National Highway Transportation Safety Administration Research Articles

Effects of Advanced Driver Assistance Systems on Impact Velocity and Injury Severity: An Exploration of Data from the Crash Investigation Sampling System

This paper presents an exploratory analysis of advanced driver assistance systems (ADAS) features and safety outcomes using National Highway Transportation Safety Administration’s Crash Investigation Sampling System (CISS) database. In this database, we found improved safety outcomes associated with the presence of three ADAS features: lane departure warning, forward collision warning, and blind spot detection. In particular, vehicles with ADAS features were less likely to be involved in fatal and severe crashes than vehicles of a similar age and body style. Additionally, vehicles with ADAS features had a lower rate of change in velocity pre- and postcrash, a key proxy for injury severity. Vehicles with ADAS were also less likely to be involved in head-on and rear-end crashes than similar vehicles without ADAS and were less likely to experience a severe outcome than vehicles without ADAS when involved in sideswipe collisions. Despite these promising findings, however, small sample sizes precluded robust within-category and multivariate analysis. More robust data are urgently needed to disentangle the safety effects of ADAS features from those related to confounding variables such as vehicle age and body type for vehicle occupants, pedestrians, and bicyclists. We conclude the paper with recommendations for improvements to the CISS database that could support future investigations. We hope this work provides a baseline for scholars and practitioners to deepen our understanding of the effects of ADAS features on transportation safety.

The Long and Winding Road: 25 Years of the National Advanced Driving Simulator.

The National Advanced Driving Simulator is a high-fidelity motion-base simulator owned by the National Highway Transportation Safety Administration and managed and operated by the University of Iowa. Its 25-year history has intersected with some of the most significant developments in automotive history, such as advanced driver assistance systems like stability control and collision warning systems, and highly automated vehicles. The simulator is an application of immersive virtual reality that uses multiprojection instead of head-mounted displays. A large-excursion motion system provides realistic acceleration and rotation cues to the driver. Due to its level of immersion and realism, drivers respond to events in the simulator the same way they would in their own vehicle. We document the history and technology behind this national facility.

Implementation of Hybrid Controlled Vehicle Braking Method for the Design of Collision Avoidance Systems In Vehicles

According to data from the National Highway Transportation Safety Administration, human error is to blame for at least 90% of all car collisions. This information has intensified the focus on the design and development of collision avoidance systems in automobiles. This paper presents a semi-automated braking system to increase the accuracy of collision avoidance systems by reducing errors on the vehicle’s driver part. The methodology used combines the use of a microprocessor for analyzing data from sensors aided by servo motors, sending information to output devices for the alarm system and electric motors, and integrated circuits to implement hybridized engagement of vehicle brake. The braking system can be manually applied but can interfere and bring the vehicle to a halt once it has been determined that the driver has lost control of maneuvering the vehicle. The implemented system was able to determine the separation distances between automobiles and obstacles, give warning employing alarm set-up and engage braking at a minimum separation distance that is provided with an average response time of 0.86 s and a percentage error of 12.8% during operation. Keywords: Hybrid Controlled Vehicle Braking Method, Collision Avoidance Systems In Vehicles

Addressing the void: firearm injury prevention in the USA

Addressing the void: firearm injury prevention in the USA

Electric vehicle additive sounds: Detection results from an outdoor test for sixteen participants

Electric vehicles are significantly quieter than standard internal combustion engine vehicles. Although this is a benefit to the acoustic soundscape, it presents a safety concern, particularly to the vision impaired. Because of this, governments around the world have mandated that artificial sounds be added to electric vehicles in order to improve pedestrian safety. In the United States, these regulations are embodied in a National Highway Transportation Safety Administration document, FMVSS-141. This document provides guidance on the 1/3 octave-band frequency content, overall SPL, and measurement procedures that must be followed for a vehicle to be certified. This talk will present the results of a listener test with 16 participants who pressed a button upon detection of an approaching vehicle equipped with a FMVSS-141 compliant additive sound. Results are presented at probability of detection versus distance. This provides a unique view of the effectiveness of these sounds and additional aspects of this problem such as additive sound contribution to noise pollution and listener false alarm rates. Lastly, the talk will cover difficulties with this type of outdoor testing and recommendations for conducting them in a virtual environment.

