Driver Age Groups Research Articles

Effect of Passenger Age and Gender on Fatal Crash Risks of Young Drivers

The effect of passenger age and gender on young driver fatal crash risk was studied with police-reported crash data in Louisiana from 1999 to 2004. Young drivers were divided into three age groups—16, 17, and 18 to 20 years of age—by gender. Passengers were grouped into 15 to 17 and 18 to 20 years of age by gender. A series of analyses of young drivers and young passengers was conducted to study their risks of being involved in fatal crashes. Relative risks and crash rates were used to measure crash risk. The analyses followed step-by-step disaggregation of driver and passenger characteristics, including the number of passengers, passenger age, and passenger age and gender for each driver age and gender group. It was found that young drivers are negatively affected by young passengers, especially from their own peer age groups. However, the presence of adult passengers reduces their fatal crash risks. Sixteen-and 17-year-old drivers have similar fatal risk patterns that are much higher than and different from those of 18- to 20-year-old drivers; 16- and 17-year-old drivers are associated with the highest fatal crash risks when driving with their same gender and age group passengers, with male-to-male driver–passenger combination having higher fatal crash risk than female-to-female driver–passenger combination. As age progresses, fatal crash risk differences between male and female young drivers also increase.

Preface: Driving and the Promotion of Safe Mobility in Older Populations

IN the present issue of the Journal, we present a fine article by Richard Marottoli and colleagues reporting the results of a randomized trial of a multicomponent education program to improve driving knowledge and performance of older at-risk drivers, together with an excellent guest editorial by William Satariano. As noted by both, safe driving is an ascendant public policy issue in an aging society built around automobiles. Professor Satariano mentions several ways in which safe driving might be achieved. The public—and public policy— are likely to understand ‘‘save driving’’ in terms of agespecific crash rates and widely-reported, egregious incidents involving older drivers, rather than the more esoteric terms of crashes per miles driven. Interventions affecting safe driving fall into two categories: those that result in curtailment in driving in the at-risk (either self-initiated or via the kinds of state actions Satariano describes, the effect of which may reduce the opportunity for crashes), and those that improve the driving performance of the at-risk older drivers. Marottoli’s educational program is of the latter sort. This well-designed trial demonstrated significant results at 8 weeks, specifically, improved road-test performance and improved knowledge test scores. Based on unpublished data from a prior study, he estimates that the observed improvement would translate into a 9.5% decrease in crash risk, surely an important reduction if true and sustained. A problem for programs attempting to improve safe driving of older drivers through knowledge, skills, and performance enhancements is the fact that they may, over time, encourage older drivers to drive more frequently, longer distances, or longer before quitting or reducing the activity. The extent, then, to which performance enhancement impacts crash rates per driver age-group per time-unit seems to be an open question, as suggested by Marottoli’s review of the sparse literature. Ultimately, there will be a special burden on programs aiming to improve driving skills of at-risk older drivers to demonstrate not only proximal knowledge and road-test gains, but effects of training on driving frequency, behavior, and crashes ‘‘down the road.’’ There is an interesting parallel between this kind of intervention and physical activity and related programs targeted to older people at risk of falls, which result not in fewer falls but more walking. The special problem of driving is that the consequences of crashes impact not only on the older driver, but on other drivers, passengers, and pedestrians. We encourage readers to write the Journal offering comments on this and related research, and suggestions concerning next steps.

Factors Leading to Older Drivers' Intersection Crashes

Objectives. Older drivers are overinvolved in intersection crashes compared with younger drivers, but the reasons are not clearly understood. The purpose of the present study was to identify the factors that lead to older drivers' intersection crashes. Method. Study participants were composed of two groups of older drivers—ages 70–79 (n = 78) and 80 and older (n = 76)—and a comparison group of drivers ages 35–54 (n = 73); all were at fault in intersection crashes involving nonfatal injuries. Police crash reports, telephone interviews with at-fault drivers, and photographs of intersections were used to determine the kinds of driver actions and errors that led to the intersection crashes. Results. Drivers 80 and older had fewer rear-end crashes than drivers ages 35–54 and 70–79, and both groups of older drivers had fewer ran-off-road crashes than drivers ages 35–54. Crashes where drivers failed to yield the right-of-way increased with age and occurred mostly at stop sign–controlled intersections, generally when drivers were turning left. The reasons for failure-to-yield crashes tended to vary by age. Compared with drivers ages 35–54 and 80 and older, drivers ages 70–79 made more evaluation errors—seeing another vehicle but misjudging whether there was adequate time to proceed. In contrast, drivers 80 and older predominantly failed to see or detect the other vehicle. Drivers ages 35–54 also tended to make search errors, but theirs were due more often to distraction. Conclusions. Factors leading to intersection crashes vary with age, even between two age groups of older drivers. Because the number of older drivers is projected to increase, it is important to identify ways to reduce the frequency and severity of their intersection crashes. Roundabouts and protected left turn lanes at signalized intersections may help to reduce failure-to-yield crashes at intersections, especially among older drivers. Crash avoidance systems may help to reduce crashes for drivers of all ages, but most systems have not been thoroughly investigated using real-world crash data.

