Associations of distraction involvement and age with driver injury severities

IntroductionThis paper investigates the associations between the severity of injuries sustained by a driver who is involved in a two-vehicle crash, the existence and type of driver distraction as well as driver's age. Few studies investigated distraction as it relates to injury severity. Moreover, these studies did not consider driver age which is a significant factor related to driving behavior and the ability to respond in a crash situation.MethodsAn ordered logit model was built to predict injury severity sustained by drivers using data from the U.S. National Automotive Sampling System's General Estimates System (2003 to 2008). Various factors (e.g., weather, gender, and speeding) were statistically controlled for, but the main focus was on the interaction of driver age and distraction type.ResultsThe trends observed for young and mid-age drivers were similar. For these age groups, dialing or texting on the cell phone, passengers, and in-vehicle sources resulted in an increase in a likelihood of more severe injuries. Talking on the cell phone had a similar effect for younger drivers but was not significant for mid-age drivers. Inattention and distractions outside the vehicle decreased the odds of severe injuries. For older drivers, the highest odds of severe injuries were observed with dialing or texting on a cell phone, followed by in-vehicle sources and talking on the cell phone. All these sources were associated with an increased likelihood of injury severity. Similar to young and mid-age drivers, distractions outside the vehicle decreased the odds of severe injuries. Other distraction types did not have a significant effect for the older age group.ConclusionsThe results support previous literature and extend our understanding of crash injury severity.Practical applicationsThe findings have implications for policy making and the design of distraction mitigation systems.     

Seatbelt non-use and car crash injury: an interview study

OBJECTIVES: To examine the relationship between seatbelt non-use at the time of a crash, habitual non-use of seatbelts, and car crash injury; and to calculate the population attributable risk for car crash injury due to seatbelt non-use. METHODS: A population-based case control, interview study in Auckland, New Zealand, with 571 injured or killed drivers as cases and 588 population-based controls randomly selected from the driving population. RESULTS: Unbelted drivers had 10 times the risk of involvement in an injury crash compared to belted drivers after adjustment for multiple confounders. Habitual non-users were likely to be unbelted when involved in a crash. The population attributable risk for seatbelt non-use was 13%. CONCLUSIONS: Non-use of seatbelts is very strongly associated with increased injury crash involvement. Even where seatbelt use rates are higher than 90%, there remains a small group of habitual non-users who are at high risk; these drivers may benefit from targeted interventions.     

Analyses of rear-end crashes based on classification tree models

OBJECTIVE: Signalized intersections are accident-prone areas especially for rear-end crashes due to the fact that the diversity of the braking behaviors of drivers increases during the signal change. The objective of this article is to improve knowledge of the relationship between rear-end crashes occurring at signalized intersections and a series of potential traffic risk factors classified by driver characteristics, environments, and vehicle types. METHODS: Based on the 2001 Florida crash database, the classification tree method and Quasi-induced exposure concept were used to perform the statistical analysis. Two binary classification tree models were developed in this study. One was used for the crash comparison between rear-end and non-rear-end to identify those specific trends of the rear-end crashes. The other was constructed for the comparison between striking vehicles/drivers (at-fault) and struck vehicles/drivers (not-at-fault) to find more complex crash pattern associated with the traffic attributes of driver, vehicle, and environment. RESULTS: The modeling results showed that the rear-end crashes are over-presented in the higher speed limits (45-55 mph); the rear-end crash propensity for daytime is apparently larger than nighttime; and the reduction of braking capacity due to wet and slippery road surface conditions would definitely contribute to rear-end crashes, especially at intersections with higher speed limits. The tree model segmented drivers into four homogeneous age groups: < 21 years, 21-31 years, 32-75 years, and > 75 years. The youngest driver group shows the largest crash propensity; in the 21-31 age group, the male drivers are over-involved in rear-end crashes under adverse weather conditions and the 32-75 years drivers driving large size vehicles have a larger crash propensity compared to those driving passenger vehicles. CONCLUSIONS: Combined with the quasi-induced exposure concept, the classification tree method is a proper statistical tool for traffic-safety analysis to investigate crash propensity. Compared to the logistic regression models, tree models have advantages for handling continuous independent variables and easily explaining the complex interaction effect with more than two independent variables. This research recommended that at signalized intersections with higher speed limits, reducing the speed limit to 40 mph efficiently contribute to a lower accident rate. Drivers involved in alcohol use may increase not only rear-end crash risk but also the driver injury severity. Education and enforcement countermeasures should focus on the driver group younger than 21 years. Further studies are suggested to compare crash risk distributions of the driver age for other main crash types to seek corresponding traffic countermeasures.     

