Effectiveness and acceptance of the intelligent speeding prediction system (ISPS)

Background

The intelligent speeding prediction system (ISPS) is an in-vehicle speed assistance system developed to provide quantitative predictions of speeding. Although the ISPS's prediction of speeding has been validated, whether the ISPS can regulate a driver's speed behavior or whether a driver accepts the ISPS needs further investigation. Additionally, compared to the existing intelligent speed adaptation (ISA) system, whether the ISPS performs better in terms of reducing excessive speeds and improving driving safety needs more direct evidence.

Objectives

An experiment was conducted to assess and compare the effectiveness and acceptance of the ISPS and the ISA.

Method

We conducted a driving simulator study with 40 participants. System type served as a between-subjects variable with four levels: no speed assistance system, pre-warning system developed based on the ISPS, post-warning system ISA, and combined pre-warning and ISA system. Speeding criterion served as a within-subjects variable with two levels: lower (posted speed limit plus 1 mph) and higher (posted speed limit plus 5 mph) speed threshold. Several aspects of the participants’ driving speed, speeding measures, lead vehicle response, and subjective measures were collected.

Results

Both pre-warning and combined systems led to greater minimum time-to-collision. The combined system resulted in slower driving speed, fewer speeding exceedances, shorter speeding duration, and smaller speeding magnitude.

Conclusions

The results indicate that both pre-warning and combined systems have the potential to improve driving safety and performance.     

The impact of childhood symptoms of conduct disorder on driver aggression in adulthood

Background

Despite limited empirical investigation, existing scientific literature suggests that individuals with a history or current diagnosis of conduct disorder (CD) may be more likely to demonstrate reckless and aggressive driving. Much of the limited research in this field examines the impact of childhood CD on driver behaviour and collision risk in young adults. Few if any, studies assess the impact of this disorder on driver behaviour beyond age 21 years. The current research is a population-based study of the impact of CD symptoms during childhood on the risk of engaging in driver aggression during adulthood.

Methods

Data are based on telephone interviews with 5230 respondents who reported having driven in the past year. Data are derived from the 2011–2013 cycles of the CAMH Monitor, an ongoing cross-sectional survey of adults in Ontario, Canada aged 18 years and older. A binary logistic regression analysis of self-reported driver aggression in the previous 12 months was conducted, consisting of measures of demographic characteristics, driving exposure, problem substance use, alcohol- and drug-impaired driving, symptoms of attention deficit hyperactivity disorder, and childhood (before age 15) symptoms of CD.

Results

When entered with demographic characteristics, driving exposure, and other potential confounders, childhood symptoms of CD increased the odds of reporting driver aggression more than two-fold (adjusted OR = 2.12). Exploratory analyses of the interaction between childhood symptoms of CD and age was not a significant predictor of driver aggression.

Conclusions

Results suggest that symptoms of CD during childhood are associated with significantly increased odds of self-reported driver aggression during adulthood. Limitations and future directions of the research are discussed.     

Road safety impact of Ontario street racing and stunt driving law

Objective

The purpose of this study was to conduct a process and outcome evaluation of the deterrent impact of Ontario's street racing and stunt driving legislation which came into effect on September 30, 2007, on collision casualties defined as injuries and fatalities. It was hypothesized that because males, especially young ones, are much more likely to engage in speeding, street racing and stunt driving, the new law would have more impact in reducing speeding-related collision casualties in males when compared to females.

Methods

Interrupted time series analysis with ARIMA modelling was applied to the monthly speeding-related collision casualties in Ontario for the period of January 1, 2002 to December 31, 2010, separately for young male drivers 16–25 years of age (primary intervention group), mature male drivers 26–65 years of age (secondary intervention group), young female drivers 16–25 years of age (primary comparison group) and mature female drivers 26–65 years of age (secondary comparison group). A covariate adjustment using non-speeding casualties was included.

