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.
Ford Safety Performance of Rechargeable Energy Storage Systems
This study of rechargeable energy storage systems (RESS) in electrified vehicles defines lithium ion battery performance-based safety metrics, safety performance test procedures, and metrics conducted at the vehicle level. Research involved identification, review, and assessment of existing test procedures to determine adequacy and applicability to this research. To define priority failure events in the RESS, a fault tree analysis (FTA) was conducted that lead to the identification of crush, overcharge and short circuits as principle fault mechanisms, and provided understanding of the key faults within those failure modes. The testing included data acquisition for voltage, current, and temperature supported with photographic and video files. The results are reproducible and repeatable test procedures indicating threshold levels that should not be exceeded in a vehicle fault event.
Front Seat Modeling in Rear Impact Crashes: Development of a Detailed Finite-Element Model for Seat Back Strength Requirements
NHTSA contracted EDAG, Inc., to re-examine feasibility of increasing the seat back strength by developing a detailed finite-element model of a current vehicle front seat design that can be used with existing biofidelic rear impact dummies to study seat performance in rear impact crashes. Results are the finite-element models of a 2014 Honda Accord mid-size sedan representing typical front seats. Two front seat models were developed using LS-DYNA simulation code, a manually operated seat and a power-operated seat, both capable of simulating occupant kinematics and injury performance measures in rear impact and capable of responding to incremental impulses spanning from 17 km/hr up to 40 km/hr.
Rear Amber Turn Signal Lamps Confirmation Test - Example Measurements
This report summarizes an evaluated draft test procedure for confirming amber rear turn signal lamp color. It adapts existing test procedures from FMVSS No. 108, Lamps, reflective devices, and associated equipment, to accommodate testing the lamps as installed on the vehicle. Four vehicles were tested. Overall, the test procedure was found to be easy to carry out and effective in determining turn signal lamp color.
Traffic Jam Assist Test Development Considerations
This report summarizes three preliminary Traffic Jam Assist (TJA) test scenarios, discusses test results of three commercially available vehicles equipped with TJA, assesses real-world scenarios, and considers performance capabilities of the TJA systems presently available. The first scenario involved a lead vehicle accelerating to the desired speed and braking to a stop. In the second scenario, a lead vehicle abruptly changed lanes to suddenly reveal a stopped vehicle. The final scenario used a cut-in and deceleration maneuver performed at close range to the subject vehicle. The three vehicles tested were a 2017 Mercedes E300, a 2017 Tesla Model S 90D, and a 2017 BMW 540i xDrive.
Pedestrian Protection – Assessment of the U.S. Vehicle Fleet
This study evaluated pedestrian protection in the U.S. vehicle fleet using established Euro NCAP pedestrian test procedures including lower legform and upper legform impacts to the front end of the vehicle and headform impacts to the hood and windshield. In general, global vehicles (models that include a U.S. variant and a European variant of the same vehicle) offer more pedestrian safety than vehicles marketed primarily in the U.S. The second objective assessed equivalency of pedestrian protection in U.S. versus European variants of the same vehicle model. U.S. variants performed worse than European variants in the lower legform assessment, but no worse than (and perhaps slightly better than) non-global “passenger cars.” In upper legform tests, the global “passenger cars” perform very well, with U.S. and European variants performing equally as well.
Evaluation of the Large Omni-Directional Child Anthropomorphic Test Device
In 2016 a new pediatric anthropomorphic test device (ATD) – the large omni-directional child (LODC) was developed. The LODC is designed to have anthropometry representative of a seated 9- to 11-year-old child and a flexible thoracic spine, instrumented abdomen, and realistic pelvis geometry to address the biofidelity and injury risk measurement limitations with the Hybrid III 10-year-old ATD (HIII-10C). This study presents an evaluation of the latest versions of the LODC (Rev4 and Rev5) that have increased biofidelity and durability and are more user-friendly. In addition to assessing biofidelity, durability, and repeatability of the LODC, reproducibility was also evaluated for the first time using multiple LODC ATDs.
Small Female/Older Occupant Thoracic Biofidelity Corridor Development
The objective of this study was to develop biofidelity corridors for the small female thorax. Small female specimens were tested in a frontal crash configuration using a simplified sled buck. The resulting biofidelity corridors are being used to evaluate the THOR 5th small female ATD. The THOR 5th ATD was tested in the same condition as the post mortem human surrogates.
Revised THOR 50th Percentile Male Dummy Seating Procedure
NHTSA developed a seating procedure for the THOR 50th percentile male dummy (THOR-50M). The original was released with a December 2015 Request for Comments (RFC), and some updates were presented at a public meeting at VRTC in August 2016. This report discusses the changes to the seating procedure since the original that were reflected updates to the THOR-50M, additional experience using the procedure, and comments received. Some revisions were minor wording changes to better clarify the steps of the procedure. The more significant revisions to the procedure are discussed in this report and include heel point definitions for different accelerator pedal types, seat fore/aft position, H-point tolerances, and final head angle.
Indicators of Driver Adaption to Forward Collision Warnings: A Naturalistic Driving Evaluation
Studies have found that vehicles equipped with forward collision warning (FCW) systems can help drivers reduce the likelihood crashes, but to date the research has only addressed initial safety benefits on short-term exposure (up to one month), and not how those benefits may change over time with longer exposure. This study looks at performance, safety impact, and driver acceptance of FCW systems with automatic emergency braking (AEB) over time using a one-year naturalistic field test of 38 participants (20 to 29 years old) driving 2013 Cadillac SRXs equipped with FCW and AEB systems. To assess safety, two areas were addressed: overall driving behavior and rear-end near crash events. Overall, the accuracy and frequency of FCW alerts in the field test were very high, while the accuracy and frequency of AEB events was not. No changed were observed in driver’s speed maintenance, following headway, or alert rate. Driver’s exposure to near-crash events showed a significant decrease in near-crash events per mile from a predicted 2.634 near-crashes per 1,000 vehicle miles traveled (VMT) during the first 1,000 miles to 0.615 conflicts per 1,000 VMT during the last 18,000 miles (a 76.6 percent decrease). Drivers showed a significant decrease in the number of near-crash events per month, from a predicted rate of 2.377 conflicts during the first month to 0.815 conflicts during the fourteenth month (a 65.7 percent decrease). These results suggest that the safety benefits of FCW systems are sustained over longer-term exposure.
Safety Performance of Rechargeable Energy Storage Systems
This report describes objective test procedures based on failure mode and effects analysis (FMEA) for meaningful, comparable, and quantitative evaluations of Li-ion-based rechargeable energy storage systems (RESSs) in electrically propelled platforms. These are applicable to all components of RESS and ancillary vehicle systems associated with electric propulsion; they can also serve as best practice guides for safety assessment of future designs. RESS safety performance is assessed with single and dual-point failure modes during all normal and abnormal operating conditions including charging, vehicle storage, operation, crash event, and post-crash state.