On-road and simulated driving: concurrent and discriminant validation

Introduction

A converging pair of studies investigated the validity of a simulator for measuring driving performance/skill.

Study 1

A concurrent validity study compared novice driver performance during an on-road driving test with their performance on a comparable simulated driving test.

Results

Results showed a reasonable degree of concordance in terms of the distribution of driving errors on-road and errors on the simulator. Moreover, there was a significant relationship between the two when driver performance was rank ordered according to errors, further establishing the relative validity of the simulator. However, specific driving errors on the two tasks were not closely related suggesting that absolute validity could not be established and that overall performance is needed to establish the level of skill.

Study 2

A discriminant validity study compared driving performance on the simulator across three groups of drivers who differ in their level of experience - a group of true beginners who had no driving experience, a group of novice drivers who had completed driver education and had a learner's permit, and a group of fully licensed, experienced drivers.

Results

The findings showed significant differences among the groups in the expected direction -- the various measures of driving errors showed that beginners performed worse than novice drivers and that experienced drivers had the fewest errors. Collectively, the results of the concurrent and discriminant validity studies support the use of the simulator as a valid measure of driving performance for research purposes.

Impact on industry

These findings support the use of a driving simulator as a valid measure of driving performance for research purposes. Future research should continue to examine validity between on-road driving performance and performance on a driving simulator and the use of simulated driving tests in the evaluation of driver education/training programs.     

Enhancing older driver safety: A driving survey and evaluation of the CarFit program

Objective

To evaluate CarFit, an educational program designed to promote optimal alignment of driver with vehicle.

Methods

A driving activity survey was sent to 727 randomly selected participants living in retirement communities. Drivers (n = 195) were assigned randomly to CarFit intervention (n = 83, M age = 78.1) or Comparison (n = 112, M age = 79.6) groups. After 6 months, participants completed a post-test of driving activity and CarFit recommendations.

Results

Nonconsenting drivers were older and participated in fewer driving activities. CarFit participation was moderate (71%) with 86% of the participants receiving recommendations. 60% followed the recommendations at the 6-month re-evaluation). The CarFit (67.6%) and Comparison (59.3%) groups reported at least one type of self-regulation of driving activity at baseline. There was no significant change in the driving behaviors at the six-month follow-up.

Conclusion

CarFit was able to detect addressable opportunities that may contribute to the safety of older drivers.

Impact on industry

CarFit recommendations may need stronger reinforcement in order to be enacted by a participant.     

What vehicle features are considered important when buying an automobile? An examination of driver preferences by age and gender

Introduction

Certain vehicle features can help drivers avoid collisions and/or protect occupants in the event of a crash, and therefore, might play an important role when deciding which vehicle to purchase. The objective of this study was to examine the importance attributed to key vehicle features (including safety) that drivers consider when buying a car and its association with age and gender.

Methods

A sample of 2,002 Canadian drivers aged 18 years and older completed a survey that asked them to rank the importance of eight vehicle features if they were to purchase a vehicle (storage, mileage, safety, price, comfort, performance, design, and reliability). ANOVA tests were performed to: (a) determine if there were differences in the level of importance between features and; (b) examine the effect of age and gender on the importance attributed to these features.

Results

Of the features examined, safety and reliability were the most highly rated in terms of importance, whereas design and performance had the lowest rating. Differences in safety and performance across age groups were dependent on gender. This effect was most evident in the youngest and oldest age groups.

Conclusions

Safety and reliability were considered the most important features. Age and gender play a significant role in explaining the importance of certain features.

Impact on Industry

Targeted efforts for translating safety-related information to the youngest and oldest consumers should be emphasized due to their high collision, injury, and fatality rates.     

Effect of enhanced seat belt reminders on driver fatality risk

Objective

Enhanced seat belt reminders in automobiles have been shown to increase belt use rates by approximately 3 percentage points. The objective of this study was to estimate the effect of enhanced seat belt reminders on driver fatality risk.

Method

Data included all passenger vehicle driver deaths and vehicle registration counts in the United States for calendar years 2000-2007. Driver fatality rates per vehicle registration per year were compared for otherwise identical vehicle models with and without enhanced seat belt reminders.