Driving violations observed: An Australian study

This study analyses 2765 cases of driving behaviours in three Australian states – New South Wales, Queensland and Victoria. Data were gathered from in-car coordinated video and audio recording sequences in free-flowing traffic along two-, three- and four-lane highways with varying speed limits on all days of the week in daylight and fine weather conditions. Explanatory variables included driver age group and gender, passenger characteristics and vehicle age and type. Response variables included driving violations and other driving behaviours, including lane use, speeding, close following (tailgating), driver's hands position and mobile phone use. Data were analysed qualitatively and quantitatively. By focusing upon vehicle and driver characteristics, and their impact on driving behaviours, including identified violations, this study explores some implications both for future research and for traffic policy makers.

Travel patterns of three distinct driver age groups in Greece

Within this research the travel patterns of passenger car drivers are investigated in relation to their age, as recorded from a national travel survey conducted in Greece. For the needs of this research drivers are classified into three mutually exclusive age groups: young (18–24), adult (25–64) and elderly (65+). The mobility of these three driver groups—expressed in terms of average annual distance driven—is then investigated with respect to parameters involving driver characteristics (experience, gender), vehicle characteristics (engine size) and the nature of the trip (time of trip and road type). Several patterns are analysed, and the dependence of the various travel patterns on driver age is tested through analysis of variance (ANOVA), mainly by the use of the Welch test. The results show that driver experience is not an influencing factor for driver mobility, whereas driver gender and vehicle characteristics, such as engine size, are. Furthermore, the results illustrate dependences between driver age and driving at night and during the weekends, highlighting the relationship between driver age and trip purpose. The distribution of mobility across the different road types does not reveal any interactions with driver age; however, specific trends are detected when distance driven is also segregated into weekday and weekend categories, indicating a relationship between driver age and mobility in relation to type of day.

Driver behaviour, dilemma zone and safety effects at urban signalised intersections in Greece

Driving behaviour at signalised intersections is one of the main factors contributing to the safety level of such entities. This behaviour, with respect to yellow signal obedience or violation, is examined at a signalised intersection in Thessaloniki, Greece. The data, collected for the study purposes, include vehicles’ speeds and distance from stop line when exposed to yellow light, gender and age group of drivers as well as reaction of Platoon leaders and first followers. Drivers were grouped into three categories, namely conservative, normal and aggressive, according to their behaviour at the intersection, the existence of a dilemma or option zone and their initial approaching speed. A binary choice model was also developed relating the probability of stopping at the STOP line or crossing it as a function of approach speed, distance from intersection, gender, age group and the existence or not of a dilemma zone. The findings of this research indicate that a large percentage of drivers facing the yellow signal are caught in a dilemma zone due to high approaching speeds and exercise an aggressive behaviour. The distribution of drivers into the three categories changes with differing assumptions pertaining to the factors affecting the calculation of safe stopping distance and critical crossing distance as well as speed thresholds for determining a priori aggressive behaviour. The research concludes that aggressive drivers represent a high percentage of all drivers and measures towards improving driving behaviour and/or reducing vehicles’ speeds are required.

