Vehicle Mortality Research Articles

An Emerging Racial Disparity in US Motor Vehicle Fatalities

This cohort study examines an increase in motor vehicle fatality rates for Black individuals in the US beginning in 2014 compared with White individuals.

Mandatory Vision Test for Driver License Renewal in Association With Traffic Fatality and Injury Among Older Road Users in Utah.

In 2011, Utah began requiring that drivers aged 65years and older pass a vision test at each license renewal. This study aims to investigate if the mandatory vision test associated with motor vehicle fatality and injury rates in older road users. We fit controlled interrupted time series analysis models to compare fatality and injury rates for older adults (65+) affected by the law to younger adults (45-64) unaffected by the law. The models yielded estimates of differential level and slope changes in fatality and injury rates, which we used to estimate policy associations. We did not find evidence that implementing an accelerated vision test for older adults in Utah was associated with a reduction in injury or fatality rates among older (65+) drivers and non-drivers relative to those aged 45-64. Other strategies might be considered to prevent fatal motor vehicle crashes (MVCs) in older adults.

The association between marijuana and motor vehicle crashes

IntroductionWe are just beginning to be able to detect the policy implications and public health effects of changes in marijuana laws and consumption in the United States on motor vehicle related fatalities. Most studies to date use classical regression methods to study these and are thus susceptible to both model and parameter uncertainty. This study examines the associations between marijuana and motor vehicle fatality rates taking these two issues of uncertainty into account using Bayesian sturdy-values, i.e., s-values. MethodThis study utilizes a new balanced panel dataset across all states and Washington, D.C. for the period 2010 to 2016 in the context of linear models using Bayesian s-values. It addresses the association between marijuana and alcohol consumption along with the legal environment across states and through time on crash fatalities. Other important factors such as the distractive influence of cell phones are studied. The s-value approach considers a vast number of model specifications and provides robust policy guidelines. ResultsA strong association between marijuana and alcohol use on motor vehicle crash rates is found. The statistical results are both substantial and robust, i.e., non-fragile. Other important variables include cell phone use, seat belt use, speed limit laws, and fleet modernization. ConclusionOur results have found strong evidence of a life-taking relationship between marijuana use and vehicle crashes. This suggests that policy makers recognize that legislation liberalizing marijuana use may have tragic ramifications regarding motor vehicle fatalities.

Trends and disparities in American Indian/Alaska Native unintentional injury mortality from 1999 to 2016

IntroductionAlcohol and drug use are significant problems in the US, and American Indian/Alaska Native (AI/AN) communities and individuals are known to be among the most affected. This study evaluates disparities...

Vehicle size choice and automobile externalities: A dynamic analysis

We study the effect of highway congestion on the “arms race” on American roads, which has led to larger and more powerful vehicles that reduce safety and increase fuel consumption. We develop a new methodology to estimate a dynamic vehicle size choice and replacement model and find that congestion delays affect vehicle sizes. We then show that by addressing complementary externalities – congestion and the externalities associated with larger vehicle sizes – congestion pricing could reduce the vehicle fatality rate, generating $25 billion in annual benefits, and could improve vehicle fleet fuel efficiency, generating roughly $10 billion in annual operating cost savings.

The impact of state laws on motor vehicle fatality rates, 1999-2015.

Motor vehicle crash (MVC) fatalities have been declining while states passed various legislation targeting driver behaviors. This study assesses the impact of state laws on MVC fatality rates to determine which laws were effective. Publically available data were collected on driver-related motor vehicle laws, law strengths, enactment years, and numbers of verified-trauma centers. Prospective data on crash characteristics and MVC fatalities 16 years or older from Fatality Analysis Reporting System 1999 to 2015 (n = 850) were obtained. Generalize Linear Autoregressive Modeling was used to assess the relative contribution of state laws to the crude MVC fatality rate while controlling for other factors. Lowering the minimum blood alcohol content (BAC) was associated with largest declines for all ages, especially the older cohorts: 16 years to 20 years (B = 0.23; p < 0.001), 21 years to 55 years (B = 1.7; p < 0.001); 56 years to 65 years (B = 3.2; p < 0.001); older than 65 years (B = 4.1; p < 0.001). Other driving under the influence laws were also significant. Per se BAC laws accompanying a reduced BAC further contributed to declines in crude fatality rates: 21 years to 55 years (B = -0.13; p < 0.001); older than 65 years (B = -0.17; p < 0.05). Driving under the influence laws enhancing the penalties, making revocation automatic, or targeting social hosts had mixed effects by age. Increased enforcement, mandatory education, vehicle impoundment, interlock devices, and underage alcohol laws showed no association with declining mortality rates. Red light camera and seatbelt laws were associated with declines in mortality rates for all ages except for older than 65 years cohort, but speed camera laws had no effect. Graduated Driver License laws were associated with declines for 16 years to 21 years (B = -0.06; p < 0.001) only. Laws targeting specific risks (elderly, motorcycles, marijuana) showed no effect on declining MVC mortality rates during the study period. States have passed a wide variety of laws with varying effectiveness. A few key laws, specifically laws lowering allowable BAC, implementing red light cameras, and mandating seatbelt use significantly reduced MVC mortality rates from 1999 to 2015. Simply adding more laws/penalties may not equate directly to lives saved. Continued research on state laws will better inform policy makers to meet evolving public health needs in the management of MVC fatalities. Epidemiological, Level III.

