOR-05F. The tests and procedures described here were derived primarily for use by dummy manufacturers during the pre-production design and development process. They are designed to produce results in the form of time-history signals so objective quantitative scoring can be performed.
In-Vehicle Voice Control Interface Evaluation: Preliminary Driver Workload and Risk Analysis
This project evaluated distraction and relative risk associated with using voice control systems (VCS) while driving. It explores potential empirical measures and uses a modeling approach for evaluating risk with these voice-based systems via three studies: Study 1 and Study 2 assess potential measures of the workload and demands on the driver imposed by voice-based and hybrid (audio plus visual) tasks. Participants interacted with a “Wizard of Oz” VCS while driving and a novel radio tuning benchmark task was used. Study 2 included on-road data collection and data collection with a driving simulator. Risk estimates and crash severity estimates developed using this technique varied considerably by VCS task and by driver.
Development of Oblique Restraint Countermeasures
This study developed and demonstrated modified restraint systems for front seat occupants that can help provide reduced injury. The tests used the 50th percentile male Test device for Human Occupant Restraint (THOR) in both left and right oblique frontal crashes. Four baseline sled tests (driver near-side, driver far-side, passenger near-side, and passenger far-side) set up the baseline restraint performance. Then a set of baseline MAthematical DYnamic MOdels (MADYMO) were developed and validated against the baseline sled tests as well as Federal Motor Vehicle Safety Standards (FMVSS) No. 208 and the United States New Car Assessment Program (US-NCAP) frontal barrier tests. Nearly 100 sled tests and hundreds of MADYMO simulations systematically selected and tuned proposed restraint designs in four oblique crash conditions. Two modified restraint systems, a 3-point belt and relocated retractor, and a suspender 4-point belt, were used in the final sled tests. Results demonstrated that modified restraint systems can be tuned to help reduce the injury in oblique frontal crashes.
System-Level RESS Safety and Protection Test Procedure Development, Validation, and Assessment–Final Report
The technical report, “System Level RESS Safety and Protection Test Procedure Development, Validation, and Assessment” was prepared for NHTSA by Argonne National Laboratory via Interagency Agreement DTNH22-15-X-00513. The project originally initiated in August 2015 with a cost of $550,000. The draft report was received by NHTSA in December of 2017 and circulated for agency comments. These comments were assessed, and appropriate revisions were included in this final report.
A Test Track Comparison of the Global Vehicle Target and NHTSA’s Strikeable Surrogate Vehicle
This report compares forward collision warning alert and crash imminent braking intervention onset timing elicited by the Global Vehicle Target Revision E (GVT) to that observed during identical tests performed with NHTSA’s strikeable surrogate vehicle benchmark using three light vehicles and three rear-end crash scenarios were used for this evaluation. A secondary objective of this study was to describe some of the test-track-based use considerations related to the GVT, namely the dynamic stability and in-the-field reconstruction time after being struck by a test vehicle. GVT stability was assessed using straight line and curved path maneuvers at various speeds and lateral accelerations. Reconstruction times were examined using different impact speeds, directions of impact, and assembly crew sizes. Analyses suggest the Mercedes C300 and Volvo S90 responded similarly to both the GVT and SSV, with the Volvo S90 responses being the most consistent.
DC and AC Charging Safety Evaluation Procedure Development, Validation, and Assessment
Charging plug-in electric vehicles exposes new hazards and risks different from internal combustion engine vehicles. These must be defined and mitigated through proper design and verified via functional system performance testing. Unlike AC charging, where on-board charger and battery are controlled by the vehicle, DC charging uses an external charger and requires the vehicle, high-voltage system controls, and battery management systems to interact with an external device directly connected to the vehicle’s high-voltage battery. This report focuses on system-level safety procedures to test if a vehicle/charging system can safely handle failure modes and hazards associated with charging. This project developed a DC fast-charging safety test procedure, a holistic collection of tests based on 24 FMEAs conducted by the battery system developer for real-world applications and clients reflecting a broad range of in-field scenarios. This report presents validation and refinement of the test procedures used by SAE and addresses a range of vehicle charging technologies to include AC charging technology presently available for electric vehicles. This report documents these efforts to independently evaluate, refine, and validate test procedures that can be applied to vehicles, charger technologies, and battery configurations.
Statistics of Light-Vehicle Pre-Crash Scenarios Based on 2011–2015 National Crash Data
This report defines a new set of 36 distinct pre-crash scenarios that represent the crash population of light-vehicles (LVs) based on data from the 2011-2015 Fatality Analysis Reporting System (FARS) and National Automotive Sampling System General Estimates System (GES) crash databases. LVs include all passenger cars, vans, minivans, sport utility vehicles, and light pickup trucks with gross vehicle weight ratings less than or equal to 10,000 pounds. Pre-crash scenarios describe vehicle movements and the critical event that made the crash imminent (i.e., something occurred that made the collision possible). The 36 pre-crash scenarios are arranged into nine groups: control loss, road departure, animal, pedestrian, pedalcyclist, lane change, opposite direction, rear-end, and crossing paths. These nine groups account for 24,534 (94%) fatal crashes and an estimated 5,020,000 (89%) of all police-reported crashes based on the yearly average of the 2011-2015 FARS and GES crash databases, respectively. This report also provides crash characteristics for each pre-crash scenario and group in terms of environmental conditions, road geometry, crash location, vehicle/crash-related factors, driver characteristics, attempted avoidance maneuver, traffic violations, and crash contributing factors.
Technical Evaluation Of the TRL Pedestrian Upper Legform
The upper legform impactor was introduced by Transport Research Laboratory (TRL) to address injuries to the upper leg, pelvis, and hip of a pedestrian when struck by a vehicle. It is new to NHTSA and was evaluated at its Vehicle Research and Test Center. There are two objectives of this study. Since the foam in the TRL upper legform impactor has a history of sensitivity to humidity, the first evaluates the impactor under different humidity conditions. Vehicle tests were also carried out to see if the upper legform sensitivity to humidity carries over to vehicle tests. The second objective evaluated sensitivity to vehicle bumper design, repeatability, reproducibility, durability, and biofidelity.
DC Charging Safety Evaluation Procedure Development, Validation, and Assessment; and Preliminary Draft AC Charging Evaluation Procedure
This report describes and validates a holistic collection of test procedures assessing safety hazards to electric vehicles while being charged. If not properly protected and controlled, vehicle charging using either AC or DC current can introduce hazards ranging from high-voltage exposure to the vehicle or damage to the battery. The tests procedures in this report have been independently developed using commonly accepted single-point failure modes and hazards identified in 24 separate FMEAs related to electric vehicle applications of Li-ion battery technology and the system’s ability to effectively detect and mitigate safety-relevant occurrences during charging.