Continued trends in older driver crash involvement rates in the United States: Data through 2017–2018

Introduction: With the growing older adult population due to the aging baby-boom cohort, there was concern that increases in fatal motor-vehicle crashes would follow. Yet, previous analyses showed this to be untrue. The purpose of this study was to examine current trends to determine if previous declines have persisted or risen with the recent increase in fatalities nationwide. Methods: Trends among drivers ages 70 and older were compared with drivers 35–54 for U.S. passenger vehicle fatal crash involvements per 100,000 licensed drivers from 1997 to 2018, fatal and all police-reported crash involvements per vehicle miles traveled using the 1995, 2001, 2009, and 2017 National Household Travel Surveys, and driver deaths per 1,000 crashes. Results: Since the mid-1990s, fatal crashes per licensed driver trended downward, with greater declines for drivers ages 70 and older than for middle-aged drivers (43% vs. 21%). Fatal crash rates per 100,000 licensed drivers and police-reported crash rates per mile traveled for drivers ages 70–79 are now less than those for drivers ages 35–54, but their fatal crash rates per mile traveled and risk of dying in a crash remain higher as they drive fewer miles. As the economy improved over the past decade, fatal crash rates increased substantially for middle-aged drivers but decreased or remained stable among older driver age groups. Conclusions: Fatal crash involvements for adults ages 70 and older has recently increased, but they remain down from their 1997 peak, even as the number of licensed older drivers and the miles they drive have increased. Health improvements likely contributed to long-term reductions in fatal crash rates. As older drivers adopt vehicles with improved crashworthiness and safety features, crash survivability will improve. Practical Application: Older adults should feel confident that their independent mobility needs pose less risk than previously expected.     

A neglected risky behavior among children and adolescents: underage driving and injury in New South Wales,Australia

PROBLEM: Among different causes of injury, roads and traffic-related incidents contributed most to all child deaths. The majority of childhood and adolescent traffic-related deaths are young people killed as pedestrians or bicyclists. Underage driving is a particular risky behavior much neglected. This study aimed to describe some characteristics related to motor-vehicle crashes and crash-related injury in which the vehicle was driven by a young person who was under the legal age of obtaining a learner license in New South Wales, Australia. METHODS: Data used in this study were made available from the Roads and Traffic Authority of NSW for the period between 1996 and 2000. Crash information was collected and reported by NSW police at the scene of these motor-vehicle crash incidents. RESULTS: There were 526 crashes involving an underage driver recorded within the study period. The majority (79.5%) of these underage drivers were males with slightly more than half (58.0%) aged 15 years, and nearly 30% aged 14 years. Among these, 83.6% involved the driver of the vehicle being killed or injured. Among the injured or killed passengers, 128 (73.6%) were nonadult passengers under the age of 18 years. Seventy of these crashes occurred while the car was in pursuit by police. The adjusted relative risk of injury to at least one occupant in the vehicle should a crash occur for female underage drivers was two times (OR=2.01, 95% CI=1.27-3.20) as compared to male underage drivers. DISCUSSION: Underage driving poses a serious problem in terms of crash outcomes. Experimental driving and late-night outings for adolescents should be discouraged. Well-designed studies are required to further investigate the relationship between underage driving and on road risk-taking behavior among licensed adolescents. IMPACT ON INDUSTRY: Data obtained from this study indicate that adults, particularly parents, should discourage underage adolescents from experimenting driving and should actively cultivate a positive attitude toward driving.     