What factors impact pedestrian and cyclist fatalities? A state level analysis

BackgroundPedestrian and bicyclist injuries and fatalities have increased since 2010 after a long downward trend. Trucks and SUVs, collectively called light trucks, have also increased in sales and size, which may affect pedestrians and bicyclists. Additionally, pedestrian and cyclist commuters vary by state and it has been speculated that an increase in such commuters may affect fatalities. Studying vulnerable road users can bestow clues on best practices for infrastructure and public health.MethodsState level pedestrian and cyclist fatality data was obtained from the National Highway Transportation Safety Administration for 2018. Light truck registration by state was obtained from the Office of Highway Policy Information for 2018. Commuters who walk or bike to work were obtained from the American Community Survey from 2009 to 2011, from the latest Centers for Disease Control report. We performed multiple linear regression, accounting for total motor vehicle lane miles per 100 people, also obtained from the Office of Highway Policy Information for 2018. Multiple regression analysis was performed to assess predictors for pedestrian and cyclist fatalities with the predictors variables of light truck registration, lane miles per 100 people, and proportion of commuters who are vulnerable road users. Secondary analysis included simple linear regression of the predictor variables against each other.ResultsThe multiple regression model, including proportion of light truck registration, lane miles per 100 people, and proportion of commuters who are vulnerable road users, accounted for 18% of the variability in the outcome variable (p = 0.03). An increased number of vulnerable road users were negatively associated with pedestrian and bicyclist fatality. Additionally, there appeared to be an association between motor vehicle lane miles per 100 people and proportion of light truck registrations that was also significant (p < 0.01).ConclusionThe variables affecting vulnerable road user deaths are important to understand given their increased risk exposure on the road. This state level study identifies a potential protective variable with increased vulnerable road users being associated with a decrease in pedestrian and bicyclist death rates. Additionally, light truck proportions do not appear to have a significant effect on death rates.

MOTORCYCLE HELMET USE AND FATALITIES IN THE SOUTHEAST REGION OF THE USA

Introduction: The federal government estimates that per mile traveled in 2018, the number of deaths on motorcycles was nearly 27 times the number in cars. In the United States there is no universal helmet law. In twenty-two states, motorcycle helmets are entirely optional, while in nineteen states and the District of Columbia universal motorcycle helmets laws requiring helmets for all riders regardless of age are implemented and nine states only require younger motorcycle riders to wear a helmet, with varying age limits. Objectives: The overall objectives of this study were to evaluate the following: (1) number of fatalities (with and without helmet use), (2) fatality rate per motorcycle registration, (3) fatality percentage with age, (4) percent fatality due to alcohol impairment, and (5) location of collision impact to the rider in two southern states (Mississippi and Alabama) where helmet laws are established compared with a southern state (Florida) that only requires riders less than 20 years of age to be helmeted. Methods: Data from 2015-2018 were obtained from the National Highway Transportation Safety Administration Reporting System (FARS) and supplemented with state related and CDC data. Results: In all three states, the most common collision was a front-end impact. Mississippi had the highest percentage of motorcycle fatalities even with &gt;80% of riders helmeted when the fatal accident occurred, followed by Florida motorcyclist who are only 50% of the time helmeted. In all three southern states similar percentage of fatalities were seen in each age group with higher fatalities associated with age range of 30-39 years. Conclusions: Variables such as helmet type, distance from a level 1 trauma center, poor roads, weather conditions, and visibility of the rider may also be factors that contribute to a higher incidence of fatality and need to be further investigated to improve motorcycle safety.