Fragility and crash over-representation among older drivers in Western Australia

This study assessed age-related and gender differences in the relative contribution of fragility and crash over-representation to serious injuries per crash-involved driver in Western Australia. Police-reported crashes for the period 1998–2003 were extracted from the Western Australian Road Injury Database. For each passenger vehicle driver age and gender group, serious injuries per crash-involved driver and driver involvements in crashes per 100 million vehicle-kilometre travelled (VKT) were calculated as the respective measure of fragility and crash over-representation. Results from the decomposition method of analysis showed that older drivers over the age of 70 sustained serious injury rates more than twice as high as those of the 30–59-year-old drivers. Fragility increased with age, contributing between 47% and 95% for drivers above 65 years, but crash over-representation was the dominant factor for male drivers above 80 years. In contrast, fragility contributed little to the excess injury risk of younger drivers under the age of 30. The importance of fragility as a contributing factor to the inflated serious injury risk per vehicle-kilometre travelled for older drivers suggested that road safety initiatives should be directed towards the protection of vehicle occupants as well as screening for their driving ability.

Impact of Georgia’s Teenage and Adult Driver Responsibility Act

In 1997, the Georgia General Assembly enacted the Teenage and Adult Drivers Responsibility Act (TADRA), a comprehensive legislative package that attempted to reduce fatal crashes of teenaged drivers by introducing graduated driver's licensing, "zero tolerance" of underage impaired drivers, and automatic license revocation for speeding greater than 25 miles per hour over the posted limit and other dangerous driving behaviors. To determine whether TADRA reduced teen driving fatalities, we examine fatal crash rates involving various age groups before versus after the law was enacted. Data from the Fatal Accident Reporting System were used to calculate annualized fatal crash rates of various age groups of drivers during an 11-year interval 5 1/2 years before TADRA was enacted and 5 1/2 years afterwards. To identify potential historical effects, Georgia's experience was compared to that of Alabama, South Carolina, and Tennessee, states that did not adopt equally comprehensive legislation during the study period. During the preenactment period, 317 Georgia drivers aged 16 were involved in a fatal crash (57/100,000 person-years) compared to 230 in the postenactment period (36/100,000 person-years; risk ratio [RR] 0.63; 95% confidence interval 0.53 to 0.75). Speed-related fatal crashes were cut by 42%, and alcohol-related fatal crashes decreased nearly 60%, without displacing fatal crashes to older age groups. These reductions greatly exceeded those noted in 2 of 3 comparison states and the nation overall. TADRA markedly reduced fatal crash rates among 16-year-old Georgia drivers. Fatal crashes were not displaced to older age groups.

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.

Driver distraction: The effects of concurrent in-vehicle tasks, road environment complexity and age on driving performance

This paper presents the findings of a simulator study that examined the effects of distraction upon driving performance for drivers in three age groups. There were two in-vehicle distracter tasks: operating the vehicle entertainment system and conducting a simulated hands-free mobile phone conversation. The effect of visual clutter was examined by requiring participants to drive in simple and complex road environments. Overall measures of driving performance were collected, together with responses to roadway hazards and subjective measures of driver perceived workload. The two in-vehicle distraction tasks degraded overall driving performance, degraded responses to hazards and increased subjective workload. The performance decrements that occurred as a result of in-vehicle distraction were observed in both the simple and complex highway environments and for drivers in different age groups. One key difference was that older drivers traveled at lower mean speeds in the complex highway environment compared with younger drivers. The conclusions of the research are that both in-vehicle tasks impaired several aspects of driving performance, with the entertainment system distracter having the greatest negative impact on performance, and that these findings were relatively stable across different driver age groups and different environmental complexities.

Graduated driver licensing: the New Zealand experience

In New Zealand, on 1 August 1987, a three-stage graduated driver licensing (GDL) system that applied to all new drivers aged 15–24 years was introduced. The essential elements of GDL were a 6-month learner license (supervised driving) and an 18-month restricted license stage (with restrictions on night driving and carrying passengers). A blood alcohol limit of 0.03 mg% applied at both stages. Evaluation studies: Early studies indicated that young people were reasonably accepting of the restrictions, with the passenger restriction being the least acceptable. Problems of compliance with the restricted license driving restrictions were reported. Evaluations of the impact of the graduated driver licensing (GDL) on serious traffic-related injury showed that up until 1991–1992, an 8% reduction could be attributed to GDL. At this time, it was considered that reduced exposure was the main reason for this reduction. However, the number of fatalities and hospital admissions among young people continued to decline, as did the population rate and the rate per number of licensed drivers among the young driver age group. A further evaluation study showed that drivers with a restricted license had a smaller proportion of crashes at night, and with passengers, compared with drivers licensed before GDL. Impact of GDL: These results suggested that GDL restrictions had contributed to the reduction in crashes among young people and that it was not simply a case of reduced exposure to risk. An update of the most recent crash statistics indicated that, compared with older age groups, the fatal and serious injury crash rate among young people has remained substantially below the pre-GDL level. This suggests that the impact of GDL has not diminished over time.

