Distraction-induced driving error: An on-road examination of the errors made by distracted and undistracted drivers

This study explored the nature of errors made by drivers when distracted versus not distracted. Participants drove an instrumented vehicle around an urban test route both while distracted (performing a visual detection task) and while not distracted. Two in-vehicle observers recorded the driving errors made, and a range of other data were collected, including driver verbal protocols, forward, cockpit and driver video, and vehicle data (speed, braking, steering wheel angle, etc.). Classification of the errors revealed that drivers were significantly more likely to make errors when distracted; although driving errors were prevalent even when not distracted. Interestingly, the nature of the errors made when distracted did not differ substantially from those made when not distracted, suggesting that, rather than making different types of errors, distracted drivers simply make a greater number of the same error types they make when not distracted. Avenues for broadening our understanding of the relationship between distraction and driving errors are discussed along with the advantages of using a multi-method framework for studying driver behaviour.     

Assessing the driving performance of older adult drivers: on-road versus simulated driving

To validate a laboratory-based driving simulator in measuring on-road driving performance, 129 older adult drivers were assessed with both the simulator and an on-road test. The driving performance of the participants was gauged by appropriate and reliable age-specific assessment criteria, which were found to be negatively correlated with age. Using principal component analysis, two performance indices were developed from the criteria to represent the overall performance in simulated driving and the on-road assessment. There was significant positive association between the two indices, with the simulated driving performance index explaining over two-thirds of the variability of the on-road driving performance index, after adjustment for age and gender of the drivers. The results supported the validity of the driving simulator and it is a safer and more economical method than the on-road testing to assess the driving performance of older adult drivers.     

Validity and reliability of the on-road driving assessment with senior drivers

The on-road driving assessment is widely regarded as the criterion measure for driving performance despite a paucity of evidence concerning its psychometric properties. The purpose of this study was 2-fold. First, we examined the psychometric properties of an on-road driving assessment with 100 senior drivers between 60 and 86 years (80 healthy volunteers and 20 with specific vision deficits) using Rasch modeling. Second, we compared the outcome of the gestalt decision made by trained professionals with that based on weighted error scores from the standardized assessment. Rasch analysis provided good evidence for construct validity and inter-rater reliability of the on-road assessment and some evidence for internal reliability. Goodness of fit statistics for all items were within an acceptable range and the item hierarchy was logical. The test had a moderate reliability index (0.67). The best cut off score yielded sensitivity of 81% and specificity of 95% compared with the gestalt decision. Further research is required with less competent drivers to more fully examine reliability. Healthy senior drivers failed to check blind spots when changing lanes and made errors when asked to report road markings and traffic signs as they drove. In addition unsafe drivers had difficulty negotiating intersections and lane changes.     

Mental workload when driving in a simulator: Effects of age and driving complexity

Driving errors for older drivers may result from a higher momentary mental workload resulting from complex driving situations, such as intersections. The present study examined if the mental workload of young and older active drivers vary with the difficulty of the driving context. We adopted the probe reaction time (RT) technique to measure the workload while driving in a simulator. The technique provided clear instructions about the primary (driving) and secondary (RT) tasks. To avoid structural interference, the secondary task consisted of responding as rapidly as possible with a vocal response (“top”) to an auditory stimulus. Participants drove through a continuous 26.4-km scenario including rural and urban sections and probes (stimuli) were given in a baseline static condition and in three different driving contexts embedded into the overall driving scenario. Specifically, stimuli were given randomly when (a) driving on straight roads at a constant speed, (b) approaching intersections for which the driver had to stop the car, and (c) when overtaking a slower vehicle. Unless a driving error was made, drivers did not need any emergency responses. Reaction time was defined as the temporal interval between the auditory stimulus and the onset of the corresponding verbal response detected from the analog signal of a piezo-electric microphone fixed on a headset (ms accuracy). Baseline RTs were similar for both groups. Both groups showed longer RTs when driving and RTs increased as the complexity of the driving contexts increased (driving straights, intersections, overtaking maneuvers). Compared to younger drivers, however, older drivers showed longer RTs for all driving contexts and the most complex driving context (overtaking maneuvers) yielded a disproportionate increase. In conclusion, driving leads to a greater mental workload for the older drivers than for the younger drivers and this effect was exacerbated by the more complex driving context (overtaking maneuvers).     