Passenger distractions among adolescent drivers

PROBLEM: Adolescents who drive with peers are known to have a higher risk of crashes. While passengers may distract drivers, little is known about the circumstances of these distractions among teen drivers. METHOD: This study used survey data on driving among 2,144 California high school seniors to examine distractions caused by passengers. RESULTS: Overall, 38.4% of youths who drove reported having been distracted by a passenger. Distractions were more commonly reported among girls and students attending moderate- to high-income schools. Talking or yelling was the most commonly reported type of distraction. About 7.5% of distractions reported were deliberate, such as hitting or tickling the driver or attempting to use the vehicle's controls. Driving after alcohol use and having had a crash as a driver were both significant predictors of reporting passenger-related distraction. CONCLUSION: Adolescents often experience distractions related to passengers, and in some cases these distractions are intentional. IMPACT ON INDUSTRY: These results provide information about teenage drivers who are distracted by passenger behaviors. In some cases, passengers attempted to use vehicle controls; however, it seems unlikely that this behavior is common enough to warrant redesign of controls to make them less accessible to passengers.     

Understanding driver distractions in fatal crashes: An exploratory empirical analysis

Introduction: Driver distraction has become a significant problem in transportation safety. As more portable wireless devices and driver assistance and entertainment systems become available to drivers, the sources of distraction are increasing. Method: Based on the results of different studies in the literature review, this paper categorizes different distraction enablers into six subcategories according to their fundamental characteristics and how they would affect a driver's likelihood of engaging in non-driving related activities. The review also discusses the characteristics and influence of external and internal distractions. The objective of this study is to examine the effect of different distraction sources in fatal crashes with the consideration of a driver's age and sex. Tukey test, chi-square test of independence, Nemenyi post-hoc test, and Marascuilo procedure have been used to investigate the top distraction sources, the trend of distraction-affected fatal crashes, the effect of different distractions on drives in different age groups, and their influence on female and male drivers. Results: It was found that inner cognitive inferences accounted for the greatest proportion of driver engagement in distractions. Young drivers show a larger probability of being distracted by in-vehicle technology-related devices/objects. Within the group of young drivers, female drivers showed a higher probability than their male counterparts of engaging in distracted driving caused by in-vehicle technology-related devices. Among six subcategories of distractions, drivers older than 80 years old were found to be most likely affected by inner cognitive interferences.     

Driver aging and its effect on male and female single-vehicle accident injuries: some additional evidence

INTRODUCTION: This study explores the differences in injury severity between male and female drivers, and across the different age groups, in single-vehicle accidents involving passenger cars. METHOD: Given the occurrence of an accident, separate male and female multinomial logit models of injury severity (with possible outcomes of no injury, injury, and fatality) were estimated for young (ages 16 to 24), middle-aged (ages 25 to 64), and older (ages 65 and older) drivers. RESULTS: The estimation results show statistically significant differences in the factors that determine injury-severity levels between male and female drivers and among the different driver age groups. CONCLUSIONS: We discuss a number of plausible explanations for the observed age/gender differences and provide suggestions for future work on the subject. IMPACT ON INDUSTRY: A better understanding of age and gender differences can lead to improvements in vehicle and highway design to minimize driver injury severity. This paper provides some new evidence to help unravel this complex problem.     

First year as a licensed car driver: Gender differences in crash experience

Objective: To explore the crash experience and crash consequences of newly licensed male and female drivers aged 18–29 years.Methodology: A national register-based population cohort of persons born between 1970 and 1972 was followed for the period 1988–2000 on the basis of crash data in Swedish police records. The analyses focused on two crash categories regardless of consequences: single car (SC) and car-to-motor vehicle (CMV).Results: Crash incidence for men was nearly double that of women in all age groups in both crash categories. Age had a protective effect for both sexes, especially for SC crashes. Males, but not females, showed a lag in time from driving license issue date to first crash for SC crashes, which increased with age of obtaining a license. Men’s crash fatality rate was five times higher than that of women for SC crashes (32.2 and 6.1 per 1000, respectively), but the rate was comparable for CMV crashes (16.1 and 15.7, respectively). The crash morbidity rate was 25–30% higher for male drivers in both crash categories.Conclusions: Both young age and male sex emerge as important determinants of crash risk and crash consequences among young Swedish drivers.     