DRIVER AGE DIFFERENCES IN DAY AND NIGHT GAP ACCEPTANCE CAPABILITIES

Performance of Two-way Stop-controlled (TWSC) intersections is greatly affected by the gap acceptance capabilities of drivers. However, there have been no detailed studies conducted regarding driver age differences in gap acceptance capabilities under different light conditions. Therefore, this study was conducted to fill the lack of information in that area, by considering three driver age groups (old, middle, and young), two maneuvers (left-turn, and through), and two light conditions (daytime, and nighttime). Field observations were made at several TWSC intersections and data were collected at these sites regarding available and accepted gaps on the major street and age group of minor street drivers, both during daytime and nighttime. Statistical analysis conducted in this study with a 5% level of significance revealed that there were significant differences in gap acceptance capabilities among the three driver age groups under both light conditions. Only older drivers indicated statistically different gap acceptance capabilities depending on the light condition, where they illustrated longer critical gap values during nighttime.

Analysis of Severity of Young Driver Crashes: Sequential Binary Logistic Regression Modeling

Young drivers have the highest fatality involvement rates of any driver age group within the United States driving population. They also experience a higher percentage of single-vehicle crashes compared with others. When looking at the methods of improving this alarming death rate of young drivers, it is important to identify the determinants of higher crash and injury severity. With that intention, the study developed, using the Florida Traffic Crash Database, a set of sequential binary logistic regression models to predict the crash severity outcome of single-vehicle fixed-object crashes involving young drivers. Models were organized from the lowest severity level to the highest and vice versa to examine the reliability of the selection process, but it was found that there was no considerable impact based on this selection. The developed models were validated and the accuracy was tested by using crash data that were not utilized in the model development, and the results were found to be satisfactory. Factors influential in making a crash severity difference to young drivers were then identified through the models. Factors such as influence of alcohol or drugs, ejection in the crash, point of impact, rural crash locations, existence of curve or grade at the crash location, and speed of the vehicle significantly increased the probability of having a more severe crash. Restraint device usage and being a male clearly reduced the tendency of high severity, and some other variables, such as weather condition, residence location, and physical condition, were not important at all.

Monoataxia of upper extremity in motor cortical infarction

<h3>Abstract</h3> <h3>Objective</h3> investigate the impact of a road-safety program on adolescent willingness to engage in risky behaviour as probationary drivers, adjusted for covariates of interest. <h3>Method</h3> <i>b</i>streetsmart is a road-safety program delivered to around 25,000 adolescent students annually in New South Wales. Using a smart phone-based app, student and teacher participation incentives, students were surveyed before and after program attendance. Mixed methods linear regression analysed pre-post modified Behaviour of Young Novice Driver (BYNDS_M) scores. <h3>Results</h3> 2360 and 1260 students completed pre- and post-event surveys respectively. Post-event BYNDS_M scores were around 3 points lower than pre-event scores (−2.99, 95%CI - 3.418 to -2.466), indicating reduced intention to engage in risky driving behaviours. Covariates associated with higher stated intentions of risky driving were exposure to risky driving as a passenger (1.21, 95% CI 0.622-2.011), identifying as non-binary gender (20.8, 95% CI 8.795 to 40.852), adjusting for other predictors. <h3>Conclusions</h3> Trauma-informed, reality-based injury prevention programs are effective in changing short term stated intentions to engage in risky driving, among a pre-independent driving student population. The adolescent novice driver age group is historically challenging to engage, and injury prevention action must be multi-pronged to address the many factors influencing their behaviour. <h3>What is already known on this topic</h3> Road traffic injuries are the leading cause of death for adolescents in most developed countries globally. Injury prevention action must be multi-pronged to address the many factors influencing their behaviour <h3>What this study adds</h3> The bstreetsmart injury prevention intervention which incorporates trauma informed, CBT influence and reality-based road safety information to around 25,000 students annually, showed significant short-term impact on the stated willingness of the study population to engage in risky driving behaviour when obtaining their probationary licence. Adolescents are strongly influenced by examples of risky road behaviours among their closest adult drivers. <h3>How this study might affect research, practice, or policy</h3> Interventions such as bstreetsmart hold a positive place in the multi-pronged approach needed to address the difficult issue of novice drivers.