Predictive modeling of maximum injury severity and potential economic cost in a car accident based on the General Estimates System data

In this paper, we aim to identify the significant variables that contribute to the injury severity level of the person in the car when an accident happens and build a statistical model for predicting the maximum injury severity level as well as estimating the potential economic cost in a car accident based on those variables. The General Estimates System data, which is a representative sample of police-reported motor vehicle crashes of all types collected by the National Highway Transportation Safety Administration, from the years 2012 to 2013 is the main data source. Some other data sources such as the car safety rating from the United State Department of Transformation and the state-specific cost of crash deaths fact sheets are also used in the predictive model building process. An interactive system programmed in HyperText Markup Language, Cascading Style Sheets and JavaScript is developed based on the results of predictive modeling. The system is hosted on a website at http://gessmu.azurewebsites.net for public access. The system allows users to input variables that are significant contributors in car accidents and obtain the predicted maximum injury severity level and potential economic cost of a car accident.

The 2016 Data Challenge of the American Statistical Association

The Sections on Statistical Graphics and Statistical Computing of the American Statistical Association have a long history of issuing Data Challenges with the first one starting in 1982/1983. The challenge is now an annual event where most of them use data collected and disseminated by the U.S. government. The data set for the 2016 Data Challenge was the Department of Transportation’s General Estimates System. The GES is collected by the National Highway Transportation Safety Administration and is a representative sample of police-reported motor vehicle crashes. This editorial introduces the five papers submitted by contestants in the data challenge.

Injury metrics are altered in spica-casted versus non-casted child ATDs in side-impact collisions with door intrusion

Objective: There is little data defining safe transport protocols for spica-casted children. A single earlier study demonstrated the presence of a body cast alters kinematics and injury metrics during simulated side-impact crashes. Since then, the National Highway Transportation Safety Administration (NHTSA) proposed a new side-impact test protocol for evaluating child restraints. This test is more severe than the earlier tests, as it simulates an impact with a door intruding into the occupant space. As no currently available child restraint system (CRS) able to accommodate a spica-casted child has been evaluated using these updated testing criteria, the objective of this study was to evaluate current restraint options in simulated side-impact collisions using an anthropomorphic test device (ATD) modeled after a 3-year-old.Methods: Four commercially available CRSs able to accommodate a spica-casted Q3s side-impact ATD were selected for testing. Side-impact testing was performed using casted and uncasted ATDs in compliance with the NHTSA proposed side-impact test. High-speed photography and ATD instrumentation were used to measure selected injury criteria.Results: HIC15 values were highest in CRSs with less robust side wings, such as the Merritt WallenburgTM (HIC15 = 1,373), which allow for the occupant to interact with the intruding door panel. Head contact with the door panel was found to correspond with high resultant neck peak force. Pelvic acceleration magnitudes were greatest for the uncasted tests. Casted tests with a CRS that included an armrest were associated with greater torso rotation in the frontal plane with the left shoulder moving toward the door panel.Conclusions: The presence of a spica cast alters injury metrics in side-impact testing. Spica specific child safety seats are not yet optimized for side-impact with door intrusion. This is due to a lack of adequate side cushion wings, which may place both casted and uncasted occupants at increased likelihood for injury through head contact with an intruding door. Additional work is needed to improve the safety of CRSs for both casted and uncasted children in side-impact collisions.

Pediatric Injury Prevention, the EMSC, and the CDC

Injuries are the leading cause of death and disability in children 1-18 years old in the United States, and many of these injuries are preventable. The Haddon matrix is a foundational concept of injury prevention, examining different phases and factors of the injury process to develop interventions. Primary prevention, including injury prevention, is the first phase of the Emergency Medical Services for Children continuum of care. As part of this continuum, the National Highway Transportation Safety Administration and the Centers for Disease Control and Prevention are integral components of the national prevention efforts to decrease unintentional injuries due to motor vehicle crashes and home and recreational injuries as well as intentional injuries. This article describes a brief history of the Emergency Medical Services for Children, National Highway Transportation Safety Administration, and the Centers for Disease Control and Prevention, as well as injury prevention initiatives for some of the leading causes of pediatric injuries and child maltreatment.