Effect of vehicle and crash factors on older occupants

PROBLEM: The expected substantial increase in people aged 65 or older is important for those concerned about transportation injuries. However, much of the previous research concentrates on older drivers and overlooks the fact that vehicle and crash factors may provide significant explanations of older occupant injury rates. METHOD: Differences across age groups are explored using two nationwide travel surveys, crash involvement, fatalities, and injuries from crash databases and an ordered probit model of injury severity. RESULTS AND DISCUSSION: Two noticeable differences that help explain injury risk are that older people are more likely to travel in passenger cars than younger people who frequently use light trucks, and that seriously injured older occupants are more likely to be involved in side-impact crashes than their younger counterparts. IMPACT: Increased attention to vehicle engagement in side-impact crashes and to vehicle technologies that can help drivers avoid side collisions would be particularly helpful for older occupants.     

Crash risk by driver age,gender, and time of day using a new exposure methodology

Introduction: Concerns have been raised that the nonlinear relation between crashes and travel exposure invalidates the conventional use of crash rates to control for exposure. A new metric of exposure that bears a linear association to crashes was used as basis for calculating unbiased crash risks. This study compared the two methods – conventional crash rates and new adjusted crash risk – for assessing the effect of driver age, gender, and time of day on the risk of crash involvement and crash fatality. Method: We used police reports of single-car and multi-car crashes with fatal and nonfatal driver injuries that occurred during 2002–2012 in Great Britain. Results: Conventional crash rates were highest in the youngest age group and declined steeply until age 60–69 years. The adjusted crash risk instead peaked at age 21–29 years and reduced gradually with age. The risk of nighttime driving, especially among teenage drivers, was much smaller when based on adjusted crash risks. Finally, the adjusted fatality risk incurred by elderly drivers remained constant across time of day, suggesting that their risk of sustaining a fatal injury due to a crash is more attributable to excess fragility than to crash seriousness. Conclusions: Our findings demonstrate a biasing effect of low travel exposure on conventional crash rates. This implies that conventional methods do not yield meaningful comparisons of crash risk between driver groups and driving conditions of varying exposure to risk. The excess crash rates typically associated with teenage and elderly drivers as well as nighttime driving are attributed in part to overestimation of risk at low travel exposure. Practical Applications: Greater attention should be directed toward crash involvement among drivers in their 20s and 30s as well as younger drivers. Countermeasures should focus on the role of physical vulnerability in fatality risk of elderly drivers.     

Characteristics of vehicles driven by teens and adults killed in crashes, 2013–2017

Introduction: Teen drivers experience higher crash risk than their experienced adult counterparts. Legislative and community outreach methods have attempted to reduce this risk; results have been mixed. The increasing presence of vehicle safety features across the fleet has driven fatality numbers down in the past decades, but the disparity between young drivers and others remains. Method: We merged Fatality Analysis Reporting System (FARS) data on fatal crashes with vehicle characteristic data from the Highway Loss Data Institute (HLDI). The analysis compared the vehicle type, size, age, and the presence of select safety features in vehicles driven by teens (ages 15–17 years) and adult drivers (ages 35–50 years) who were killed in crashes from 2013 to 2017. Results were compared with a similar analysis conducted on data from 2007 to 2012. Results: Teen drivers were more likely than their adult counterparts to be killed while driving older, smaller vehicles that were less likely to have the option to be equipped with side airbags. Discussion: Teenage drivers remain more likely to be killed while driving older, smaller vehicles than adult drivers. Parents and guardians are mainly responsible for teen vehicle choice, and should keep vehicle size, weight, and safety features in mind when placing their teen in a vehicle. Practical Application: These findings can help guide safer vehicle choice for new teen drivers.     