Context and culture: Reasons young adults drink and drive in rural America

Montana, a large and rural U.S. state, has a motor vehicle fatality rate almost double the national average. For young adults, the alcohol-related motor vehicle fatality rate in the state is almost three times the national average. Yet little research has explored the underlying reasons that young people in rural areas drink and drive. Drawing from the theory of triadic influence (TTI) and a series of qualitative focus group discussions, the current study examined how aspects of the landscape and culture of rural America promote and hinder drinking and driving among young people. In 2015 and 2016, 72 young adults (36 females) aged 18–25 years old (mean age = 20.2) participated in 11 semi-structured focus groups in 8 rural counties in Montana. Discussions were transcribed, and two reviewers independently coded text segments. Themes were identified and an inductive explanatory model was created. The results demonstrated that aspects of the social context (e.g., peer pressure and parental modeling), rural cultural values (e.g., independence, stoicism, and social cohesion), and the legal and physical environment (e.g., minimal police presence, sparse population, and no alternative transportation) promoted drinking and driving. The results also identified salient protective factors in each of these domains. Our findings demonstrate the importance of examining underlying distal determinants of drinking and driving. Furthermore, they suggest that future research and interventions should consider the complex ways in which cultural values and environmental factors intersect to shape the risky health behaviors of rural populations.

Availability and consistency of health and non-health data for road traffic fatality: Analysis of data from 195 countries, 1985–2013

High-quality data are critical for validly monitoring progress toward global initiatives related to road traffic crash prevention. We assessed the availability and consistency of road traffic mortality data from health and non-health departments in national governments, plus changes in data consistency over time from 1985 to 2013. Using freely accessible data, we systematically assessed availability and consistency of health and non-health data from 1985 to 2013 in 195 countries. Data availability was reflected by the presence of data on motor vehicle mortality rates in that country at any points between 1985 and 2013. The ratio of ‘health data divided by non-health data’ was calculated to measure the consistency of the two types of data sources. We found that 77 of the 195 countries in the world (39%) had both health and non-health data sources available from 1985 to 2013. None of the 34 low-income countries had both kinds of data sources simultaneously available, while 41 of 55 high-income countries had both kinds of data sources. Of the 71 countries having both kinds of data for five years or more, 33 countries demonstrated high consistency between data sources, 25 countries showed moderate data consistency, and 13 countries displayed low consistency. Jamaica, Mexico, and China had the largest data inconsistencies. 26 of the 71 countries witnessed improved data consistency between 1985 and 2013, but nine experienced decreasing data consistency, in a few cases to a large degree. Efforts are needed to identify reasons leading to data quality changes, and to develop approaches to improve data quality in those nations where it is inadequate.

The likelihood of achieving quantified road safety targets: A binary logistic regression model for possible factors

In past several decades, many countries have set quantified road safety targets to motivate transport authorities to develop systematic road safety strategies and measures and facilitate the achievement of continuous road safety improvement. Studies have been conducted to evaluate the association between the setting of quantified road safety targets and road fatality reduction, in both the short and long run, by comparing road fatalities before and after the implementation of a quantified road safety target. However, not much work has been done to evaluate whether the quantified road safety targets are actually achieved. In this study, we used a binary logistic regression model to examine the factors – including vehicle ownership, fatality rate, and national income, in addition to level of ambition and duration of target – that contribute to a target’s success. We analyzed 55 quantified road safety targets set by 29 countries from 1981 to 2009, and the results indicate that targets that are in progress and with lower level of ambitions had a higher likelihood of eventually being achieved. Moreover, possible interaction effects on the association between level of ambition and the likelihood of success are also revealed.