Hands on the Wheel: A Call for Greater Regulation of Semi-Autonomous Cars

The United States is in the midst of a driverless car revolution. Semi-autonomous cars — those that can steer, accelerate, and brake on their own under certain circumstances — are already available to consumers. Fully autonomous cars will be available within the decade. The federal government and states throughout the nation have responded to these developments by rushing to pass laws designed to regulate the fully autonomous cars that are coming while largely ignoring the semi-autonomous cars that are already on U.S. roads. This is an extremely troubling oversight. New studies suggest that semi-autonomous vehicles are likely far more dangerous than the fully autonomous vehicles being developed. Indeed, despite the fact that semi-autonomous vehicles rely on continuous human supervision to operate safely, a growing body of research demonstrates that drivers of semi-autonomous vehicles are highly prone to distraction and may have significant misunderstandings of the capabilities and limitations of these vehicles. Both the federal government and states should pass laws and regulations designed to address these safety issues. Namely, the federal government should: (1) grant the National Highway Transportation Safety Administration the ability to create and administer a pre-market approval system for autonomous vehicles, (2) require car manufacturers to install attention warning systems on semi-autonomous cars in order to minimize the risk of driver distraction, and (3) place restrictions on the ability of manufacturers to give the semi-autonomous features on their cars names like “Autopilot” that might mislead consumers as to their capabilities. States, in turn, should (1) forbid drivers from tampering with or disabling driver monitoring systems, (2) require owners of semi-autonomous cars to install routine over-the-air software updates that make these vehicles safer, and (3) mandate that drivers of these vehicles complete proper driver training.

Proactive privacy for a driverless age

Autonomous vehicles are on the cusp of disrupting the entire transportation industry and current privacy legislation is not yet equipped to deal with the changes being spurred by this innovation. This paper enumerates and elucidates on the various privacy concerns that are specific autonomous vehicles. It also proposes the principles of “Privacy-by-Design”, an industry trend pertaining to other arenas of privacy, be adapted and used for regulating privacy around autonomous vehicles. It calls for the NHTSA (National Highway Transportation Safety Administration), with guidance from the FCC, and the FTC, to use their expertise in creating administrative rules that will protect the privacy of the public. Having learned valuable lessons from recent privacy concerns in the mobile device industry, the Privacy-by-Design approach would help ease the transition into this useful, but potentially intrusive technology. Currently, privacy is receiving significant attention in publications, but with autonomous vehicles being a nascent industry, there is very little being said about the privacy concerns specifically pertaining to these technology autonomous vehicles. Recent strides in the technology and the legislative acceptance of these vehicles have made them a widely discussed topic, and thus makes a thorough discussion of privacy related specifically to this technology both timely and relevant. This paper provides an early assessment of an area of concern that is growing as rapidly as are autonomous vehicles. The technology is being proven effective and safe, so the real focus will shift to use concerns, like privacy. The autonomous vehicle industry is still early in its development, and there is imminent opportunity to anchor privacy into the fundamentals of autonomous vehicles, preempting numerous potential infringements.

In Memoriam: Carol Stroebel.

It is with very heavy hearts that the board and staff of the Children’s Environmental Health Network (CEHN) announce the loss of our long-time colleague, champion, and friend Carol Stroebel. Carol, of Winchester, Virginia, passed away surrounded by loved ones on 16 January 2016.

Injury severity data for front and second row passengers in frontal crashes.