Transport Mobility for Children and Adolescents with Cerebral Palsy (CP)

Background: The transport mobility of children and adolescents with cerebral palsy (CP) is of vital interest for the individual, as well as for society. Enhanced transport mobility can be related to improved functional health status and a higher degree of autonomy, which in turn may reduce the demand for societal support. UN Resolution 48/96, together with Swedish legislation and ''Vision Zero'' have in different ways established that the transport system must be designed to meet also the needs of children and adolescents with disabilities. Hence, it is necessary to identify and eliminate obstacles hindering children and adolescents with CP from using public transport and other means of transport, such as their own cars, at the same level as other members of society. However, in the case of children and adolescents with CP, the transport situation and the learner driver's educational situation have so far been largely unknown. Aim: The general aim of the thesis was to describe and analyse, from a legislative and a public health perspective, the transport mobility situation for children and adolescents with CP. Furthermore, the general aim was to identify obstacles for the target group to use public transport and other means of transportation, at the same level as other members of the society, and to suggest improvements that will remove the identified obstacles. Material and methods: Several different data collection methods were used. Data, concerning travel habits and parents' perceived risks regarding transportation, were taken from a postal questionnaire addressed to parents of children and adolescents with CP. In order to estimate the numbers of potential learner drivers with CP in each age group in Sweden, a literature review was conducted, based on Swedish material. Furthermore, logbooks for learner drivers with CP were analysed retrospectively, in order to identify procedures, problems and key tasks in their driver education. Visual search strategies for learner drivers with CP were analysed, utilizing an eye tracker, and an attempt was made to introduce a screening tool for predicting the outcome of driver education. Results: Children and adolescents with CP were found to be transported under unsafe conditions, causing worry among their parents. When transporting children in the family vehicle, the parents were exposed to a very heavy burden, which increased their worry. The prevalence of potential learner drivers with CP who were in need of highly specialised driver education, including individually adapted driver training vehicles, was estimated to be 0.15 per 1,000 of a population-based age group of learner drivers in Sweden. Complex procedures, structural problems and financial obstacles made it difficult for adolescents with CP to obtain a driving licence and an adapted vehicle. The total duration of the driving tuition given by a driving instructor was found to be almost nine times higher for learner drivers with CP than for non-disabled learner drivers. Visual search strategies among learner drivers with CP were found to be less flexible than among other learner drivers. This fact indicated a need for better methods of teaching such strategies to this group as an integral component of their driver education. The validity of the motor-free visual perceptual test, TVPS-UL, for predicting the outcome of driver education for learner drivers, was found to be low. In order to find a reliable and valid screening tool for this purpose, future studies should focus on cross-validation of visual perceptual and dual task performance tests for different types of independent variables, such as obtaining a driving licence or not, accident involvement and driving ability. Conclusion: The transport system was found, from a legislative and public health perspective, to be unsuitable to meet the needs of children and adolescents with CP. Suggestions for improving transport mobility for children and adolescents with CP are provided. Several of these suggestions are practical, concrete and contextual for Swedish conditions, and some of them necessitate future research. However, a number of these suggestions are also applicable in an international context.