Results

Driver fatality rates were 6% lower for vehicles with enhanced seat belt reminders compared with vehicles without enhanced belt reminders. After adjusting for vehicle age differences, the estimated effect of enhanced belt reminders on driver fatality risk ranged from a 9% reduction for General Motors vehicles to a 2% increase for Honda vehicles. Combining all manufacturers, enhanced belt reminders reduced fatality risk by approximately 2%. Although not statistically significant, the 2% reduction in fatality risk agrees with what should be expected from a 3 percentage point increase in seat belt use rates.

Conclusions

Enhanced seat belt reminders have raised driver belt use rates and reduced fatality rates, but more aggressive systems may be needed for some drivers. It can be inferred that nonfatal injury rates also have been reduced.

Impact on Industry

Manufacturers should be encouraged to put enhanced seat belt reminders on all vehicles as soon as possible.     

"The little squealer" or "the virtual guardian angel"? Young drivers' and their parents' perspective on using a driver monitoring technology and its implications for parent-young driver communication

Introduction

In-vehicle driving monitoring technologies have the potential to enable young drivers to learn from self-assessment. However, their use is largely dependent on parental involvement.

Method

A total of 79 interviews were conducted with young drivers and parents regarding this technology and its use. Most had the experience of having an in-vehicle data recorder installed in the vehicle driven by the young drivers. Parents and the young drivers expressed both appreciation as well as reservations about its potential as a means to enhance the driving safety of young drivers.

Results

A surprising finding was that some parents did not check the feedback and said they relied on the young driver to do so. Main concerns related to privacy, parent-young driver relationship, self-esteem and confidence, constructive use of the feedback data, and the limitations of the documentation that can be done by the technology.

Conclusions

Providing parents and young drivers with a support system and tools to discuss and utilize the feedback are underscored. Challenges include addressing the invasion of young drivers’ privacy and gender differences, and using the monitoring-capacity of the technology to enhance safe driving practices. Implications for programs to enhance communication and a dialogical approach between parents and young drivers are discussed.     

Self-assessed driver competence among novice drivers - a comparison of driving test candidate assessments and examiner assessments in a Dutch and Finnish sample

Problem

This study examined novice drivers’ overconfidence by comparing their self-assessed driver competence with the assessments made by driving examiners.

Method

A Finnish (n = 2,739) and a Dutch sample (n = 239) of drivers license candidates assessed their driver competence in six areas and took the driving test.

Result and Discussion

In contrast to previous studies where drivers have assessed their skill in comparison to the average driver, a smaller proportion overestimated and a larger proportion made realistic self-assessments of their driver competence in the present study, where self-assessments were compared with examiner assessments. Between 40% and 50% of the candidates in both samples made realistic assessments and 30% to 40% overestimated their competence. The proportion of overestimation was greater in the Dutch than in the Finnish sample, which might be explained by greater possibilities for practicing self-assessment in the Finnish driver education system. Similar to other self-assessment studies that indicate that incompetence is related to overestimation, a larger proportion of candidates that failed the test overestimated their skill compared to those who passed. In contrast to other studies, males did not overestimate their skills more than females, and younger driver candidates were not more overconfident than older drivers.

Impact on traffic safety

Although a great proportion of the candidates made a realistic assessment of their own driver competence, overestimation is still a problem that needs to be dealt with. To improve the accuracy of novice drivers’ self-assessment, methods for self-assessment training should be developed and implemented in the driver licensing process.     

Survival risk factors for fatal injured car and motorcycle drivers in single alcohol-related and alcohol-unrelated vehicle crashes

Introduction

A high percentage of drivers who die as a result of a single vehicle crash are under the influence of alcohol. We aimed to better understand the prevalence of these fatalities and the ratio of death to injuries based on various risk factors. We focused on alcohol-related and -unrelated single-vehicle crashes to investigate the influence of such risk factors on the time until death for car and motorcycle drivers.

Methods

We combined data from national police reports and a vital registration database in Taiwan. Survival analysis using Cox regression models was used to identify the risk factors of time until death.

