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.
Human Factors for Connected Vehicles Transit Bus Research
This report describes the tasks and demands associated with driving a transit bus, and directly supports the development of design guidelines for future transit safety technologies. The frequency and costs of bus-pedestrian accidents have created considerable interest in technologies that detect pedestrian hazards and warn the bus operator in time to mitigate or prevent an accident. This project addressed a lack of data on bus operator task demands through a mix of surveys, literature reviews, ride-alongs, cognitive task analyses, prototyping activities, and focus groups. The project team was aided tremendously by the support and involvement of transit agencies and their drivers in Seattle, Washington, and Portland, Oregon (King County Metro & TriMet). Key findings from the task analyses illustrated the high demand and complicated nature of bus operator specific activities such as the management of passenger boarding/payment, the navigation of intersections, and the driving on roadways where there is the co-occurrence of visual demands in disparate portions of the roadway scene and bus interior. The project also identified: safety issues (e.g., the impact of current riders on hazard detection, possible conflict between drivers’ behaviors and local laws/policy, and impacts of new technologies on rider perceptions about driver behaviors) that are critical to the introduction of safety technologies for transit, additional research questions about bus operators’ tasks, and the implications of these tasks for the design of pedestrian detection and alerting systems.
Crashworthiness Models for Automotive Batteries
Safety is a key element of electrochemical batteries that convert chemical reactions to electrical energy, especially applied to large automotive batteries in electric vehicles. High energy stored in EV battery packs translates to higher probability of fire in case of crash impact. The mechanisms leading to internal short circuit due to deformation are not well understood. This report summarizes the effort to pinpoint the critical deformation necessary to trigger a short via experimental study on large format automotive Li-ion cells. Experiments were conducted on deformation of stacks of 10 pouch cells representing the half-modules in a Ford Focus EV battery pack.
Lower Leg Biofidelity Corridors for Heel Impact
The primary purpose of this report is to develop biofidelity corridors for the small female foot/leg in axial loading. This effort built upon previous testing that was done with mid-sized male specimens. For this project, small female specimens were tested, both with and without a shoe on. The corridors developed are directly applicable to the THOR 5th female anthropomorphic test device, which is currently undergoing initial biofidelity evaluation. These biofidelity response corridors were based on anticipated measurement capabilities of typical ATDs, and include metrics such as internal tibia and fibula axial load, external footplate axial load, knee axial load, and footplate displacement. Overall, it was found that the shod corridors developed were narrower than either the combined dataset corridors or the barefoot corridors. Additionally, corridors developed with data scaled by leg-length were narrower than those developed using unscaled data. Shod, scaled corridors are recommended for use in 5thth female ATD biofidelity evaluations.
Advanced Automatic Collision Notification Research Report
This report describes NHTSA’s progress understanding the safety potential and technical considerations of post-crash automatic collision notification (ACN) and advanced automatic collision notification (AACN) technologies that send automatic notification of a crash that reached a minimum severity such as air bag deployment. Notification to a public safety answering point (PSAP, or 9-1-1 call center) or telematics service provider (TSP) occurs via cellular signal that allows the vehicle to place a call and transmit data. Research on target populations who may benefit from AACN, injury prediction, and estimates of costs and benefits/potential lives saved were included.
Structural Countermeasure Research Program
Crash test results have shown that vehicles that receive good ratings in consumer information tests still may require structural modifications for good performance in NHTSA’s frontal oblique test procedure. This study determined incremental vehicle structural change requirements and associated mass and cost in order to significantly reduce occupant compartment intrusion. The results of this report may be used to demonstrate the feasibility and cost of implementing structure countermeasures for the oblique test procedure.
WorldSID 50th Percentile Male Dummy Seating Procedure Evaluation and Revision
In 2015 NHTSA published a seating procedure for the WorldSID 50th percentile male dummy (WSID-50M) and subsequently developed a seating procedure for the THOR 50th percentile male dummy (THOR-50M). Since the THOR-50M and the WSID-50M use the same anthropometry study, the original seating procedure for the WSID-50M was revised (WSID-50M_Rev1) to reflect improvements identified during the development of the original THOR-50M seating procedure and to provide more consistency between the seating procedures for these two 50th percentile male advanced ATDs. There were revisions to the THOR-50M seating procedure being done concurrently with revisions to the WSID-50M procedure. Observations from the use of the WSID-50M_Rev1 procedure in a series of 12 crash tests, combined with revisions being made to the THOR-50M procedure, resulted in a second revision to the WSID-50M procedure, the new WSID-50M_Rev2.
Functional Safety Assessment of a Generic Accelerator Control System With Electronic Throttle Control in Gasoline-Fueled Vehicles
This report describes research to derive safety requirements related to the failures and countermeasures of the accelerator control system with electronic faults such as electronic throttle control (ACS/ETC) signals, following an industry process standard specifically in vehicles with diesel engines. This study follows the Concept Phase process in ISO)26262 and applies hazard and operability study, functional FMEA, and STPA methods. It identifies five safety goals and 204 ACS/ETC system safety requirements as well as potential opportunities to improve the risk assessment approach in ISO 26262.
An Assessment Method for Automotive Intrusion Detection System Performance
In response to the increased attack surfaces on modern vehicles due to expanded use of software and the introduction of wireless interfaces, a new market has emerged for intrusion detection systems (IDSs), which can detect some types of attacks and are under development by several companies. NHTSA requested development and demonstration of a method for assessing the in-vehicle performance of anomaly-based IDSs for vehicle data buses, specifically buses using controller area network protocols. IDSs may (1) protect vehicles from direct malicious manipulation of the data bus traffic, or (2) detect symptoms of unfriendly modification of firmware on one of the dozens of electronic control units (ECUs) on a modern vehicle’s network. The methodology used provides a means to assess the performance of automotive IDS products, to provide quantitative and qualitative analysis of performance, and to offer insights on potential IDS options.
Relative Frequency of U.S. Pedestrian Injuries Associated With Risk Measured in Component-Level Pedestrian Tests
Injury data about U.S. pedestrians was analyzed to estimate frequencies of injuries associated with impacts to vehicle components that could be tested by available component-level pedestrian test equipment. The relative frequencies of injuries that could be affected by pedestrian headform tests, upper legform tests, and lower legform tests were compared. These injuries could be reduced or mitigated if vehicle performance were improved. To determine pedestrian body regions and impacting vehicle components the tests used the same test tools and procedures defined for European New Car Assessment Programme (Euro NCAP) pedestrian testing. Vehicle components in test procedures used test zones defined for Euro NCAP pedestrian test procedures. Therefore, the real-world injuries associated upper legform component tests in this study include all cases with hip, pelvis, or thigh injuries from impact to the hood leading edge or grille. Data on the frequency of injuries by body region was drawn from pedestrian cases in the National Trauma Data Bank (NTDB) from 2007 to 2014 and the Pedestrian Crash Data Study from 1994 to 1998. Injury severity was categorized using the Abbreviated Injury Score and the Maximum Abbreviated Injury Score (MAIS) for each pedestrian.
Functional Safety Assessment Of a Generic Accelerator Control System With Electronic Throttle Control in Fuel Cell Hybrid Electric Vehicles
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 AC or DC can introduce hazards ranging from high-voltage exposure to vehicle or battery damage. The tests in this report have been independently developed based on 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.