The data contained here were obtained from the National Highway Transportation Safety Administration׳s National Automotive Sampling System – Crashworthiness Data System (NASS-CDS) for the years 2008–2014. This publically available data set monitors motor vehicle crashes in the United States, using a stratified random sample frame, resulting in information on approximately 5000 crashes each year that can be utilized to create national estimates for crashes. The NASS-CDS data sets document vehicle, crash, and occupant factors. These data can be utilized to examine public health, law enforcement, roadway planning, and vehicle design issues. The data provided in this brief are a subset of crash events and occupants. The crashes provided are exclusively frontal crashes. Within these crashes, only restrained occupants who were seated in the right front seat position or the second row outboard seat positions were included. The front row and second row data sets were utilized to construct occupant pairs crashes where both a right front seat occupant and a second row occupant were available. Both unpaired and paired data sets are provided in this brief.

Restraint use in motor vehicle crash fatalities in children 0 year to 9 years old.

Despite improvements in child passenger safety legislation and equipment, motor vehicle crashes (MVCs) continue to be the leading cause of death in children younger than 10 years. The objective of this study was to describe factors associated with restraint use in fatal MVC in children 0 year to 9 years old. The Fatality Analysis Reporting System, maintained by the National Highway Transportation Safety Administration, was used to obtain data on MVC fatalities from 2001 to 2010 in children 0 year to 9 years old. The main outcome was restraint use. Demographic information (age, sex, and race) and crash characteristics including vehicle type (sedan, van, truck, sports utility vehicle) and seat position in the vehicle were analyzed with the χ statistic to evaluate these factors for any restraint use compared with no restraint use in MVC fatalities. There were 7,625 MVC fatalities in children 0 year to 9 years old from 2001 to 2010.Among these fatalities, 4,041 (53%) had any restraint use. Front seat passengers accounted for 20.9% (1,595 of 7,625) of the fatalities. Children 0 year to 3 years old had a higher proportion of restraint use than children 4 years to 9 years old (p < 0.001). White children compared with black children had higher use of restraints (p < 0.001). Children riding in sedans/vans compared with sport utility vehicles/trucks and those riding in the rear seats of the vehicle compared with those in front seats were significantly more likely to use restraints (p < 0.001). Overall, only half of children 0 year to 9 years old who died in an MVC were wearing any child restraint in the vehicle, and 20% were sitting in the front seat. Continued efforts must be made to enforce legislation and educate the public about best practices regarding child passenger safety to improve proper restraint use and to decrease MVC fatalities in children. Prognostic/epidemiologic study, level II.

State-level differences in fatal law enforcement officer collisions

Purpose– The purpose of this paper is to investigate variability in law enforcement officer (LEO) traffic fatality rates among states in order to identify policy-relevant areas of opportunity to reduce deaths.Design/methodology/approach– Differences in state highway spending, regulatory policy, law enforcement training, LEO and general public traffic fatalities, and other state-level variables are explored through cross-sectional regression analysis and qualitative content analysis. Data were used from the Federal Bureau of Investigation Crime in the USA and LEOs Killed and Assaulted reports, and the National Highway Transportation Safety Administration Fatality Analysis Reporting System, among other sources.Findings– There are a number of significant state-level variables and trends that contribute to differences in LEO traffic fatality rates. Maximum highway speed limits and general population traffic fatalities are found to be statistically significant predictors. Thematic factors relating to LEO exceptionalism, agency sovereignty, training, and external control loci, emerged through qualitative analysis.Research limitations/implications– Limitations included differences in definition, consistency, and reporting among data sources. Qualitative analysis of some variables were limited and future research should pursue more robust and repeated/longitudinal measures.Practical implications– Policymakers have an opportunity to review significant factors contributing to higher/lower collision involvement rates and make changes to police practices to reduce collision involvement and improve safety for LEOs.Originality/value– No prior study has offered a national, cross-case analysis of LEO traffic fatalities by state. This paper offers law enforcement policymakers empirical examples of successful LEO traffic safety policies.

Then &amp; now: trends in fatal law enforcement traffic collisions

Purpose – The purpose of this paper is to analyze trends in fatal law enforcement officer (LEO) traffic collisions and describes prior research approaches and industry responses. It reviews the issue from historical and contemporary perspectives and details its problems for public policy. Design/methodology/approach – Descriptive statistics are applied to data primarily covering the period 1995 to 2010 contained in the Federal Bureau of Investigation Crime in the USA and LEO Killed and Assaulted reports and the National Highway Transportation Safety Administration Fatality Analysis Reporting System database. Trends are established and comparisons are offered between groups. Findings – Traffic collisions are the leading cause of death for LEOs. Traffic fatalities in the general public have steadily decreased in past decades. This has not been the trend among LEOs. This issue has been studied from several disciplinary perspectives in the social, cognitive, biological, engineering, and natural sciences. While the law enforcement industry has documented the trend, concerted efforts to mitigate the issue have been limited until recently. Practical implications – Law enforcement practitioners and policymakers should take note of research findings and pursue training, policy, and practice changes to limit LEO traffic fatalities and effect an improvement trend consistent with the national reduction in highway deaths. Originality/value – This paper brings together previously uncoupled data sources and prior research to identify problematic trends and contextualize LEO traffic fatalities as a subset of all traffic fatalities. It provides law enforcement policymakers a stark and revealing assessment of the most dangerous aspect of their field.

Resurrecting Driver Workload Metrics: A Multivariate Approach

This paper presents new, multivariate analyses of data collected during the Driver Workload Metrics (DWM) project. In a cooperative effort with the National Highway Transportation Safety Administration, the DWM project had several goals including the development of performance metrics and test procedures to assess visual, manual, and cognitive aspects of driver workload. Workload was defined as the competition in driver resources (perceptual, cognitive, or physical) between the driving task and a concurrent secondary task, occurring over that task's duration. It was hypothesized that, depending on the type of secondary task performed while driving, measured workload and the correlated quality of driving should either remain the same or decline, but would manifest in degraded measures of lane keeping, longitudinal control, or eye glance behavior. However, the original DWM project had an unrealized goal, i.e. to apply Exploratory Factor Analysis (EFA) methods, in an attempt to uncover the underlying unobserved structure within the project's relatively large set of variables. It is this hidden multi-dimensional structure that must be examined to empirically comprehend the concept of driver workload. DWM kinematic vehicle data, driving performance, and eye glance data were analyzed using Maximum Likelihood Factor Analysis (MLFA). These analyses found that task-induced workload affected driving performance and was multi-dimensional in nature. Visual-manual tasks exhibited fundamentally different performance profiles than auditory-vocal tasks or just driving. Furthermore, when secondary statistical analyses of the normalized factor scores were done using Multivariate Analysis of Variance (MANOVA) the results found highly statistically significant workload differences in age groups, task type, and at times, gender.

Neck Injury Criteria Formulation and Injury Risk Curves for the Ejection Environment: A Pilot Study

Helmet mounted displays provide increased pilot capability, but can also increase the risk of injury during ejection. The National Highway Transportation Safety Administration's (NHTSA's) neck injury criteria (Nij) metric is evaluated for understanding the impact of helmet mass on the risk of injury and modified risk curves are developed which are compatible with the needs of the aviation community. Existent human subject data collected under various accelerative and head loading conditions were applied to understand the sensitivity of the Nij construct to changes in acceleration and helmet mass, as well as its stability with respect to gender, body mass, neck circumference, and sitting height. A portion of this data was combined with data from an earlier postmortem human subject study to create pilot study modified risk curves. These curves were compared and contrasted with the NHTSA risk curves. A statistically significant difference in the peak mean Nij was observed when seat acceleration increased by 2 G, but not when helmet mass was varied from 1.6 kg to 2 kg at a constant seat acceleration of 8 G. Although NHTSA risk curves predict a 13% risk of AIS 2+ injury for the 8-G, 2-kg helmet condition mean Nij of 0.138, no AIS 2+ injuries were observed. Modified risk curves were produced which predict a 0.91% risk of AIS 2+ injury under these conditions. The Nij was shown to be sensitive to changes in acceleration and generally robust to anthropometric differences between individuals. Modified risk curves are proposed which improve risk prediction at lower Nij values.