Results

Overall, nearly 60% of car driver fatalities and 40% of motorcycle driver fatalities involved the consumption of alcohol. Survival analysis of single-vehicle crashes suggested that the traffic island separation between a car moving at a higher speed and motorcycle traffic resulted in a higher risk of death over time for motorcycle drivers who consumed alcohol. The factors attributed to a higher risk of death over time for motorcycle drivers were older age, crashing into trees, night-time driving, driving on curved roads, and driving on local roads. Driving without restraints and driving on roads with higher speed limits attributed to a higher risk of death over time for car drivers.

Conclusions

The factors that influence the risk of death over time in a motor-vehicle accident involving alcohol depended on different elements, which should each be considered when attempting to reduce this risk.

Impact on Industry

More efforts should be made to investigate the various risk factors in areas with large motorcycle populations.     

Predicting driver drowsiness using vehicle measures: Recent insights and future challenges

Introduction

Driver drowsiness is a significant contributing factor to road crashes. One approach to tackling this issue is to develop technological countermeasures for detecting driver drowsiness, so that a driver can be warned before a crash occurs.

Method

The goal of this review is to assess, given the current state of knowledge, whether vehicle measures can be used to reliably predict drowsiness in real time.

Results

Several behavioral experiments have shown that drowsiness can have a serious impact on driving performance in controlled, experimental settings. However, most of those studies have investigated simple functions of performance (such as standard deviation of lane position) and results are often reported as averages across drivers, and across time.

Conclusions

Further research is necessary to examine more complex functions, as well as individual differences between drivers.

Impact on Industry

A successful countermeasure for predicting driver drowsiness will probably require the setting of multiple criteria, and the use of multiple measures.     

Increasing self-awareness among older drivers: The role of self-screening

Introduction

Self-screening by older drivers has shown considerable promise for increasing self-awareness about functional abilities associated with safe driving. The purpose of this study was to improve upon existing self-screening instruments by focusing entirely on “health concerns” that affect driving - that is, the symptoms that people experience due to medical conditions and the medications used to treat them - rather than the medical conditions or medications themselves.

Method

A computer-based, easy-to-use self-screening instrument for older drivers was developed to provide individualized feedback intended to increase self-awareness about declines in driving-related abilities, as well as suggestions for behavioral changes or safety tips to maintain safe driving, further evaluation from a physician/health professional, and vehicle modifications to help compensate for driving-related declines.

Results

This paper describes the development of the self-screening instrument and summarizes findings relative to increasing self-awareness among older drivers. This research represents an important first step in improving self-awareness among older drivers through self-screening.     

A traffic safety evaluation of California's traffic violator school citation dismissal policy

Introduction

This study evaluated California's traffic violator school (TVS) citation dismissal policy.

Method

This study identified and compared two large samples of drivers either completing a TVS (N = 210,015) or convicted of a traffic citation (N = 168,563).

Results

Prior to adjudication, the TVS group had characteristics (e.g., lower prior conviction rate and smaller proportion of males) that were predictive of a lower subsequent crash risk. However, the TVS group exhibited significantly more crashes than did the convicted group in the subsequent one-year period. The difference (4.83%) increased to 10% after adjusting for the more favorable characteristics of the TVS group. The TVS group also had a higher adjusted subsequent crash rate at each prior driver record entry level, reflecting a loss in the general and specific deterrence of the non-conviction masked status of TVS dismissed citations. It was reported that the TVS dismissal policy results in approximately 12,300 additional crashes annually with economic costs of approximately $398,000,000.

Conclusions

The avoidance of licensing actions resulting from the dismissal policy assists in explaining why the driving public is exposed to an increased crash risk. A number of recommendations are offered to reduce the negative traffic safety impact of the TVS citation dismissal policy.     

Older driver retraining: An updated systematic review of evidence of effectiveness

Problem and Objective

The number of older drivers who might benefit from driver retraining is growing. A previous review on the effectiveness of older driver retraining included intervention studies up to 2004. The objective was to perform an updated systematic review of the effectiveness of older driver retraining for improving driving-related skills and reducing crash rates.