THE DIFFERENCES OF DRIVING BEHAVIOR AMONG DIFFERENT DRIVER AGE GROUPS AT SIGNALIZED INTERSECTIONS

Over the past few years the population of older drivers has substantially increased across the United States. Older drivers are a group of special interest because of their potential age-related deficiencies. It is essential to understand their driving behavior and adjust the conditions of roadway systems according to their requirements. Likewise, driving behavior of older drivers needs to be considered in order to adequately estimate capacities at intersections. In the past few years, research projects were performed by the University of South Florida to analyze the differences of driving behavior among different driver age groups. Typically, the driving behavior of older drivers was evaluated by analyzing their start-up lost time and saturation headway at signalized intersections as compared to young and mid-age driver groups. Research results were based on data collected from signalized intersections with different land-use types. These intersections are located in west and central Florida where the elderly population has been increasing rapidly in recent years. From the results it was found that the presence of older drivers significantly reduced intersection capacity at all study sites because of their higher lost times and lower saturation flow rates. Therefore, driving behavior of older drivers should be considered in designing intersections located in places with a significant older driver population. In the research, models were developed to predict start-up lost time and saturation headway values generated by older drivers. Then, the variation in capacities with an increasing percentage of older drivers in the traffic stream was modeled. Finally, adjustment factors for different percentages of older drivers were developed to adjust intersection capacity. These factors are believed to account for the presence of older drivers in the traffic stream. The adjustment factors may be used in capacity analysis and design procedures for intersections with a significant older driver population.

Older drivers and risk to other road users

This paper examines the degree to which older drivers impose an “excess” risk of death or injury serious enough to require hospitalization on other road users; that is, the amount of risk older drivers impose on others above and beyond the amount imposed by drivers who are not yet old. A data set linking crash information from police accident reports to hospital discharge data in Wisconsin, 1991, was used to analyze excess risk associated with older drivers in two ways. First, the difference in the rate of serious injuries to other road users per 100 million driver age-group miles was used to estimate the total number of serious injuries resulting from the excess risk imposed on others by older drivers. Second, statistical models were used to infer the association between driver age and crash severity while conditioning on a variety of crash-specific information. Drivers aged 65–74 did not appear to impose excess risk of either deaths or injuries requiring hospitalization in either the aggregate or individual level analyses. Drivers aged 75 and over are associated with increased injuries to others, although the actual number is very small; the individual crash-level analysis suggests that a non-trivial part of the excess risk found in the aggregate analysis is a product of confounding.

Age Differences in Visual Abilities in Nighttime Driving Field Conditions

This study was conducted to provide field data on age differences in sign legibility and object detection. Two age groups of healthy drivers with normal vision were tested for nighttime visual ability. The older group had an average age of 65.6 years and the younger group averaged 22.5 years. The field study was conducted on a private road with the subjects seated in the front passenger seat. Subjects performed a Landolt ring legibility task for four types of signs; positive and negative contrast, new and worn material. Subjects also performed object detection tasks using a small object and a pedestrian target appearing in average and low reflectance. In addition, sign legibility and object detection were completed for some trials using a simulated inclement weather visor to create a worst-case scenario. The object detection task was also completed in the presence of glare from oncoming headlamps. Results showed that older driver's legibility distances were 65% those of the younger drivers. Age differences in the object detection task ranged from a 20% to a 45% reduction for older drivers across visibility conditions.

Heavy drinking among Norwegian male drunken drivers: a study of gamma-glutamyltransferase.

The distributions of blood alcohol concentrations (BACs) of different age groups of drunken drivers suggested that a large number of the drunken drivers above 29 years of age had high tolerance to alcohol, and many of these might be heavy drinkers. In order to study the extent of heavy drinking, gamma-glutamyltransferase (GGT) activities were measured in 269 blood samples from male drunken drivers using a new method suitable for hemolyzed blood samples. Of the drunken drivers above 29 years of age, 40% had elevated GGT activities, indicating that roughly one-third of these drivers might be heavy drinkers (consuming more than 80 g of alcohol/day). Of the drunken drivers above 29 years of age with BACs above 55 mmol/liter (250 mg/100 ml), 63% had elevated GGT, indicating that a large majority of these drivers were heavy drinkers. Fewer of the younger drivers had elevated GGT activities. The GGT activities of the repeating offenders indicated that the percentage of heavy drinkers in this group was approximately the same as in the total population of apprehended drunken drivers.

Do Drivers of Small Cars Take Less Risk in Everyday Driving?

Previously reported observed data on risky everyday driving are brought together and reanalyzed in order to focus on the relation between risky driving and the size of the car being driven, as indicated by car mass. The measures of risky driving include separation between vehicles in heavy freeway traffic and speed on a two lane road. Observed seat belt use provides a third measure of driver risk. Confounding effects arising from the observed association between car mass and driver age are taken into account by segmenting the data into three driver age groups. Driver risk taking is found to increase with increasing car mass for each of these three aspects of everyday driving. The implications of these results with respect to driver fatality rates are discussed in terms of a simple model relating observed risky driving to the likelihood of involvement in a severe crash.