The effect of cell phones on international motor vehicle fatality rates: A panel-data analysis

This paper analyzes the effects of cell phone usage and economic freedom on motor vehicle death rates by estimating regression models on data for three years across 38 countries. The models incorporate a representative set of motor vehicle fatality determinants. Results indicate that cell phone use has a statistically significant nonlinear impact on highway death rates and that economic freedom does not appear to have an effect.

Estimating the consequences of multiple threats and management strategies for semi‐aquatic turtles

Summary Roads are pervasive fixtures on most landscapes but are typically among many factors contributing to wildlife population declines. Addressing road mortality as part of larger conservation efforts is challenging because it can be difficult to measure per capita mortality from roads and other concurrent threats. We used 4 years of mark–recapture–recovery data for diamondback terrapins Malaclemys terrapin on a causeway in Georgia, USA, to directly estimate threats of adult road mortality and nest predation, contrast the consequences to population growth using stage‐based matrix models and make management recommendations to stabilize the population. Mean estimated annual adult road mortality was 11·1% (range = 4·4–16·4%). Estimated annual nest predation was 61·9%. We estimated that the population was declining (λ &lt; 0·98) in all scenarios where both threats were included. Variation in adult survival was the most influential (highest elasticity) contributor to population growth relative to other demographic rates; however, λ would remain below 1 with any nest predation rate exceeding our estimate even if actions to mitigate road mortality were 100% effective. Synthesis and applications. Our study provides some of the first direct estimates of vehicle mortality rates and shows that mortality can remain sufficiently high among years to cause population declines. We also demonstrate that management actions focused on singular threats are inadequate for recovering populations. We conclude that integrated road and predator management is necessary to conserve turtle populations, and we suggest alternative strategies to compensate for some vehicle mortality and nest depredation.

Variation in U.S. traffic safety policy environments and motor vehicle fatalities 1980–2010

ObjectiveTo examine the impact of variation in state laws governing traffic safety on motor vehicle fatalities. Study designRepeated cross sectional time series design. MethodsFixed effects regression models estimate the relationship between state motor vehicle fatality rates and the strength of the state law environment for 50 states, 1980–2010. The strength of the state policy environment is measured by calculating the proportion of a set of 27 evidence-based laws in place each year. The effect of alcohol consumption on motor vehicle fatalities is estimated using a subset of alcohol laws as instrumental variables. ResultsOnce other risk factors are controlled in statistical models, states with stronger regulation of safer driving and driver/passenger protections had significantly lower motor vehicle fatality rates for all ages. Alcohol consumption was strongly associated with higher MVC death rates, as were state unemployment rates. ConclusionsEncouraging laggard states to adopt the full range of available laws could significantly reduce preventable traffic-related deaths in the U.S. – especially those among younger individuals. Estimating the relationship between different policy environments and health outcomes can quantify the result of policy gaps.

The Dependence of Reported Homicide Rates on Reported Non-Motor Vehicle Accident Death Rates in US Young Children and Infants, 1940-2007

An analysis of the relationship between reported homicides and reported non-motor vehicle accident deaths in young children and infants was performed. Reported young child (aged 1 to less than 5 years) and infant (aged less than 1 year) homicide and non-motor vehicle accident mortality rates in boys and girls in the United States from 1940 to 2007 were analyzed using the 4-parameter logistic model. Homicide rate growth over time displayed sigmoid curves with inflection points near 1968 in young children and near 1984 in infants. Using the maximum and minimum homicide rate asymptotes from those analyses over time, 4-parameter logistic model between homicide rates and non-motor vehicle mortality rates suggests that 84.2% and 94.2% of the variation in young child homicide rates, in boys and girls respectively, can be explained by variation in the corresponding non-motor vehicle accident mortality rates and that 69.4% and 66.3% of the variation in infant homicide rates, in boys and girls respectively, was explained by variation in the corresponding non-motor vehicle accident mortality rates. These findings are consistent with the thesis that changing propensities in the classification of young child and infant deaths as either homicides or non-motor vehicle accident deaths, rather than actual changes in societal violence, may explain a substantial proportion of the reported increases in homicide rates in young children and infants. Moreover, the observation that increases in homicide rates in young children and infants were separated in time by nearly 16 years further supports this thesis.

