Behaviors and Attitudes
NHTSA studies behaviors and attitudes in highway safety, focusing on drivers, passengers, pedestrians, and motorcyclists. We identify and measure behaviors involved in crashes or associated with injuries, and develop and refine countermeasures to deter unsafe behaviors and promote safe alternatives.
Motorcyclists’ Attitudes on Using High-Visibility Gear To Improve Conspicuity A Study Conducted Under NCREP — The National Cooperative Research and Evaluation Program Findings From A Focus Group Study
Multi-vehicle motorcycle crash research suggests difficulty detecting motorcycles is a relevant factor. Countermeasures increase conspicuity of a motorcycle rider by wearing high-visibility gear, especially at night or in low-light conditions, yet many riders do not wear high-visibility gear. This report describes a study exploring why riders will or won’t wear high-visibility gear. Eighteen focus groups of 137 riders in Maryland, California, Texas, and Michigan discussed their attitudes, beliefs and preferences regarding high-visibility gear. The groups consisted of riders of the same gender and who ride the same motorcycle type (cruiser, touring motorcycle, or sport motorcycle). Findings revealed that a minority of participants regularly wear high-visibility gear. Primary reasons for not wearing high-visibility apparel were objections to appearance and the belief that it does not fit with their riding culture.
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.
Social Media Practices in Traffic Safety
This study researched how State Highway Safety Offices (SHSOs) are using social media, and the opportunities, benefits, and challenges social media presents. While social media continues to rapidly evolve, this report provides statistical analysis on the state of the practice of SHSO social media. It also describes new and creative ways SHSOs are sharing information, ideas, and other content – and how these activities can be measured or tracked. It provides promising practices and case study examples for using social media in traffic safety programming, and can be a tool for traffic safety programmers to design social media programs.
Mild Cognitive Impairment and Driving Performance
The objective of this project was to explore differences in driving performance and exposure between participants with mild cognitive impairment (MCI) – operationally defined through recognized clinical methods – and a comparison group of drivers of comparable age who did not meet those criteria. MCI refers to an intermediary, symptomatic state between age-appropriate cognitive decline and dementia. An initial literature review revealed a lack of clear boundaries between these cognitive status categories, which led researchers to consider continuous measures of cognitive impairment to predict road test performance and exposure. Thirty-eight participants were recruited. Clinical measures, administered by a certified driver rehabilitation specialist (CDRS), included the trail-making and maze tests, plus the Montreal Cognitive Assessment (MoCA). The Functional Activities Questionnaire (FAQ) was used to obtain participants' self-reports indicating cognitive status. A CDRS also administered the road tests in two study locations (in and near Roanoke and Richmond, Virginia). Exposure data were recorded with GPS loggers and cameras installed in participants' own vehicles for approximately one month. Regression models identified MoCA scores, and to a lesserextent Maze Test scores, as significant predictors of road test results, particularly with respect to tactical driving tasks.There were no significant regression models for analyses of exposure measures. Analysis of impairment status (not impaired, MCI, or moderate cognitive impairment) using only the MoCA classifications showed that those classified as unimpaired received significantly fewer points off on the on-road assessment than those classified as MCI, and this difference increased when comparing the unimpaired to those with any level of impairment. While the evidence was mixed regarding the extent to which MCI drivers appropriately self-restrict their exposure, MoCA appears to be a practical tool for occupational therapist generalists to use in identifying referrals for a comprehensive driving evaluation.
Older Drivers and Navigation Devices
This project examined measures related to older adults’ driving performance while they drove to a familiar destination without navigation aids, and when following new routes they had not previously driven using paper directions or an electronic navigation system (ENS), often called a “GPS.” Phase 1 also explored the effects of experience/familiarity using an ENS on driving, route-following, and manual destination entry task performance. Phase 2 explored the impact of training in ENS use on driving behavior and destination entry performance. Phase 1 found that on average all age and familiarity groups exhibited better driving performance when using the ENS compared to paper directions. The 70-and-older group members who were previously unfamiliar with the use of an ENS had the poorest driving test scores. The Phase 1 destination entry task focused on determining whether the drivers could correctly enter addresses into the device. People in their 60s performed better on this task than did those in their 70s, and participants who were familiar with ENS outperformed those who were not. Phase 2 showed that training on the use of an ENS did not improve driving performance, but did improve performance on destination entry tasks. This study suggests that ENS systems are difficult for older drivers to program, but training such as that developed for the study can improve the ability of these drivers to correctly enter destinations. Any driving performance benefits the systems may afford drivers cannot be realized if a user cann't correctly input a destination or becomes frustrated and rejects the use of the ENS device altogether.
Feasibility of Modeling the Relationship Between Seat Belt Program Inputs and Outcomes
The objective of this project was to determine the feasibility of building a model that could be used as a decision-making tool for State Highway Safety Offices (SHSOs) to help predict how resource adjustments could affect seat belt use (both positively and negatively) to avoid inadvertent negative effects on seat belt use rates and unrestrained fatalities. To accomplish this objective, the study focused on 1) exploring the existence, availability, and quality of data needed to build a useful model; 2) preparing a description of the types of models that may be worth exploring given the data that are likely available; and 3) discussing the implications of the findings for future model development.
The overall conclusion of the study was that while the available evidence points to potential feasibility, it is not clear that the input variables would provide sufficient precision to create a useful predictive model due to limitations regarding what is available to the SHSOs.
The Effects of Medical Conditions on Driving Performance: A Literature Review and Synthesis
This literature review relates changes in performance or safety outcome measures for older drivers to their medical conditions or medication use, and associated functional impairments.
Functional Safety Assessment of a Generic Accelerator Control System with Electronic Throttle Control in Gasoline Internal Combustion Engine Vehicles
This report describes research to derive safety requirements related to the failures and countermeasures of the accelerator control system (ACS) with electronic faults, such as errant electronic throttle control (ETC) signals, following an industry process standard, specifically identification of safety requirements for ACS/ETC systems in motor vehicles powered by gasoline engines. It follows the Concept Phase process of ISO 26262 and applies Hazard and Operability study, Functional Failure Modes and Effects Analysis, and Systems Theoretic Process Analysis methods. It identifies 5 vehicle-level safety goals and 179 ACS/ETC system safety requirements (an output of the ISO 26262 and STPA processes). It observes opportunities to improve the risk assessment approach in ISO 26262. DOT HS 812 557.
Impaired Driving Leadership Model: Findings Based on Three State Case Studies - Report
This report describes case studies of the Impaired-Driving Leadership Model implemented by New Mexico, Washington State and Oklahoma. Each case study highlights the process that led to each model’s implementation, elements of the model’s structure, key components of its operation, and observed impacts following implementation. The report also identifies common and distinguishing elements of each model, lessons learned, and recommendations for other States considering implementing the model. The report indicates improvements (declines) in impaired-driving fatalities over time following implementation.
Additional Analysis of National Child Restraint Use Special Study: Child Restraint Misuse (Research Note)
This Research Note is the third in a series describing installation problems of child safety seats reported by the National Child Restraint Use Special Study. This report shows that in rear-facing infant and convertible seats, the most common misuses concerned: Child under 1 year old and angle of seat is 30° or less (42% of misuse cases); loose installation (seat moves 2 inches laterally, 29%); and harness slack (15%). In forward-facing car seats, the most common misuses were the following: loose installation (47%); harness slack (28%); and harness straps behind child’s arm, back, or leg (15%). In highback and backless booster seats, the most common misuses were the following: lap belt across abdomen or ribcage (59%); and shoulder belt behind arm or back (24%).
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