Teenage driver crash incidence and factors influencing crash injury by rurality

BackgroundPrevious research has identified teenage drivers as having an increased risk for motor-vehicle crash injury compared with older drivers, and rural roads as having increased crash severity compared with urban roads. Few studies have examined incidence and characteristics of teen driver-involved crashes on rural and urban roads.MethodsAll crashes involving a driver aged 10 through 18 were identified from the Iowa Department of Transportation crash data from 2002 through 2008. Rates of overall crashes and fatal or severe injury crashes were calculated for urban, suburban, rural, and remote rural areas. The distribution of driver and crash characteristics were compared between rural and urban crashes. Logistic regression was used to identify driver and crash characteristics associated with increased odds of fatal or severe injury among urban and rural crashes.ResultsFor younger teen drivers (age 10 through 15), overall crash rates were higher for more rural areas, although for older teen drivers (age 16 through 18) the overall crash rates were lower for rural areas. Rural teen crashes were nearly five times more likely to lead to a fatal or severe injury crash than urban teen crashes. Rural crashes were more likely to involve single vehicles, be late at night, involve a failure to yield the right-of-way and crossing the center divider.ConclusionsIntervention programs to increase safe teen driving in rural areas need to address specific risk factors associated with rural roadways.Impact on IndustryTeen crashes cause lost work time for teen workers as well as their parents. Industries such as safety, health care, and insurance have a vested interest in enhanced vehicle safety, and these efforts should address risks and injury differentials in urban and rural roadways.     

Side impact crashes--factors affecting incidence and severity: review of the literature

Many traffic crashes are side impact collisions resulting in significant death and injury. A review was conducted of the evidence of driver, road, and vehicle characteristics affecting either the risk of occurrence or the severity of injury in such crashes for papers published from 1996 to early 2003. For drivers, evidence was found of increased crash risk or injury severity only for age and age-related medical conditions (e.g., dementia). Traffic roundabouts and other traffic control devices--stop signs, traffic lights, and so on--had mixed results; traffic controls were better than no controls, but their effectiveness varied with circumstance. Most vehicle characteristics have had little or no effect on crash occurrence. Antilock braking systems (ABS) in the striking vehicle had been anticipated to reduce the risk of crashes, but so far have demonstrated little effect. The primary emphasis in vehicle design has been on protective devices to reduce the severity of injury. Disparity in the size of the two vehicles, especially when the struck vehicle is smaller and lighter, is almost a consistent risk factor for occupant injury. The occupants of light trucks, however, when struck by passengers cars on the opposite side, were at higher risk of injury. Wearing seat belts had a consistently protective effect; airbags did not, but there were few studies, and no field studies, of lateral airbags found. Of all the characteristics examined, vehicle design, including occupant restraints, is the most easily modified in the short term, although road design, traffic control, and the monitoring of older drivers may also prove effective in reducing side impact crashes in the longer term.     

An application of a conditional logistic regression to study the effects of safety belts, principal impact points, and car weights on drivers' fatalities

In addition to experimental trials in automotive factories, there is a fundamental need to monitor real people involved in real motor vehicle collisions to determine the impact of automotive design characteristics on injury mortality. To aid in designing future safety features for drivers' seats, data from the Fatal Accident Reporting System (FARS) were used to assess the effects of safety belts, directions of crash impacts, age, sex, and car weights on motor vehicle injury fatalities. Furthermore, because the FARS includes only accidents in which there was at least one fatality, this paper introduces a multivariate approach — a logistic regression conditioned on each accident —to avoid the sampling biases inherent in the FARS. The resulting model is used to quantify the relations among the safety belts, the directions of crash impacts, and vehicle weights and their effects on fatalities. Recause the proposed approach allows researchers to study many important variables simultaneously and eliminates the biases resulting from many possible confounders, the estimates presented in this paper are considered to be more precise and more firmly established than earlier estimates. The new approach to analyzing the FARS data will also be useful for investigating the effects of other risk factors or automotive characteristics on crash fatalities.     