An on-road assessment of cognitive distraction: impacts on drivers' visual behavior and braking performance

In this on-road experiment, drivers performed demanding cognitive tasks while driving in city traffic. All task interactions were carried out in hands-free mode so that the 21 drivers were not required to take their visual attention away from the road or to manually interact with a device inside the vehicle. Visual behavior and vehicle control were assessed while they drove an 8 km city route under three conditions: no additional task, easy cognitive task and difficult cognitive task. Changes in visual behavior were most apparent when performance between the No Task and Difficult Task conditions were compared. When looking outside of the vehicle, drivers spent more time looking centrally ahead and spent less time looking to the areas in the periphery. Drivers also reduced their visual monitoring of the instruments and mirrors, with some drivers abandoning these tasks entirely. When approaching and driving through intersections, drivers made fewer inspection glances to traffic lights compared to the No Task condition and their scanning of intersection areas to the right was also reduced. Vehicle control was also affected; during the most difficult cognitive tasks there were more occurrences of hard braking. Although hands-free designs for telematics devices are intended to reduce or eliminate the distraction arising from manual operation of these units, the potential for cognitive distraction associated with their use must also be considered and appropriately assessed. These changes are captured in measures of drivers' visual behavior.     

Cognitive functioning differentially predicts different dimensions of older drivers’ on-road safety

The extent to which deficits in specific cognitive domains contribute to older drivers’ safety risk in complex real-world driving tasks is not well understood. We selected 148 drivers older than 70 years of age both with and without neurodegenerative diseases (Alzheimer disease–AD and Parkinson disease–PD) from an existing driving database of older adults. Participant assessments included on-road driving safety and cognitive functioning in visuospatial construction, speed of processing, memory, and executive functioning. The standardized on-road drive test was designed to examine multiple facets of older driver safety including navigation performance (e.g., following a route, identifying landmarks), safety errors while concurrently performing secondary navigation tasks (“on-task” safety errors), and safety errors in the absence of any secondary navigation tasks (“baseline” safety errors). The inter-correlations of these outcome measures were fair to moderate supporting their distinctiveness. Participants with diseases performed worse than the healthy aging group on all driving measures and differences between those with AD and PD were minimal. In multivariate analyses, different domains of cognitive functioning predicted distinct facets of driver safety on road. Memory and set-shifting predicted performance in navigation-related secondary tasks, speed of processing predicted on-task safety errors, and visuospatial construction predicted baseline safety errors. These findings support broad assessments of cognitive functioning to inform decisions regarding older driver safety on the road and suggest navigation performance may be useful in evaluating older driver fitness and restrictions in licensing.     

Overly cautious and dangerous: An empirical evidence of the older driver stereotypes

Negative comments regarding the competency of older drivers are frequently heard in the general population. While negative stereotypes of older drivers seem to be present, their existence has yet to be empirically validated. We thus investigated the stereotypes pertaining to older drivers in two experiments. In both experiments young adults viewed 12 simulated clips of three categories of driving behaviors (i.e., younger adults’ unsafe behaviors, older drivers’ unsafe behaviors and appropriate-safe driving behaviors) without knowing the driver's age. They were asked to rate how representative the behaviors were of a typical younger, middle-aged, or older driver. Experiment 1 showed that older drivers’ unsafe behaviors were rated as significantly more representative of the typical older driver, while young adults’ unsafe behaviors were perceived as significantly more representative of the typical younger driver. In Experiment 2, younger participants viewed the same clips but were only asked to indicate whether the observed behavior was representative or not of the typical older driver. The main findings were replicated. When asked to describe the main features of the typical older drivers, participants qualified them as being overly cautious, uncomfortable behind the wheel, and unsafe and dangerous. The potential implications on driving performance of older drivers and on driving cessation and are discussed.     