Method

Articles published from 2004-2008 were grouped according to the intervention provided and outcome studied. Randomized clinical trials (RCTs) were appraised using the Physiotherapy Evidence Database (PEDro) Scale and scored for quality according to their internal validity. Each intervention's effectiveness was then rated and assigned a level of evidence by combining pre- and post- 2004 findings.

Results

Three RCTs and one matched-pairs cohort design met the inclusion criteria. There is strong evidence (Level 1a) that education combined with on-road training improves driving performance and moderate evidence (Level 1b) that it improves knowledge. There is moderate evidence (Level 1b) that physical retraining improves driving performance. There is moderate evidence (Level 1b) that an educational intervention curriculum alone is not effective in reducing crashes.

Summary

The updated evidence on the effectiveness of retraining aimed at older drivers is sufficiently encouraging to merit assertive health promotion actions regarding intervention and program planning.

Impact on Industry

These positive findings warrant a comprehensive plan that has both behavioral and monetary incentives encouraging older driver participation in programs aimed at driver safety.     

Does the built environment affect when American teens become drivers? Evidence from the 2001 National Household Travel Survey

Problem

Motor vehicle crashes are the most common cause of death for American adolescents. However, the impact of where teens live on when they begin driving has not been studied.

Method

Data from the 2001 National Household Travel Survey were used to estimate the effect of residential density on the driver status of teens aged 16 to 19 years after matching on demographic characteristics.

Results

Controlling for demographic characteristics, 16 and 17 year old teens in high density neighborhoods had driver rates 15 percentage points below teens living in less dense areas (p < 0.001). The effect for 18 and 19 year olds was a 9 percentage point decrease (p < 0.001).

Summary

These results suggest teens living in less dense and more sprawling communities initiate driving at a younger age than comparable teens in compact areas, placing them at increased risk for crash related injuries. Impact on Industry: The role of environmental factors, such as neighborhood walkability and provision of transit, should be considered in young driver programs.     

Validity of police-reported alcohol involvement in fatal motor carrier crashes in the United States between 1982 and 2005

Objective

To examine the validity of police-reported alcohol data for drivers involved in fatal motor carrier crashes.

Material and Methods

We determined the availability of blood alcohol concentration (BAC) and police-reported alcohol data on 157,702 drivers involved in fatal motor carrier crashes between 1982 - 2005 using Fatality Analysis and Reporting System (FARS) data. Drivers were categorized as motor carrier drivers if they operated a vehicle with a gross vehicle weight rating of greater than 26,000 pounds. Otherwise, they were classified as non motor carrier drivers. The sensitivity and specificity of police-reported alcohol involvement were estimated for both driver types.

Results

Of the 157,702 drivers, 18% had no alcohol information, 15% had BAC results, 42% had police-reported alcohol data, and 25% had both. Alcohol information varied significantly by driver, crash, and vehicle characteristics. For example, motor carrier drivers were significantly more likely (51%) to have BAC testing results compared to non motor carrier drivers (31%) (p < 0.001). The sensitivity of police-reported alcohol involvement for a BAC level ≥ 0.08 was 83% (95% CI 79%, 86%) for motor carrier drivers and 90% (95% CI 89%, 90%) for non motor carrier drivers. The specificity rates were 96% (95% CI 95%, 96%) and 91% (95% CI 90%, 91%), respectively.

Conclusions

The sensitivity and specificity of police-reported alcohol involvement are reasonably high for drivers involved in fatal motor carrier crashes. Further research is needed to determine the extent to which the accuracy of police-reported alcohol involvement may be overestimated because of verification bias.

Impact on the Industry

Based on the results of this study, the federal government should continue to work with states to strengthen their strategies to increase chemical testing of all drivers involved in fatal crashes.     

Choice of teenagers' vehicles and views on vehicle safety: survey of parents of novice teenage drivers

Objective

To examine parental decisions about vehicles driven by teenagers and parental knowledge of vehicle safety.

Methods

About 300 parents were interviewed during spring 2006 in Minnesota, North Carolina, and Rhode Island while teenagers took their first on-road driving tests.

