Freeway speed limits and traffic fatalities in Washington State.

BACKGROUND: In 1987 individual states in the USA were allowed to raise speed limits on rural freeways from 55 to 65 mph. Analyses of the impact of the increased speed limits on highway safety have produced conflicting results. OBJECTIVE: To determine if the 1987 speed limit increase on Washington State's rural freeways affected the incidence of fatal crashes or all crashes on rural freeways, or affected average vehicle speeds or speed variance. DESIGN: An ecological study of crashes and vehicle speeds on Washington State freeways from 1974 through 1994. RESULTS: The incidence of fatal crashes more than doubled after 1987, compared with what would have been expected if there had been no speed limit increase, rate ratio 2.1 (95% confidence interval (CI), 1.6-2.7). This resulted in an excess of 26.4 deaths per year on rural freeways in Washington State. The total crash rate did not change substantially, rate ratio 1.1 (95% CI, 1.0-1.3). Average vehicle speed increased by 5.5 mph. Speed variance was not affected by the speed limit increase. CONCLUSIONS: The speed limit increase was associated with a higher fatal crash rate and more deaths on freeways in Washington State.     

Systemwide implications of the repeal of the national maximum speed limit

The adoption of higher rural interstate speed limits may shift behaviors in ways that broadly affect motor vehicle safety. In particular, these laws may attract drivers from less safe rural noninterstate roadways, implying that any negative implications of higher speed limits for rural interstate fatalities may be attenuated by fewer rural noninterstate fatalities. We test for the reallocation of vehicle miles traveled and fatalities using 1982-2002 U.S. data spanning the relaxation and repeal of the national maximum speed limit (NMSL) across all drivers and specifically those younger and older drivers associated with higher fatality risks. Overall, we find that the repeal of the NMSL resulted in a 36-37% increase in fatalities on rural interstate highways. However, we found very little support for any decrease in rural noninterstate driving or fatalities following the adoption of higher speed limits on rural interstates.     

Understanding the effect of deployment on the risk of fatal motor vehicle crashes: a nested case-control study of fatalities in Gulf War era veterans, 1991-1995

Motor vehicle crashes (MVCs) are an important cause of morbidity and premature loss of life among military personnel during peacetime and particularly following combat. A nested case-control study of fatal MVC occurring between 1991 and 1995 was conducted in a cohort of Gulf War era veterans. Cases were validated MVC deaths in the Fatality Analysis Reporting System. Controls were selected using risk set sampling by gender and year of case ascertainment in a 10:1 ratio. Preliminary results, consistent with previous reports of increased fatal MVC risk among returning combat veterans, showed a crude odds ratio of 1.45 (95% confidence interval 1.27-1.65). Multivariable logistic regression modeling was used to identify important independent predictors, as well as to quantify the influence of deployment on a risk profile for fatal MVC. Because of significant interaction between deployment and inpatient diagnosis of substance abuse, the final model was stratified by deployment status. Results suggest that demographic, military, and behavioral characteristics of deployed healthy warriors are similar to the risk profile for fatal MVC. In addition to young, single, high school-educated, enlisted male personnel, those who served during times of ground combat, particularly in infantry, gun crews, or seamanship occupations, should be targeted for preventive interventions.     

The paradox of driving speed: two adverse effects on highway accident rate

Whereas speeding is known to be a substantial risk factor in driving, there is no unequivocal evidence that accident rate on limited-access motor highways is considerably affected by average speed or by speed limits meant to regulate it. It is suggested here that the seeming puzzle actually may have a straightforward explanation: accident-prone interactions (APIs) between cars occur when they pass each other--mostly moving in the same directions or in opposite ones. Such interactions are shown here to happen more frequently, the lower average speed is. To the extent that high speed limits contribute to increase in average speed, they serve to reduce the number of such interactions, thereby to moderate at least part of the negative effect of speed on the driver's ability to avoid an impending accident.     

Characteristics of traffic crashes in Maryland (1996-1998): differences among the youngest drivers

Motor vehicle crashes (MVCs) are the leading cause of death among teenagers in the US. The present study examines how crash rates and crash characteristics differed among drivers aged 16-21 in the state of Maryland from 1996 to 1998. The results show that, based on police reports. the youngest drivers have the highest rate of MVCs per licensed driver and per annual miles driven. Furthermore, crash characteristics suggest that inexperience rather than risky driving may account for the differing rates. Drivers closer to the age of 16 had their crashes under the safest conditions: during the day in clear weather while drinking less.     