Older driver distraction: A naturalistic study of behaviour at intersections

This study examined older driver engagement in distracting behaviours (secondary activities) at intersections using naturalistic driving data from a larger study based in Melbourne, Australia. Of interest was whether engagement in secondary activities at intersections was influenced by factors such as driver gender and situational variables, in particular, those relating to the complexity of the driving environment. Specifically we expected that when making left/right turns, older drivers would reduce the proportion of time engaged in secondary behaviours at intersections which required gap judgements (partly controlled or uncontrolled) compared with intersections that were fully controlled by traffic signals. Consideration was given to engagement in secondary activity with hands off the wheel and when the vehicle was moving versus stationary. Older drivers aged between 65 and 83 years drove an instrumented vehicle (IV) on their regular trips for approximately two weeks. The IV was equipped with a video camera system, enabling recording of the road environment and driver and a data acquisition unit, enabling recording of trip distance, vehicle speed, braking, accelerating, steering and indicator use. Driving experience and demographics were collected and functional abilities were assessed using the Useful Field of View (UFOV), Trail Making Test B, Mini Mental Status Examination (MMSE), visual acuity and contrast sensitivity. The study yielded a total of 371 trips with 4493 km (99.8 h) of naturalistic driving data including 1396 left and right turns. Trips were randomly selected from the dataset and in-depth analysis was conducted on 200 intersection manoeuvres (approximately 50% left turns, 50% right turns). The most frequently observed secondary activities were scratching/grooming (42.5%), talking/singing (30.2%) and manipulating the vehicle control panel (12.2%). Glances “off road” 2 s or longer were associated with reading, reaching and manipulation of the vehicle control panel. Hands off the wheel was associated with reading. Key parameters associated with the percent of intersection time that drivers engaged in secondary activities were intersection complexity, vehicle status (moving vs. stationary) and traffic density. In conclusion, older drivers appeared to engage selectively in secondary activities according to roadway/driving situations, supporting the notion that drivers self-regulate by engaging in secondary tasks less frequently when the driving task is more challenging compared with less challenging manoeuvres.     

Discrepancy analysis of driving performance of taxi drivers and non-professional drivers for red-light running violation and crash avoidance at intersections

Due to comfort, convenience, and flexibility, taxis have become increasingly more prevalent in China, especially in large cities. However, many violations and road crashes that occurred frequently were related to taxi drivers. This study aimed to investigate differences in driving performance between taxi drivers and non-professional drivers from the perspectives of red-light running violation and potential crash involvement based on a driving simulation experiment. Two typical scenarios were established in a driving simulator, which includes the red-light running violation scenario and the crash avoidance scenario. There were 49 participants, including 23 taxi drivers (14 males and 9 females) and 26 non-professional drivers (13 males and 13 females) recruited for this experiment. The driving simulation experiment results indicated that non-professional drivers paid more attention to red-light running violations in comparison to taxi drivers who had a higher probability of red-light running violation. Furthermore, it was found that taxi drivers were more inclined to turn the steering wheel in an attempt to avoid a potential collision and non-professional drivers had more abrupt deceleration behaviors when facing a potential crash. Moreover, the experiment results showed that taxi drivers had a smaller crash rate compared to non-professional drivers and had a better performance in terms of crash avoidance at the intersection.     

Demographic factors, fatigue, and driving accidents: An examination of the published literature

This article reviews the literature pertaining to the association between demographic variables (e.g., age, sex, race, socio-economic status) with fatigue, and when feasible, accident risk. It also explores their potential influence and interaction with some working arrangements, commute time, personality characteristics, and circadian chronotype. Fatigue has been implicated in a range of impairments that can have detrimental effects on individuals, and it is differentially associated with conventional demographic variables. However, several major methodological limitations prevent clear conclusions. First, there is absence of a shared definition both within and across disciplines. Second, although fatigue has been investigated using a variety of diverse designs, they have either been too weak to substantiate causality or lacked ecological validity. Third, while both subjective and objective measures have been used as dependent variables, fatigue has been more often found to be more strongly linked with the former. Fourth, with the exception of age and sex, the influence of other demographic variables is unknown, since they have not yet been concomitantly assessed. In instances when they have been assessed and included in statistical analyses, they are considered as covariates or confounders; thus, their contribution to the outcome variable is controlled for, rather than being a planned aspect of investigation. Because the interaction of demographic factors with fatigue is largely a neglected area of study, we recommend greater interdisciplinary collaborations, incorporation of multiple demographic variables as independent factors, and use of within-participant analyses. These recommendations would provide meaningful results that may be used to inform public policy and preventive strategies.     