Results

A significant intervention effect was found for young male drivers with, on average, 58 fewer collision casualties per month, but not for mature male drivers, when non-speeding casualties were controlled for. No corresponding effect was observed in either comparison (females) group.

Conclusion

These findings indicate a reduction in speeding-related casualties among young males of 58 fewer casualties per month subsequent to the introduction of Ontario's street racing and stunt driving legislation and suggest the presence of a general deterrent effect.     

Pedestrian crossing situations: Quantification of comfort boundaries to guide intervention timing

Introduction

Technical systems that warn or brake for vehicle–pedestrian encounters reduce injuries more effectively the earlier an intervention is initiated. However, premature intervention can irritate drivers, leading to system deactivation and, consequently, no injury reduction whatsoever. It has been proposed that no intervention should be initiated as long as attentive drivers are within their comfort zones. This study aims at quantifying driver comfort boundaries for pedestrian crossing situations to offer guidance for the appropriate timing of interventions.

Methods

Sixty two volunteers drove through an intersection on a test track at 30 and 50 km/h. A pedestrian dummy was launched from behind an obstruction towards the driving path of the approaching car. Brake onset indicated discomfort. Time to collision (TTC), longitudinal and lateral distance were measured at brake onset.

Results

TTC was independent of driving speed ranging from 2.1 to 4.3 s with a median of 3.2 s. Longitudinal distance ranged from 19 to 48 meters with an apparent difference between driving speeds. Lateral distances differed slightly, but significantly between driving speeds. The median was 3.1 m (3.2 m for 30 km/h and 2.9 m for 50 km/h) and values ranged from 1.9 to 4.1 m. Lateral distance in seconds ranged from 1.9 to 4.3 s with a median value of 3.1 s (3.2 s for 30 km/h and 3.0 s for 50 km/h).

Discussion

TTC was independent of driving speed, trial order and volunteer age. It might be considered suitable to intervene in situations where, for example, 90% of drivers have exceeded their comfort boundary, i.e. when drivers have already initiated braking. This percentile value translates to intervention at a TTC of 2.5 s (95% confidence 2.4–2.7 s). The study was limited to Swedish nationals, fully aware drivers, and two driving speeds, but did not investigate behavioural changes due to system interaction.

Conclusion

This study showed that TTC at brake onset was a suitable measure for the quantification of driver comfort boundaries in pedestrian crossing situations. All drivers applied their brakes prior to 2.1 s TTC.     

Unlicensed driving and other related health risk behaviors: A study of Montana high school students

Purpose

Health risk behaviors tend to cluster in young people, not least among young drivers. Less is known about the health risk profile of young unlicensed drivers. This study investigates health risk behaviors among young unlicensed drivers compared to both their licensed and driving peers, and their non-driving peers.

Methods

High school students participating in the Youth Risk Behavior Surveillance System in Montana (US) and age-eligible to have a driver's license were studied (n = 5985), categorized according to their self-reported car driving and license practice (licensed driving, unlicensed driving, and non-driving). Ten health risk behaviors, of which four were related to car riding/driving, were considered. Multinomial logistic regression was used to compile sex-specific odds ratios (with 95% confidence intervals) of adopting those behaviors using licensed drivers as a reference and adjusting for age and race/ethnicity.

Results

Health risk behaviors tended to be more common among unlicensed drivers than other groups, although some behaviors were prevalent in all groups (i.e., alcohol use and lack of seat belt use). As a consequence, for both male and female students, there was a significant association between unlicensed driving and most health risk behaviors, except for being involved in a physical fight and riding with a drinking driver among female students.

Conclusions

Young unlicensed drivers are more likely than licensed drivers to adopt several health risk behaviors both in car driving/riding or otherwise, in particular alcohol use and cigarette smoking. This challenges any simplistic approach as unlicensed driving in youth is not an isolated act suggesting public health and traffic safety initiatives.     