Results

Fewer than half of parents surveyed said teenagers would be the primary drivers of the chosen vehicles. Parents most often cited safety, existing family vehicle, and reliability when explaining the choices for their teenagers’ vehicles. About half of the vehicles intended for teenagers were small/mini/sports cars, pickups, or SUVs — vehicles considered less safe for teenagers than midsize/large cars or minivans. A large majority of vehicles were 2001 models or earlier. Vehicles purchased in anticipation of adding a new driver to the family were more likely to be the sizes/types considered less safe than vehicles already owned. Few parents insisted on side airbags or electronic stability control, despite strong evidence of their safety benefits. Even when asked to identify ideal vehicles for their teenagers to drive, about half of parents identified less safe vehicle sizes/types. Most parents knew that midsize/large vehicles are safer than small vehicles, and at least half of parents said SUVs and pickups are not safe for teenage drivers, citing instability.

Conclusions

The majority of parents understood some of the important criteria for choosing safe vehicles for their teenagers. However, parents actually selected many vehicles for teenagers that provide inferior crash protection.

Impact on industry

Vehicle safety varies substantially by vehicle size, type, and safety features. Many teenagers are driving inferior vehicles in terms of crashworthiness and crash avoidance.     

Absence behavior as traffic crash predictor in bus drivers

Problem

Various indicators of health have been shown to be associated with traffic crash involvement. As general health is also related to absence from work, the latter variable may be more strongly related to crashes, especially for professional drivers.

Method

Bus driver absence from work was analyzed in association with their crash records. Two British samples and one Swedish sample were used.

Results

One of the British samples yielded fair correlations between crash record and absence, while for the other the effect was restricted to the first three months of driving. The Swedish data had effects in the expected direction but these were not significant.

Discussion

The use of an indirect, overall measurement of health, may be a viable method for predicting the traffic crash involvement for professional drivers, although replications are needed in larger samples and other populations.

Impact on industry

The use of absence records for the identification of at risk drivers would seem to be a simple and useful method for companies with major fleets, and it also shows the importance of promoting employee health and well being at work as a potential method of reducing the cost, not only of absenteeism, but also of crashes in company vehicles.     

Are drivers' comparative risk judgments about speeding realistic?

Introduction

This study focused on comparative judgments about speeding risks among young drivers who have a high risk of being involved in a traffic accident.

Method

We examined (a) how these drivers assess their risk of sanctions and their risk of causing an automobile crash because of speeding in comparison to the estimated risks of other drivers, and (b) how realistic their comparative risk judgments are. We measured the relationship between the drivers' comparative risk judgments, self-reported speeding, and driving-related sensation-seeking. We hypothesized that (a) they would think they have less risk of sanctions and of causing a car accident than others, and (b) their comparative judgments of speeding risks would be linked to self-reported speeding and driving-related sensation-seeking. The study was based on a computerized questionnaire survey conducted with 3,002 young drivers (mean age = 22.3) administered by professional investigators.

Results

The results confirmed our hypotheses.

Impact on Industry

In order to improve the effectiveness of prevention measures and to evaluate the effect of them, road-safety interventions should take into account comparative risk judgments about the targeted risk behavior.     

Dissociation between driving performance and drivers' subjective estimates of performance and workload in dual-task conditions

Introduction

The current study measured how concurrent driving and in-vehicle activities of different levels of engagement varied in terms of performance and subjective estimates of demand and performance.

Method

In this test track study, 41 younger and older drivers completed a series of cognitive tasks while driving an instrumented vehicle. One task involved an engaging guessing game where drivers tried to guess the identity of an object. The other task involved a simple mental arithmetic task.

Results

We observed some dissociation between drivers' performance and their subjective reports. For instance, drivers tended to estimate their performance as better for the more engaging guessing task than the arithmetic task, though their performance was actually worse. At the same time, subjective estimates of workload across the two tasks did not vary in the dual-task condition even though they did in the single-task baseline conditions, suggesting that drivers failed to account for the added demands in dual-task situations.

Conclusions

We discuss the implications of these findings for driver safety.

Impact on Industry

Crashes due to distraction can carry tremendous costs for employers, in terms of injury, disability, and loss of potentially productive work years, whether these crashes occur on or off the job.     

