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.
Investigation of Potential Design and Performance Criteria for Booster Seats Through Volunteer and Dynamic Testing
This report explores candidate booster performance metrics that have the potential to identify less effective booster systems, since current FMVSS No. 213 booster performance requirements can be met without a booster. Volunteer testing of belt fit and posture along with dynamic sled tests of booster seats was used. Posture and belt fit were measured in 24 children 4 to 12 years old, measured in three vehicles and three laboratory seating conditions. Six different booster seats, as well as the no-booster condition, were evaluated. Test conditions were also evaluated using 6YO, 10YO, and small female anthropomorphic test devices (ATDs). Minor posture differences between children and ATDs were greater in the no-booster condition and the two lower backless boosters compared to the four boosters. To provide a more realistic test environment, dynamic testing using a surrogate seat belt retractor on the most recent preliminary design update for the FMVSS No. 213 seat assembly evaluated 11 boosters as well as the no-booster condition, with six tests performed using the Hybrid III 10YO and 33 tests run with the Hybrid III 6YO.
Analysis of Pedestrian Injuries by Passenger Vehicle Model Year
This study determined if the latest generation of passenger vehicles offer better safety to pedestrians than previous generations. Using NHTSA’s State Data System data sets in 12 States, we compared the proportion of pedestrians who were injured after being struck by later-model-year vehicles (MY2011 – MY2016) with the proportion struck by earlier-model-year vehicles (MY2001 – MY2005), using three injury categories and three vehicle categories. Analyses showed that differences, though sometimes significant, were small and were inconsistent in which model year group was associated with fewer injuries.
Human Factors Research On Seat Belt Assurance Systems
This report documents a limited naturalistic field study conducted to evaluate how part-time seat belt users interact with two prototype seat belt assurance systems (SBAS), including a transmission interlock system and a speed limiter system. Data on participants' driving behavior and their interactions with the SBAS were collected and, along with subjective ratings, were used in the final analysis. The results showed statistically significant improvements in seat belt use for both SBAS types such that the percentage of unbelted driving time (or trips) significantly decreased during the treatment period as compared to the percentage of unbelted driving time (or trips) during the baseline period. This report support NHTSA's mission to save lives, prevent injuries, and reduce economic costs due to road traffic crashes, through education, research, safety standards and enforcement activity.
Li-Ion Battery Propagation Trigger Technique Development/ Igniter Development
This report describes single-cell thermal runaway initiator activities performed at Sandia National Laboratories looks at novel initiation methods applied to initiate or simulate failure of a single-cell test. As increasingly complex lithium-ion systems are used, concern has arisen surrounding thermal runaway propagation, specifically that a random field failure of a single cell could cause cascading failure of other nearby, otherwise healthy, batteries. Testing was also performed to develop a contained thermite test device. Commercial thermite materials successfully initiated thermal runaway within a single cell. To date no crucibles tested have could fully contain the thermite reaction, making this technique difficult outside of specialized testing laboratories. Ongoing work will make a final determination of the feasibility of a sealed thermite test device. Proof-of-concept testing with a near IR pulse laser was also performed, successfully initiating failure in pouch and cylindrical cells with a minimal energy input.
Stranded Energy Assessment Techniques and Tools
The report researched, developed, documented, and demonstrated RESS assessment and dis-charge procedures with enabling technology and architecture requirement, including device concepts, which may be commonly integrated into RESS designs for the safe management, removal, and handling of stranded energy of an inoperative RESS. These methods and interfaces should be applicable to both damaged and fully functional RESS systems and should comprehend both the current state-of-the-art as well as probable future directions. Non-operational environments should include service repair, end of life disassembly, vehicle crash scene (minor damage), vehicle crash scene (major damage), fire damage (e.g., garage fire), vehicle towing, and vehicle storage.
Determination of Optimal RibEye LED Locations in The WorldSID 50th Percentile Male Dummy
This report documents methods and results of testing and analysis to determine optimal locations for RibEye LEDs to measure chest deflection in the WorldSID 50th percentile male crash test dummy. This study determined that the optimal locations for the front and rear chest deflection measurements, along with the lateral-most location, which is currently measured, occur at a linear distance of 35 mm in the x direction with respect to the lateral-most location. Using these optimal measurement locations, estimated deflections resulted in a worst-case error of 9 mm and a mean error of 1.1-1.4 mm. In comparison, measuring deflection in the current tests at only a single location (lateral-most location), would have resulted in a maximum error of 23 mm, and an average error of 4.7 mm. This project supports NHTSA’s mission to reduce the number of deaths and injuries by studying how best to position chest deflection sensors to measure maximum deflection, which is used to estimate injury risk in crash tests.
Detection Response Task Evaluation for Driver Distraction Measurement for Auditory-Vocal Tasks: Experiment 2
This report supports development of driver distraction guidelines for auditory-vocal tasks. It describes driver distraction-related research performed to develop a method for measurement of the attentional demands of performing in-vehicle tasks using voice commands. An ISO standardized method called Detection Response Task (DRT) was evaluated for this purpose through an experiment conducted in a driving simulator in which participants performed voice-based in-vehicle tasks and a memory task while driving. Results showed that a DRT task implemented using a remote LED superimposed on the driving scene provided good results and a suitable task level associated with “too much” attentional demand was identified.
Review of Simulation Frameworks and Standards Related to Driving Scenarios
This reviews simulation frameworks and standards for sharing scenarios and testing methods that could be used for safely evaluating SAE Level 4 and 5 automated driving system (ADS). A simulation framework or standard should describe the object level scenario data (the positions, orientations, and velocities of all the objects in the scene) along with roadway information so that the ADS can be tested in simulation. This open framework would serve as an interface for reading and writing scenario data, allowing for development of a sharable scenario database. Such a database could aid companies, researchers, and developers in the development of ADS and in safely evaluating system performance in simulation.
Functional Safety Assessment of a Generic Accelerator Control System with Electronic Throttle Control in Hybrid Electric Vehicles with Gasoline Internal Combustion Engines
This report, one of a series of five similar reports, describes research assessing functional safety of accelerator control systems with electronic faults, such as errant electronic throttle control signals, following an industry process standard focusing specifically on errant signals in hybrid electric vehicles (HEVs) that combine an electric powertrain subsystem with a gasoline internal combustion engine. Three common HEV architectures are considered (series HEV, parallel HEV, and series-parallel HEV). This study follows the concept phase process in the ISO 26262 standard and applies a hazard and operability study, functional failure mode and effects analysis, and systems theoretic process analysis methods. In total, this study derives 8 vehicle-level safety goals and 260 safety requirements (an output of the ISO 26262 and STPA processes). This study uses the results of the analysis to identify potential opportunities to improve the risk assessment approach in the ISO 26262 standard. More than 1,500 pages of appendices are included.
Lower Beam Headlighting System Visibility Confirmation Test – Test Procedure Assessment
This report summarizes assessment of a draft test procedure for confirming visibility performance of lower beam headlighting systems, determined by activating the lower beam headlamps on a production vehicle and measuring the amount of light cast onto the forward roadway over an array of specified locations. Performance levels are then calculated based on measured values for the specified locations. Three vehicles were subjected to three sets of the test. Results showed measured values for visibility and glare measurement locations to be consistent across the three test repetitions. Overall, the test procedure was effective in characterizing lower beam performance levels and provided valuable information on headlamp illuminance consistency and indicated good test repeatability.