Speeding by young novice drivers: What can personal characteristics and psychosocial theory add to our understanding?

Purpose

Young novice drivers continue to be overrepresented in fatalities and injuries arising from crashes even with the introduction of countermeasures such as graduated driver licensing (GDL). Enhancing countermeasures requires a better understanding of the variables influencing risky driving. One of the most common risky behaviours performed by drivers of all ages is speeding, which is particularly risky for young novice drivers who, due to their driving inexperience, have difficulty in identifying and responding appropriately to road hazards. Psychosocial theory can improve our understanding of contributors to speeding, thereby informing countermeasure development and evaluation. This paper reports an application of Akers’ social learning theory (SLT), augmented by Gerrard and Gibbons’ prototype/willingness model (PWM), in addition to personal characteristics of age, gender, car ownership, and psychological traits/states of anxiety, depression, sensation seeking propensity and reward sensitivity, to examine the influences on self-reported speeding of young novice drivers with a Provisional (intermediate) licence in Queensland, Australia.

Method

Young drivers (n = 378) recruited in 2010 for longitudinal research completed two surveys containing the Behaviour of Young Novice Drivers Scale, and reported their attitudes and behaviours as pre-Licence/Learner (Survey 1) and Provisional (Survey 2) drivers and their sociodemographic characteristics.

Results

An Akers’ measurement model was created. Hierarchical multiple regressions revealed that (1) personal characteristics (PC) explained 20.3%; (2) the combination of PC and SLT explained 41.1%; (3) the combination of PC, SLT and PWM explained 53.7% of variance in self-reported speeding. Whilst there appeared to be considerable shared variance, the significant predictors in the final model included gender, car ownership, reward sensitivity, depression, personal attitudes, and Learner speeding.

Conclusions

These results highlight the capacity for psychosocial theory to improve our understanding of speeding by young novice drivers, revealing relationships between previous behaviour, attitudes, psychosocial characteristics and speeding. The findings suggest multi-faceted countermeasures should target the risky behaviour of Learners, and Learner supervisors should be encouraged to monitor their Learners’ driving speed. Novice drivers should be discouraged from developing risky attitudes towards speeding.     

What factors influence older people in the decision to relinquish their driver's licence? A discrete choice experiment

Purpose

To investigate the relative importance of a number of key factors that influence older people in the decision to relinquish their driver's licence.

Method

A discrete choice experiment (DCE) was administered as an online survey to Australian adults, 65 years plus (N = 114) who drive, recruited from an online panel. The survey was composed of three main sections. (A) The Adelaide Driving Self Efficacy Scale to assess confidence in driving. The scale is generated from individual's responses about confidence in their driving ability in various situations. (B) The DCE in which respondents were presented with a series of hypothetical binary choice situations and asked to indicate in which situation they would be more likely to relinquish their driving licence. (C) Socio-demographic and health status questions. A conditional logit regression model was adopted to analyse the DCE data.

Results

Older people would be more likely to relinquish their driver's licence due to advanced age, low confidence in driving ability and in situations where their local doctor advises them to cease driving. Other transport options availability and the cost of public transport were not found to be influential to this decision.

Conclusions

Factors pertaining to the individual themselves including advanced old age and low confidence in driving ability may be more influential than environmental factors such as availability of other transport options and the cost of public transport in an older person's decision to relinquish their driving licence.     

Confirmatory factor analysis of the Behaviour of Young Novice Drivers Scale (BYNDS)

Purpose

The greatly increased risk of being killed or injured in a car crash for the young novice driver has been recognised in the road safety and injury prevention literature for decades. Risky driving behaviour has consistently been found to contribute to traffic crashes. Researchers have devised a number of instruments to measure this risky driving behaviour. One tool developed specifically to measure the risky behaviour of young novice drivers is the Behaviour of Young Novice Drivers Scale (BYNDS) (Scott-Parker et al., 2010). The BYNDS consists of 44 items comprising five subscales for transient violations, fixed violations, misjudgement, risky driving exposure, and driving in response to their mood. The factor structure of the BYNDS has not been examined since its development in a matched sample of 476 novice drivers aged 17–25 years.