Crash involvement during the different phases of the New Zealand Graduated Driver Licensing System (GDLS)

Introduction

The New Zealand Graduated Driver Licensing System (GDLS) is designed to allow novice drivers to gain driving experience under conditions of reduced risk.

Method

To examine the effectiveness of the GDLS, an analysis of how the crash involvement of novice drivers changes as drivers move through the GDLS was undertaken. Crash profiles were created by data matching the New Zealand license and crash databases, covering a time period from 1999-2006.

Results

The crash profiles show that the initial learner period of the GDLS is relatively safe and the time at which novice drivers have the highest rate of crash involvement is during the first few months of solo driving. Analysis using logistic regression also showed an effect of age and gender, with higher crash involvement associated with younger drivers and males. In addition, individuals who gained a full license within 12-18 months of holding a restricted license, due to completion of a time-discount associated educational program, had a higher level of involvement in crashes than individuals who gained a full license after 18 months.

Conclusions

The crash profiles provide an insight into the crash risk associated with different phases of the New Zealand GDLS.

Impact on Industry

Increasing the age at which drivers first begin to solo drive and the removal of the time-discount associated with completion of an educational program should be considered.     

Injury severity analysis of accidents involving young male drivers in Great Britain

Introduction

Young male drivers are over-represented in traffic accidents; they were involved in 14% of fatal accidents from 1991 to 2003 while holding only 8% of all drivers licenses in the UK. In this study, a subset of the UK national road accident data from 1991 to 2003 has been analyzed. The primary aim is to determine how to best use monetary and progressive resources to understand how road safety measures will reduce the severity of accidents involving young male drivers in both London and Great Britain.

Method

Ordered probit models were used to identify specific accident characteristics that increase the likelihood of one of three categorical outcomes of accident severity: slight, serious, or fatal.

Results

Characteristics found to lead to a higher likelihood of serious and fatal injuries are generally similar across Great Britain and London but are different from those predicted to lead to a higher likelihood of slight injuries. Those characteristics predicted to lead to serious and fatal injuries include driving in darkness, between Friday and Sunday, on roads with a speed limit of 60 mph, on single carriageways, overtaking, skidding, hitting an object off the carriageway, and when passing the site of a previous accident. Characteristics predicted to lead to slight injuries include driving in daylight, between Monday and Thursday, on roads with a speed limit of 30 mph or less, at a roundabout, waiting to move, and when an animal is on the carriageway.

Impact on Industry

These results aid the selection of policy options that are most likely to reduce the severity of accidents involving young male drivers.     

A comparison of web-based and telephone surveys for assessing traffic safety concerns, beliefs, and behaviors

Introduction

The purpose of this investigation was to compare the results of a web-based and a telephone interview survey measuring driver concerns about a variety of traffic safety issues, their beliefs, and specific driving behaviors.

Method

State-wide, annual random digit-dial telephone surveys and web-based surveys were conducted in Maryland. A total of 1,700 drivers were surveyed by telephone and 6,806 took a web survey.

Results

Telephone respondents were more likely to be female and older. Web respondents were more likely to be white and not Latino/Hispanic. After controlling for demographic differences, telephone survey respondents were more likely to be concerned about traffic safety. They were more likely to believe that sobriety checkpoints reduce drunk driving (OR = 2.18, 95% CI 1.94, 2.45), they would be ticketed for not wearing a seat belt (OR = 1.26, 95% CI 1.12, 1.43), and they would be stopped by the police if they drove after drinking too much (OR = 1.17, 95% CI 1.03, 1.32). They were less likely to report a variety of risky behaviors including using a cell phone while driving (OR = .54, 95% CI .48, .61) and driving 10+ mph over the speed limit (OR = .81, 95% CI .72, .91), but were more likely to report having been ticketed for a moving violation in the last month (OR = 2.22, 95% CI 1.70, 2.90). Suggestions are offered for overcoming potential sources of sampling bias.

Impact on Industry

Web-based surveys produce substantially different results than random-digit-dial telephone surveys, when used for public assessments of traffic safety concerns and behaviors.