Comparison of mid-block and intersection-related left turn collisions

OBJECTIVES: To evaluate the factors that might influence an occupant's injury severity during a left turn movement. METHODS: We used the National Automotive Sampling System Crashworthiness Data System (1995-2005) to compare crash characteristics and injury outcome between intersection and midblock left turn collisions. RESULTS: A total of 7,396 collisions were evaluated. Traffic control devices were present in 82% of intersection and 10% of mid-block collisions. After adjustment for potential confounding variables, drivers' injury severity was not significantly associated with the crash location. However, front seat passengers in mid-block collisions had 72% higher odds of experiencing an injury with injury severity score > or =9 (odds ratio: 1.72, 95% confidence interval: 1.09-2.69). Our analysis did not show that drivers or passengers in larger vehicles, e.g., sport utility vehicles and mini-vans, were at lower risk of more severe injuries in comparison to the car occupants in sedans. CONCLUSION: We found that in comparison to intersection-related left turn collisions, mid-block crashes are associated with more severe injuries for front seat passengers. Furthermore, size of the turning vehicle was not significantly associated with injury severity for drivers or front seat passengers.     

The safety implications of vehicle seat adjustments

INTRODUCTION: The goal of this study was to gather information on the preferred front seat position of vehicle occupants and to determine the impact of variation in seat position on safety during crashes. METHOD: The study evaluated the relationship between seat position and occupant size using the chi-square test and compared the risk of severe injury for small females and large males with regard to forward and rearward seat position using logistic regression. RESULTS: While smaller drivers sat closer to the steering wheel than larger drivers, front passengers of all sizes used similar seat positions. Additionally, the risk of injury was higher for small, unbelted females in rearward seat positions and large males (belted and unbelted) in forward seat positions. CONCLUSIONS: Occupants who adjust their seats to positions that are not consistent with required federal tests are at a greater risk for severe injury in a crash.     

Views of US drivers about driving safety

Problem: To assess how drivers view dangers on the highway, what motivates them to drive safely, how they say they reduce their crash and injury risk, and how they rate their own driving skills. Results: Most drivers rated their skills as better than average. The biggest motivating factor for safe driving was concern for safety of others in their vehicle, followed by negative outcomes such as being in a crash, increased insurance costs, and fines. The greatest threats to their safety were thought to be other drivers' actions that increase crash risk such as alcohol impairment or running red lights. In terms of reducing crashes and injuries, drivers tended to focus on actions they could take such as driving defensively or using seat belts. There was less recognition of the role of vehicles and vehicle features in crash or injury prevention. Impact on research, practice, and policy: Knowing how drivers view themselves and others, their concerns, and their motivations and techniques for staying out of trouble on the roads provides insight into the difficulty of changing driving practices.     

Factors related to seat belt use among fatally injured teenage drivers

PROBLEM: In the United States, teenage drivers have a higher crash risk and lower observed seat belt use than other age groups. METHOD: Seat belt use was examined for teenage (16-19 years) drivers who were fatally injured in traffic crashes occurring in the United States during the years 1995-2000. Vehicle, driver, and crash factors potentially related to belt use were examined. State differences in belt use rates among fatally injured teenage drivers were related to states' observed belt use rates for all ages and other state-level variables. RESULTS: During 1995-2000, mean belt use was 36% among fatally injured teenage drivers and 23% among fatally injured teenage passengers. One of the strongest predictors of higher belt use for both drivers and passengers was whether the crash occurred in a state with a primary seat belt law. Belt use rates for 1995-2000 for fatally injured teenage drivers ranged from 20% or less in six states to more than 60% in two states. States with the highest use rates were those with strong primary belt use laws and those with high rates of observed belt use for all ages. Lower belt use among fatally injured teenage drivers was associated with increasing age; male drivers; drivers of SUVs, vans, or pickup trucks rather than cars; older vehicles; crashes occurring late at night; crashes occurring on rural roadways; single vehicle crashes; and drivers with BACs of 0.10 or higher. Teenage driver belt use declined as the number of teenage passengers increased, but increased in the presence of at least one passenger 30 years or older. IMPACT ON TRAFFIC SAFETY: It is suggested that to increase teenage belt use, states should enact strong primary belt use laws and mount highly publicized efforts to enforce these laws. Graduated driver licensing systems should incorporate strong provisions that require seat belt use by teenage drivers and passengers.