Motor vehicle fatalities among oil and gas extraction workers

Motor vehicle crashes are the leading cause of work-related fatality in the U.S. as well as in the oil and gas extraction industry. This study describes the characteristics of motor vehicle-related fatalities in the oil and gas extraction industry using data from the U.S. Bureau of Labor Statistics’ Census of Fatal Occupational Injuries. It compares the risk of dying in a motor vehicle crash in this industry to other major industries and among different types and sizes of oil and gas extraction companies. There were 202 oil and gas extraction workers who died in a work-related motor vehicle crash from 2003 to 2009. The motor vehicle fatality rate for workers in this industry was 8.5 times that of all private wage and salary workers (7.6 vs. 0.9, p<.0001). Workers from small oil and gas establishments (<20 workers) and workers from well-servicing companies were at greatest risk of dying in a motor vehicle crash. Pick-up trucks were the most frequent type of vehicle occupied by the fatally injured worker (n=104, 51.5%). Safety belt non-use was identified in 38.1% (n=77) of the cases. Increased focus on motor vehicle safety in this industry is needed, in particular among small establishments. Extraction workers who drive light duty vehicles need to be a specific focus.

State-Specific ATV-Related Fatality Rates: An Update in the New Millennium

We compared state-specific all-terrain vehicle (ATV) fatality rates from 2000-2007 with 1990-1999 data, grouping states according to helmet, training, and licensure requirements. We used the CDC WONDER online database to identify ATV cases from 2000-2007 and calculate rates per 100,000 population by state, gender, and age. ATV deaths (n=7,231) occurred at a rate of 0.32 per 100,000 population. Males accounted for 86% of ATV-related deaths at a rate that was six times that for females (0.55 vs. 0.09 per 100,000 population, respectively); 60% of the male deaths occurred in the 15- to 44-year age group. With the exception of the two oldest age categories, rates were consistently higher in the no-helmet-law group. Both the number and rate of ATV-related deaths increased more than threefold between 1990-1999 and 2000-2007. West Virginia and Alaska continue to have the highest ATV fatality rates (1.63 and 2.67 ATV deaths per 100,000 population, respectively). Helmet-use requirements seem to slightly mitigate ATV-related death, but training requirements do not. For policy to be effective, it must be enforced.

Modeling road traffic fatalities in India: Smeed's law, time invariance and regional specificity

Mathematical formulations linking road traffic fatalities to vehicle ownership, regional population, and economic growth continue to be developed against the backdrop of Smeed and Andreassen models. Though a few attempts were made, Smeed's law has not been fully tested in India. Using the 1991–2009 panel data from all states, this work (a) developed the generalized Smeed and Andreassen models; (b) evaluated if traffic fatalities were impacted by structural changes; and (c) examined if – in relation to the generalized model – the individual (time and regional) models are more relevant for application. Seven models (Smeed: original, generalized, time-variant, state-variant; and Andreassen: generalized, time-variant, state-variant) were developed and tested for fit with the actual data. Results showed that the per vehicle fatality rate closely resembled Smeed's formulation. Chow-test yielded a significant F-stat, suggesting that the models for four pre-defined time-blocks are structurally different from the 19-year generalized model. The counterclockwise rotation of the log-linear form also suggested lower fatality rates. While the new government policies, reduced vehicle operating speeds, better healthcare, and improved vehicle technology could be the factors, further research is required to understand the reasons for fatality rate reductions. The intercept and gradients of the time-series models showed high stability and varied only slightly in comparison to the 19-year generalized models, thus suggesting that the latter are pragmatic for application. Regional formulations, however, indicate that they may be more relevant for studying trends and tendencies. This research illustrates the robustness of Smeed's law, and provides evidence for time-invariance but state-specificity.

Understanding the cell phone effect on vehicle fatalities: a Bayesian view

This article examines the potential effect of various factors on motor vehicle fatality rates using a rich set of panel data and classical regression analysis combined with Bayesian Extreme Bounds Analysis (EBA), Bayesian Model Averaging (BMA) and Stochastic Search Variable Selection (SSVS) procedures. The variables examined in the models include traditional motor vehicle and socioeconomic factors. In addition, the models address the effects of cell phone usage on such accidents. The use of both classical and Bayesian techniques diminish the model and parameter uncertainties which afflict more conventional modelling methods which rely on only one of the two methods.