An exploration of the perceptions of the average driver''s speed compared to perceived driver safety and driving skill

This study investigates the self-enhancement bias in driver attitudes, the finding that drivers rate themselves better than the average driver on safety and skill perceptions (Svenson, 1978 and Svenson, 1981; McCormick et al., 1986). A sample of 86 New Zealand drivers were asked their perceptions of their own and others' speeds in two conditions, 50 km/h and 100 km/h. The results established the self-enhancement bias for speed and safety, but not skill. Between 85% and 90% of drivers claimed to drive slower than the ‘average driver.' A new methodological technique derived from Harré and Gillett (1994) was used to investigate the direction of the self-enhancement bias. The results support the Downward Comparison Theory (Wills, 1981) because drivers consider other drivers negatively, rather than exaggerating their self-perceptions.     

The impact of high-risk drivers and benefits of limiting their driving degree of freedom

The perception of drivers regarding risk-taking behaviour is widely varied. High-risk drivers are the segment of drivers who are disproportionately represented in the majority of crashes. This study examines the typologies of drivers in risk-taking behaviour, the common high-risk driving errors (speeding, close following, abrupt lane-changing and impaired driving), their safety consequences and the technological (ITS) devices for their detection and correction. Limiting the driving degree of freedom of high-risk drivers is proposed and its benefits on safety as well as traffic operations are quantified using VISSIM microscopic traffic simulation at various proportions of high-risk drivers; namely, 4%, 8% and 12%. Assessment of the safety benefits was carried out by using the technique of simulated vehicle conflicts which was validated against historic crashes, and reduction in travel time was used to quantify the operational benefits. The findings imply that limiting the freedom of high-risk drivers resulted in a reduction of crashes by 12%, 21% and 27% in congested traffic conditions; 9%, 13% and 18% in lightly congested traffic conditions as well as 9%, 10% and 17% in non-congested traffic conditions for high-risk drivers in proportions of 4%, 8% and 12% respectively. Moreover, the surrogate safety measures indicated that there was a reduction in crash severity levels. The operational benefits amounted to savings of nearly 1% in travel time for all the proportions of high-risk drivers considered. The study concluded that limiting the freedom of high-risk drivers has safety and operational benefits; though there could be social, legal and institutional concerns for its practical implementation.     

Aggressive driving: an observational study of driver, vehicle, and situational variables

Over 2000 aggressive driving behaviors were observed over a total of 72 h at six different sites. The behaviors selected for observation were those that are commonly included in "aggressive driving" lists, and they consisted of honking, cutting across one or more lanes in front of other vehicles, and passing on the shoulders. In addition, an exposure sample of 7200 drivers were also observed at the same times and places. Relative risks (RRs) and odds ratios (ODs) were calculated to show the relative likelihood that different drivers under different conditions will commit aggressive behaviors. The rate of aggressive actions observed in this study decreased from the most frequent behavior of cutting across a single lane, through honking, and to the least frequent behaviors of cutting across multiple lanes and passing on the shoulders. Relative to their proportion in the driving population, men were more likely than women to commit aggressive actions, and the differences increased as the severity of the action increased. Drivers who were 45 years old or older were less likely to drive aggressively than younger ones. The presence of passengers was associated with a slight but consistent reduction in aggressive driving of all types; especially honking at other drivers. There was a strong linear association between congestion and the frequency of aggressive behaviors, but it was due to the number of drivers on the road. However, when the value of time was high (as in rush hours), the likelihood of aggressive driving--after adjusting for the number of drivers on the road--was higher than when the value of time was low (during the non-rush weekday or weekend hours). The results have implications for driver behavior modifications and for environmental design.     

Driver rehabilitation: A systematic review of the types and effectiveness of interventions used by occupational therapists to improve on-road fitness-to-drive

Objective

Driver rehabilitation has the potential to improve on-road safety and is commonly recommended to clients. The aim of this systematic review was to identify what intervention approaches are used by occupational therapists as part of driver rehabilitation programmes, and to determine the effectiveness of these interventions.

Method

Six electronic databases (MEDLINE, CINAHL, PsycInfo, Embase, The Cochrane Library, and OTDBase) were searched. Two authors independently reviewed studies reporting all types of research designs and for all patient populations, provided the interventions could be administered by occupational therapists. The methodological quality of studies was assessed using the ