National Highway Safety Administration Research Articles

Analyzing influencing factors of crash injury severity incorporating FARS data

The purpose of this study is to deeply analyze the influencing factors of drivers’ traffic accident casualties and reduce the occurrence of casualties. From the FARS database of the National Highway Safety Administration (NHTSA), 93248 traffic accident data were extracted as analysis samples. On this basis, the Bayesian network and multinomial logit model are established. The constructed model was tested from the perspective of model prediction accuracy and variables importance. Bayesian networks are used to analyze the interrelationships among influencing factors, and multinomial logit models are used to compare and evaluate the impact of different variables on the injury severity under different circumstances. The results show that: the prediction accuracy of the Bayesian network model and multinomial logit model is 64.57% and 65.97%, respectively. The Bayesian network reference analyses indicate that injury severity is affected by the crash factors, and there are various interactions between the various factors. The multinomial logit model analyses indicate that the factors including drivers’ age, female driver, rural roads, drunk driving, drug driving, crash time, side collision accident, etc. could significantly increase injury severity. Airbags are more effective in reducing fatal crash than injury crash. The probability of accidents caused by drug driving drivers is greater than drunk driving, drunk driving drivers are 1.79 times and 2.34 times more likely to suffer an injury severity and fatal injury severity in crashes as compared to a no injury severity, respectively, and drug driving is 1.93 times and 2.6 times, respectively. Seat belts may avoid 92.2% of fatalities. Roadside guardrail reduces the incidence of fatal crash better than injury crash. Fatal injuries severity and injury severity are 1.124 times and 1.141 times more likely to occur during the 0 : 00 to 6 : 00 as compared to no injuries, respectively, etc.

A Comparison of the Cultures and Performance of a Modern Agency and a Nineteenth-Century Agency

In this chapter of a book dedicated to the work of Jerry Mashaw, Professor Pierce compares the culture and performance of a nineteenth century agency with the culture and performance of a modern agency with an analogous mission. He concludes that the Board of Supervising Inspectors saved thousands of lives and millions of dollars by issuing scores of rules in just a few years that reduced dramatically the harm caused by the largest source of transportation accidents in the nineteenth century — steamship boiler explosions. By contrast, he notes that it took the National Highway Safety Administration (NHTSA) almost twenty years to issue the only rule that was effective in reducing the largest source of transportation deaths and injuries in the twentieth century — second collisions with automobiles. He attributes those stark differences in performance to the different cultures of the two agencies. The Board had no lawyers on its payroll, and its actions were not subject to judicial review. NHTSA was dominated by lawyers, and its actions were subject to judicial review.

Evaluating the effectiveness of active vehicle safety systems

Advanced vehicle safety systems have been widely introduced in transportation systems and are expected to enhance traffic safety. However, these technologies mainly focus on assisting individual vehicles that are equipped with them, and less effort has been made to identify the effect of vehicular technologies on the traffic stream. This study proposed a methodology to assess the effectiveness of active vehicle safety systems (AVSSs), which represent a promising technology to prevent traffic crashes and mitigate injury severity. The proposed AVSS consists of longitudinal and lateral vehicle control systems, which corresponds to the Level 2 vehicle automation presented by the National Highway Safety Administration (NHTSA). The effectiveness evaluation for the proposed technology was conducted in terms of crash potential reduction and congestion mitigation. A microscopic traffic simulator, VISSIM, was used to simulate freeway traffic stream and collect vehicle-maneuvering data. In addition, an external application program interface, VISSIM’s COM-interface, was used to implement the AVSS. A surrogate safety assessment model (SSAM) was used to derive indirect safety measures to evaluate the effectiveness of the AVSS. A 16.7-km freeway stretch between the Nakdong and Seonsan interchanges on Korean freeway 45 was selected for the simulation experiments to evaluate the effectiveness of AVSS. A total of five simulation runs for each evaluation scenario were conducted. For the non-incident conditions, the rear-end and lane-change conflicts were reduced by 78.8% and 17.3%, respectively, under the level of service (LOS) D traffic conditions. In addition, the average delay was reduced by 55.5%. However, the system’s effectiveness was weakened in the LOS A–C categories. Under incident traffic conditions, the number of rear-end conflicts was reduced by approximately 9.7%. Vehicle delays were reduced by approximately 43.9% with 100% of market penetration rate (MPR). These results imply that from the perspective of traffic operations and control to address the safety and congestion issues of a traffic stream, smarter management strategies that consider both traffic conditions and MPR are required to fully exploit the effectiveness of the AVSS in the field.

The Transformation of Auto Safety Regulation: Bureaucratic Adaptation to Legal Culture

Created in 1966 primarily as a rulemaking body empowered to force the technology of motor vehicle safety, by the late 1970's the National Highway Safety Administration (NHTSA) had largely abandoned its rulemaking mission in favor of the aggressive recall of defective motor vehicles. That first period adaptation was driven by devastating losses in pre-enforcement judicial review proceedings combined with enthusiastic judicial embrace of the agency's recall efforts. Congressional reaction mimicked the signals from the courts, and the Reagan administration's regulatory reform and relief programs of the 1980's further solidified NHTSA's revised agenda. Prodded by congressional mandates, beginning in1991, but largely of 21st century origin, NHTSA has returned to rulemaking in the last two decades, but in a largely illusory form. Rather than forcing new technologies, the agency has largely required the diffusion of existing technologies already in widespread use -- technologies that might well have reached universal deployment in the absence of the agency's rules. Recalls (which have no demonstrable effect on motor vehicle safety) have continued at increasingly high levels and have been combined with consumer information campaigns, the encouragement of state behavior modification efforts, and agency-industry agreements, to round out NHTSA's emerging model of cooperative regulation. Whether or not this strategy has substantial effects in promoting motor vehicle safety, NHTSA's accommodating posture has resulted in congressional and OMB approval and industry acceptance without litigation. This article describes the evolution of motor vehicle safety regulation and interprets the agency's transformation as an almost perfect adaptation to a legal culture skeptical of ex ante coercive restraints on individual or firm conduct and accepting of post hoc compensatory or punitive action when that conduct fails to live up to broad social norms.

Instrumentation for capture of high‐speed anatomical movement (923.1)

Objective: Describe the technique of instrumentation of the human body for capturing anatomic motion at high speed. A human body interacting with its environment is at risk for injury. Anatomic structures with viscoelastic properties do not behave in the same way at high speed. It's necessary to study these interactions when developing mechanical surrogates of the human body (crash test dummies). Way in which a crash dummy is able to replicate a human’s actual movement is called biofidelity.Methods: PMHS in this series were fresh frozen specimens thawed to room temperature. Instrumentation techniques which incorporate hardware into the spine and ribcage of the PMHS will be described. Video capture of these PMHS and the acceleration data were captured and compared in an automotive crash environment. Acceleration data filtered at industry standard and photo target tracking system compared to the post‐processed acceleration data. Force defection curves generated as well as excursion measurements for the head, thoracic spine, pelvis and lower extremities.Results: The PMHS moves similar to a live human subject in a high G environment as muscle reaction time is minimized and the baseline muscle tone is often overcome. Excursion of the PMHS head, thoracic spine and pelvis over several milliseconds shows the importance of anatomical movement in an acceleration environment.Conclusions: Instrumentation techniques have been developed. Techniques and motion capture are highly accurate and aid in developing surrogate tools for the motion of the human body for safety product development. Although PMHS do not have the baseline muscle tone of a live subject they do have realistic soft tissue strength (ligaments, tendons and other soft tissue load bearing structures). Accepted instrumentation techniques can help to describe how anatomical structures move relative to one another in environments the human body did not normally experience in it’s evolution.Grant Funding Source: National Highway Safety Administration

Effect of Military Conflicts on the Formation of Emergency Medical Services Systems Worldwide

This article briefly reviews the evolution of medical support during wars and conflicts from ancient to modern times and discusses the effect warfare has had on the development of civilian health care and emergency medical services (EMS). Medical breakthroughs and discoveries made of necessity during military conflicts have developed into new paradigms of medical care, including novel programs of triage and health assessment, emergency battlefield treatment and stabilization, anesthesia, and other surgical and emergency procedures. The critical role of organizations that provide proper emergency care to help the sick and injured both on the battlefield and in the civilian world is also highlighted.

Roof-to-ground contact force during a vehicle rollover

Current US Federal Motor Vehicle Safety Standards require that the roof strength of a vehicle must be such that it is able to withstand a quasi-static force equivalent to times the unloaded of the vehicle, with a maximum roof deformation of 5″ (127 mm). In the public forum, it is often argued that the 1.5 times the unloaded weight rule may not the most effective one for ensuring the safety of vehicle occupants. Therefore, the National Highway Safety Administration has proposed to increase the roof strength requirement to 2.5 times the unloaded of the vehicle for the available roof crush. Currently, no mechanics-based model is available in the literature dealing with the roof-to-ground contact forces when a vehicle is involved in rollover. Therefore, the current study was undertaken to develop two mechanics-based simple models, which can be used for estimating the required roof strength from the calculations of roof-to-ground contact force.

Commentary: Supersized vans: A supersized problem

Commentary: Supersized vans: A supersized problem

Smart Vehicles: New Directions for Human Factors Safety Research

Advances in technology are being incorporated in motor vehicles at an increasing pace. These technologies have applications that may improve driver safety, comfort, and convenience. Among the “Smart Vehicle” applications that have been proposed are navigation systems, near obstacle detection systems, drive-by-wire, and active suspensions. In order for these systems to be effective, they need to be designed in consonance with driver needs, capabilities, and limitations. One concern is that unless human factors issues are addressed, new technologies not only may fall short of their potential for improving safety, but also may confuse or overload the driver and reduce safety. Because of this concern, a major focus of the crash avoidance research program at the National Highway Safety Administration (NHTSA) is on human factors issues associated with new vehicle technologies. The panel will feature presentations of NHTSA perspectives and research programs followed by discussants from the private sector describing their views on human factors research needs for improving vehicle safety in the 90′s. The introductory paper will present background on current and near future research directions at NHTSA. The next presentation will describe the status of the NHTSA program to develop an advanced research simulator. The final presentation will discuss potential applications of the simulator to human factors research. The discussants will provide reactions to the research envisioned by NHTSA as well as their own perspectives on research from the private sector point of view. Two of the discussants are from the motor vehicle manufacturing industry and one has an academic/private consulting background. It is hoped that this panel will provide a broad perspective on the challenges of vehicle safety research and will stimulate new interest by human factors researchers to become involved in this important field.

Grants and Outcomes

Grants and Outcomes

Resource guide to occupant protection programs and materials.

This article lists public and private sector associations and organizations concerned with occupant protection. Many of these organizations will provide catalogues and other public information materials on occupant protection. Some have operational programs designed to influence their members in the health professions or the general public. All of the organizations have printed material available. Some provide additional resources on occupant protection such as educational kits, consumer information pamphlets, posters, written testimony, public service announcements, sample legislation, and audio visual aids useful in conjunction with health promotion program development. For information relative to state occupant protection programs, readers should contact their State Office of Highway (Traffic) Safety, Governor's Office, Regional Office of the National Highway Safety Administration, Regional Office of the Department of Health and Human Services, State Health Department or Department of Preventive Health Services, and regional or state affiliate chapters of national organizations, such as the Child Passenger Safety Associations and the National Safety Councils.