Graduated driver license nighttime compliance in U.S. teen drivers involved in fatal motor vehicle crashes

BackgroundExamination of teen driver compliance with graduated driver licensing (GDL) laws could be instrumental in identifying factors associated with persistently high motor vehicle mortality rates. MethodsFatality analysis reporting system (FARS) data from the years 2006 to 2009 were used in this nation-wide cross-sectional study of drivers covered by a state nighttime GDL law (n=3492). A new definition of weekend, based on the school night in relation to the teenage social landscape, redefined Friday night as a weekend night and Sunday night as a weekday/school night and compared it to previous weekend definitions. Multiple logistic regression was used to examine independent effects of demographic, behavioral, environmental, contextual, and other factors on compliance with nighttime GDL laws. All analyses were performed in Stata version 11. ResultsGiven coverage under nighttime GDL laws, drivers aged 15–17 years were non-compliant in 14.9% of the fatal MVCs in which they were involved, and nearly one-fifth (18.8%) of all fatalities aged 15–17 years were associated with non-compliance. Mortality risk was 10% higher using a revised social (school night) versus traditional (Sat–Sun) weekend definitions. In multivariable analysis, drivers non-compliant with nighttime GDL laws were more likely to be drinking (OR=4.97, 3.85–6.40), unbelted (OR=1.58, 1.25–1.99), driving on the weekend (OR=1.82, 1.47–2.24), and killed (OR=1.31, 1.04–1.65). ConclusionGDL non-compliance contributes to teen motor vehicle mortality. Legislative and enforcement efforts targeting non-school night driving, seatbelt nonuse and alcohol have potential to further reduce teen driving mortality.

Using funnel plots in public health surveillance.

BackgroundPublic health surveillance is often concerned with the analysis of health outcomes over small areas. Funnel plots have been proposed as a useful tool for assessing and visualizing surveillance data, but their full utility has not been appreciated (for example, in the incorporation and interpretation of risk factors).MethodsWe investigate a way to simultaneously focus funnel plot analyses on direct policy implications while visually incorporating model fit and the effects of risk factors. Health survey data representing modifiable and nonmodifiable risk factors are used in an analysis of 2007 small area motor vehicle mortality rates in Alberta, Canada.ResultsSmall area variations in motor vehicle mortality in Alberta were well explained by the suite of modifiable and nonmodifiable risk factors. Funnel plots of raw rates and of risk adjusted rates lead to different conclusions; the analysis process highlights opportunities for intervention as risk factors are incorporated into the model. Maps based on funnel plot methods identify areas worthy of further investigation.ConclusionsFunnel plots provide a useful tool to explore small area data and to routinely incorporate covariate relationships in surveillance analyses. The exploratory process has at each step a direct and useful policy-related result. Dealing thoughtfully with statistical overdispersion is a cornerstone to fully understanding funnel plots.

Speed Kills? Not Always: The New York State Thruway Experience

The New York State (NYS) speed limit increased from 55 mph to 65 mph in August 1995. This study examines the change in motor vehicle fatality rates on the NYS thruway and NYS Interstates before and after the speed limit change. We also compare the fatality rates pre- and postincreased speed limit between the NYS thruway and other major NYS roadways, where speed limit remained unchanged at 55 mph. The number of fatalities and vehicle miles traveled (VMT) on individual roadways were extracted from NYS Department of Transportation reports. The data were divided into groups by prespeed limit change, August 1992 to August 1995, and postspeed limit change, August 1995 to August 1998, and roads where the speed limit remained unchanged at 55 mph. Data were also analyzed to assess the effect of variability of speed and general topography on changes in fatality rates on roads where the speed limit was increased. There was a 28.3% decrease in absolute mortality and a 42.6% decrease in mortality adjusted for VMT, on the NYS thruway after the speed limit increase from 55 mph to 65 mph. When compared with roadways, where the speed limit remained unchanged, there was a 52.4% reduction in fatality rates below the predicted rates after the speed limit increase (p = 0.009). On the NYS interstate system, there was a 13.5% decrease in absolute mortality and a 29.2% decrease in mortality adjusted for VMT, after the speed limit increase. The percentage of traffic traveling >10 mph faster than the speed limit dropped from 39% to 8% on roads, where the speed limit was increased from 55 mph to 65 mph. In the NYS interstate system, "flat" roads (elevation <200 m) had a 30.2% reduction in absolute mortality, whereas "mountainous" roads (elevations >200 m) had a 17.6% increase in absolute mortality in response to the speed limit increase (p < 0.001). Motor vehicle speed is a key determinate of the severity of injury in an individual crash; however, speed variance and road topography have also been found to impact the total number of motor vehicle fatalities in the NY State highway system.