Method

The current research attempted to refine the BYNDS and explore its relationship with the self-reported crash and offence involvement and driving intentions of 390 drivers aged 17–25 years (M = 18.23, SD = 1.58) in Queensland, Australia, during their first 6 months of independent driving with a Provisional (intermediate) driver's licence. A confirmatory factor analysis was undertaken examining the fit of the originally proposed BYNDS measurement model.

Results

The model was not a good fit to the data. A number of iterations removed items with low factor loadings, resulting in a 36-item revised BYNDS which was a good fit to the data. The revised BYNDS was highly internally consistent. Crashes were associated with fixed violations, risky driving exposure, and misjudgement; offences were moderately associated with risky driving exposure and transient violations; and road-rule compliance intentions were highly associated with transient violations.

Conclusions

Applications of the BYNDS in other young novice driver populations will further explore the factor structure of both the original and revised BYNDS. The relationships between BYNDS subscales and self-reported risky behaviour and attitudes can also inform countermeasure development, such as targeting young novice driver non-compliance through enforcement and education initiatives.     

Impairment of a speed management strategy in young drivers under high cognitive workload

Background

A training method known as Episodic training has shown promise in reducing speeding behavior in young drivers (Prabhakharan and Molesworth, 2011). The present study aimed to investigate how cognitive resources are utilized to implement this behavioral change.

Method

60 participants were randomly divided into four groups and completed a simulated training drive in Week 1 followed by a 10 km simulated test drive in Week 2. As part of the test drive, two groups were asked to complete a secondary task (mental arithmetic task) in addition to the test drive.

Results

The results indicated that implementing a speed management strategy elicited by Episodic training was successful in isolation, but came at a cognitive trade-off when performed in conjunction with a secondary task.

Conclusion

From an applied perspective, these results suggest driver training programmes should compartmentalize driver training in order to reduce the cognitive load experienced by trainee drivers, and hence facilitate in driver skill acquisition.     

The influence of anger,impulsivity, sensation seeking and driver attitudes on risky driving behaviour among post-graduate university students in Durban,South Africa

Introduction

Road traffic accidents (RTAs) constitute a serious global health risk, and evidence suggests that young drivers are significantly overrepresented among those injured or killed in RTAs. This study explores the role of anger, impulsivity, sensation seeking and driver attitudes as correlates for risky driving practices among drivers, drawing comparisons between age and gender.

Method

The study used a cross-sectional survey design, with a sample of 306 post-graduate university students from two universities in Durban, South Africa, who completed the self-administered questionnaire.

Results

The results indicate that drivers with higher driver anger, sensation seeking, urgency, and with a lack of premeditation and perseverance in daily activities were statistically more likely to report riskier driving acts. Males reported significantly more acts of risky driving behaviour (RDB) than females. Driver attitudes significantly predicted self-reported acts of RDB on most indicators. Older drivers (25 years and older) had safer driver attitudes and a lower sense of sensation seeking and urgency in life.

Conclusion

Interventions targeting young drivers, which focus on impeding the manifestation of anger, impulsivity and sensation seeking are recommended. Also, the empirical support for the attitude–behaviour hypothesis evidenced in this study vindicates the development or continuation of interventions that focus on this dynamic.     

Young novice drivers and the risky behaviours of parents and friends during the Provisional (intermediate) licence phase: A brief report

Purpose

While there is research indicating that many factors influence the young novice driver's increased risk of road crash injury during the earliest stages of their independent driving, there is a need to further understand the relationship between the perceived risky driving behaviour of parents and friends and the risky behaviour of drivers with a Provisional (intermediate) licence.

Method

As part of a larger research project, 378 drivers aged 17–25 years (M = 18.22, SD = 1.59, 113 males) with a Provisional licence completed an online survey exploring the perceived riskiness of their parents’ and friends’ driving, and the extent to which they pattern (i.e. base) their driving behaviour on the driving of their parents and friends.

Results

Young drivers who reported patterning their driving on their friends, and who reported they perceived their friends to be risky drivers, reported more risky driving. The risky driving behaviour of young male drivers was associated with the perceived riskiness of their fathers’ driving, whilst for female drivers the perceived riskiness of their mothers’ driving approached significance.

Conclusions

The development and application of countermeasures targeting the risky behaviour of same-sex parents appears warranted by the robust research findings. In addition, countermeasures need to encourage young people in general to be non-risky drivers; targeting the negative influence of risky peer groups specifically. Social norms interventions may minimise the influence of potentially-overestimated riskiness.     

Risky driving behavior among university students and staff in the Sultanate of Oman

Background

There is a well developed literature on research investigating the relationship between various driving behaviors and road crash involvement. However, this research has predominantly been conducted in developed economies dominated by western types of cultural environments. To date no research has been published that has empirically investigated this relationship within the context of the emerging economies such as Oman.

Objective

The present study aims to investigate driving behavior as indexed in the driving behavior questionnaire (DBQ) among a group of Omani university students and staff.

Methods

A convenience non-probability self-selection sampling approach was utilized with Omani university students and staff.

Results

A total of 1003 Omani students (n = 632) and staff (n = 371) participated in the survey. Factor analysis of the BDQ revealed four main factors that were errors, speeding violation, lapses and aggressive violation. In the multivariate logistic backward regression analysis, the following factors were identified as significant predictors of being involved in causing at least one crash: driving experience, history of offenses and two DBQ components, i.e., errors and aggressive violation.

Conclusion

This study indicates that errors and aggressive violation of the traffic regulations as well as history of having traffic offenses are major risk factors for road traffic crashes among the sample. While previous international research has demonstrated that speeding is a primary cause of crashing, in the current context, the results indicate that an array of factors is associated with crashes. Further research using more rigorous methodology is warranted to inform the development of road safety countermeasures in Oman that improves overall Traffic Safety Culture.     

Parental influence on adolescent compliance with graduated driver licensing conditions and crashes as a restricted licensed driver: New Zealand Drivers Study

Aim

To examine the influence of parental knowledge of, and support for graduated driver licensing (GDL) conditions, parental management of adolescent driving and parental driving behaviour on adolescent compliance with GDL conditions and crashes as a restricted licence driver.

Method

This research was part of the New Zealand Drivers Study (NZDS), a prospective cohort study of 3992 newly licensed car drivers. NZDS participants were recruited at the learner licence stage, with follow-up aligned with the GDL stages. At the restricted licence stage 1200 parents of NZDS adolescents, aged 15–17 years at learner licensure, were recruited and completed interviews. 895 of these adolescents progressed to their full licence and completed the full licence interview. These 895 parent–adolescent pairs were the study population in this research. Topics examined included parental knowledge of, and support for GDL conditions, management of adolescent driving (driving rules, adolescent vehicle ownership, delaying licensure), and their own driving behaviours. Outcomes examined were adolescent compliance with GDL restricted licence conditions (night-time and passenger), and crashes as a driver during the restricted licence stage.

Results

After controlling for other variables, factors independently associated with adolescent low compliance with GDL conditions were: low parental knowledge of conditions, parents’ implementing few driving rules, adolescent vehicle ownership, and parent crash involvement. Factors independently associated with adolescents being a crash involved driver were: parents’ actively delaying licensure, adolescent vehicle ownership, and parent crash involvement.

Conclusion

There is increasing recognition of the importance of parental involvement in adolescent driving. The results show that parents are influential in determining adolescent compliance with GDL and risk of crash. Parents can have considerable positive influence on their adolescent's driving through ensuring compliance with the components of GDL, limiting vehicle ownership and by modelling safe driving behaviours.     

Street racing video games and risk-taking driving: An Internet survey of automobile enthusiasts

Purpose

The purpose of this study was to examine the relationships among risky driving attitudes, self-perceptions as a risky driver, playing of “drive’em up” (which rewarded players for frequent traffic and other violations) and “circuit” racing video games as well as self-reported risky driving through a web-based survey of car and racing club members in relation to a socio-cognitive model of the effects of racing video game playing.

Method

An Internet questionnaire was developed and included: (1) self-perceptions as a risky driver scales (Driver Thrill Seeking and Competitive Attitude Toward Driving); (2) attitudes regarding street racing; (3) street racing video game playing, and (4) self-reported risky driving (Risk-Taking Driving Scale). A sequential logistic regression was performed entering age and driving exposure as control variables in the first block, self-perceptions as a risky driver in the second block, attitudes in the third block and playing “drive’em up” and “circuit” racing games in the last block to examine their effects on self-reported risk-taking driving.

Results

A total of 503 survey respondents were included in the analyses and only 20% reported any risk-taking driving. Higher score on the Competitive Attitude Toward Driving Scale, more positive attitudes toward street racing, and more frequent reported playing of “drive’em up” video games were associated with higher odds on the self-reported Risk-Taking Driving Scale. However, the Driver Thrill Seeking Scale and “circuit” video game playing failed to predict self-reported risk-taking driving.

Conclusions

Self-perceptions as a risky driver, positive attitudes toward risky driving and “drive’em up” street-racing games, but not “circuit” racing games, are associated with increased risk-taking driving. These findings are congruent with experimental studies in which games that reward driving violations increased risk taking, suggesting that risk taking may be a function of type of street racing game played by affecting self-perceptions as a risky driver.     

The prevalence and nature of stopped on-the-road driving tests and the relationship with objective performance impairment

Introduction and objectives

The on-the-road driving test in normal traffic is applied to examine the impact of drugs on driving performance. Although participants are accompanied by a licensed driving instructor, under Dutch law, the driver is primarily responsible for safe driving and is not permitted to continue driving when it is judged that the drug compromises safety. This review examined the prevalence and nature of stopped driving tests, and the relationship with Standard Deviation of Lateral Position (SDLP), i.e. the “weaving of the car”.

Materials and methods

A literature search was conducted to gather all publications on clinical trials that applied the on-the-road driving test, examining the effects of Central Nervous System (CNS)-drugs such as anxiolytics, antidepressants, antihistamines, analgesics, and hypnotics.

Results

47 papers reported on 50 Dutch clinical trials in which 1059 subjects participated (903 healthy volunteers and 156 patients). A total of 7232 driving tests were performed; 5050 after drug treatment and 2042 after placebo. 3.1% of all driving tests were terminated before completion: 4.1% after drug treatment, and 0.7% after placebo. The decision to stop a driving test was 3–4 times more often made by the driving instructor than the subject. The most common reasons for stopping were the driver feeling tired or sleepy, or the driving instructor noticing signs of drowsiness and performance impairment. Although SDLP values of stopped driving tests are sometimes high, there is no clear relationship between SDLP (changes from placebo) and the decision to stop a driving test. Based on 8 studies that reported exact data, 39.6% of stopped drivers had a lower and 60.4% had a higher SDLP than 35 cm, i.e. the cut-off point of safe driving. This confirms that perception of the driver as well as judgment by the instructor of driving to be ‘unsafe’ differs between individuals.

Conclusion

Driving tests are sometimes stopped after drug treatment or placebo. The decision to stop driving is not a good correlate of objective performance.     

Does gender moderate the relationship between driver aggression and its risk factors?

Aim

The current study assessed gender as a potential moderator of the relationship between self-reported driver aggression and various demographic variables, general and driving-related risk factors.

Methods

Using data from a general-population telephone survey conducted from July 2002 through June 2005, two approaches to binary logistic regression were adopted. Based on the full dataset (n = 6259), the initial analysis was a hierarchical-entry regression examining self-reported driver aggression in the last 12 months. All demographic variables (i.e., gender, age, income, education, marital status), general risk factors (i.e., psychological distress, binge drinking, cannabis use), and driving-related risk factors (i.e., driving exposure, stressful driving, exposure to busy roads, driving after drinking, driving after cannabis use) were entered in the first block, and all two-way interactions with gender were entered stepwise in the second block. The subsequent analysis involved dividing the sample by gender and conducting logistic regressions with main effects only for males (n = 2921) and females (n = 3338) separately.

Results

Although the prevalence of driver aggression in the current sample was slightly higher among males (38.5%) than females (32.9%), the difference was small, and gender did not enter as a significant predictor of driver aggression in the overall logistic regression. In that analysis, difficulty with social functioning and being older were associated with a reduced risk of driver aggression. Marital status and education were unrelated to aggression, and all other variables were associated with an increased risk of aggression. Gender was found to moderate the relationships between driver aggression and only three variables: income, psychological distress, and driving exposure. Separate analyses on the male and female sub-samples also found differences in the predictive value of income and driving exposure; however, the difference for psychological distress could not be detected using this separate regression approach. The secondary analysis also identified slight differences in the predictive value of four of the risk factors, where the odds ratios for both males and females were in the same direction but only one of the two was statistically significant.

Conclusions

The results demonstrate the importance of conducting the gender analysis using both regression approaches. With few exceptions, factors that were predictive of driver aggression were generally the same for both male and female drivers.     

Distraction and driving: Results from a case–control responsibility study of traffic crash injured drivers interviewed at the emergency room

Background

Use of cellular phones has been shown to be associated with crashes but many external distractions remain to be studied.

Objective

To assess the risk associated with diversion of attention due to unexpected events or secondary tasks at the wheel.

Design

Responsibility case–control study.

Setting

Adult emergency department of the Bordeaux University Hospital (France) from April 2010 to August 2011.

Participants

955 injured drivers presenting as a result of motor vehicle crash.

Main outcome measures

The main outcome variable was responsibility for the crash. Exposures were external distraction, alcohol use, psychotropic medicine use, and sleep deprivation. Potential confounders were sociodemographic and crash characteristics.

Results

Beyond classical risk factor found to be associated with responsibility, results showed that distracting events inside the vehicle (picking up an object), distraction due to driver activity (smoking) and distracting events occurring outside were associated with an increased probability of being at fault. These distraction-related factors accounted for 8% of injurious road crashes.

Limitations

Retrospective responsibility self-assessment.

Conclusions

Diverted attention may carry more risk than expected. Our results are supporting recent research efforts to detect periods of driving vulnerability related to inattention.     

An example of the usefulness of joinpoint trend analysis for assessing changes in traffic safety policies

Aim

To show the usefulness of joinpoint trend analysis for assessing changes in traffic safety policies.

Methods

Trends in driver death rates from traffic injury stratified by alcohol involvement in Spain during 2001–2011 were characterized with joinpoint regression to observe how changes in these rates match in time with the implementation of traffic regulations and interventions.

Results

Both alcohol-related (blood alcohol concentration >0.3 g/l) and non-alcohol-related rates decreased similarly (10–11% annually) during 2001–2011, although the former showed an earlier (2003 joinpoint) acceleration of the downward trend than the latter (2006 joinpoint); both joinpoints matched in time with relevant road safety interventions.

Conclusions

These results, which are consistent with results from previous analytical studies, show that joinpoint trend analysis, although not valid for causal inference, is useful for assessing changes in traffic safety policies. This methodology can be easily extended to other risk factors, such as excessive speeding or not wearing a seat belt.