Traumatic brain injury,driver aggression and motor vehicle collisions in Canadian adults

ObjectiveThis study examines the associations between lifetime traumatic brain injury (TBI), driver aggression, and motor vehicle collisions among a population sample of adults who reside in the province of Ontario, Canada.MethodA cross-sectional sample of 3993 Ontario adults, aged 18–97 were surveyed by telephone in 2011 and 2012 as part of Center for Addiction and Mental Health’s ongoing representative survey of adult mental health and substance use in Canada. TBI was defined as trauma to the head that resulted in loss of consciousness for at least five minutes or overnight hospitalization.ResultsAn estimated 91% (95% CI: 90.0, 91.9) of individuals in this sample held a valid Ontario driver’s license at the time of testing. Among those, 16.7% reported a history of lifetime TBI and 83.3% reported no TBI. The prevalence of TBI was higher among men than women. Relative to licensed adults without TBI, adults with a history of TBI had significantly higher odds of engaging in serious driver aggression in the past 12 months, such as making threats to hurt another driver, passenger or their vehicle (AOR = 4.39). These individuals also reported significantly higher odds (AOR = 1.74) of being involved in a motor vehicle collision that resulted in hurting themselves, their passenger(s) or their vehicle.ConclusionThis is the first population-based study to demonstrate a relationship between a history of TBI and higher rates of serious driver aggression and collision involvement. Given the large proportion of adult drivers with a history of TBI, these individuals may account for a disproportion burden of all traffic safety problems. Whether the increased road safety risk of adults with a history of TBI is reflective of neurocognitive deficits or is merely evidence of a cluster of unsafe activities produced by a higher risk lifestyles requires further research attention.     

Young driver licensing: Examination of population-level rates using New Jersey’s state licensing database

Recent surveys have provided insight on the primary reasons why US teens delay licensure but are limited in their ability to estimate licensing rates and trends. State administrative licensing data are the ideal source to provide this information but have not yet been analyzed for this purpose. Our objective was to analyze New Jersey’s (NJ) licensing database to: (1) describe population-based rates of licensure among 17- to 20-year-olds, overall and by gender and zip code level indicators of household income, population density, and race/ethnicity; and (2) examine recent trends in licensure. We obtained records on all licensed NJ drivers through June 2012 from the NJ Motor Vehicle Commission’s licensing database and determined each young driver’s age at the time of intermediate and full licensure. Data from the US Census and American Community Survey were used to estimate a fixed cohort of NJ residents who turned 17 years old in 2006–2007 (n = 255,833). Licensing data were used to estimate the number of these drivers who obtained an intermediate license by each month of age (numerators) and, among those who obtained an intermediate license, time to graduation to full licensure. Overall, 40% of NJ residents—and half of those who ultimately obtained a license by age 21—were licensed within a month of NJ’s minimum licensing age of 17, 64% by their 18th birthday, and 81% by their 21st birthday. Starkly different patterns of licensure were observed by socioeconomic indicators; for example, 65% of 17-year-olds residing in the highest-income zip codes were licensed in the first month of eligibility compared with 13% of residents living in the lowest-income zip codes. The younger an individual obtained their intermediate license, the earlier they graduated to a full license. Finally, the rate and timing of licensure in NJ has been relatively stable from 2006 to 2012, with at most a 1–3% point decline in rates. These findings support the growing body of literature suggesting that teens delay licensure primarily for economic reasons and that a substantial proportion of potentially high-risk teens may be obtaining licenses outside the auspices of a graduated driver licensing system. Finally, our finding of a relatively stable trend in licensure in recent years is in contrast to national-level reports of a substantial decline in licensure rates.     

Comparing single vehicle and multivehicle fatal road crashes: A joint analysis of road conditions,time variables and driver characteristics

The difference between single vehicle crashes and multivehicle crashes was investigated in a collection of fatal crashes from six European countries. Variables with respect to road conditions, time variables, and participant characteristics were studied separately at first and then jointly in a logistic multiple regression model allowing to weigh different accounts of single vehicle as opposed to multivehicle crash occurrence.     

Acceptability and concurrent validity of measures to predict older driver involvement in motor vehicle crashes: an Emergency Department pilot case-control study

INTRODUCTION: Older drivers have one of the highest motor vehicle crash (MVC) rates per kilometer driven, largely due to the functional effects of the accumulation, and progression of age-associated medical conditions that eventually impact on fitness-to-drive. Consequently, physicians in many jurisdictions are legally mandated to report to licensing authorities patients who are judged to be medically at risk for MVCs. Unfortunately, physicians lack evidence-based tools to assess the fitness-to-drive of their older patients. This paper reports on a pilot study that examines the acceptability and association with MVC of components of a comprehensive clinical assessment battery. OBJECTIVES: To evaluate the acceptability to participants of components of a comprehensive assessment battery, and to explore potential predictors of MVC that can be employed in front-line clinical settings. METHODS: Case-control study of 10 older drivers presenting to a tertiary care hospital emergency department after involvement in an MVC and 20 age-matched controls. RESULTS: The measures tested were generally found to be acceptable to participants. Positive associations (p相似文献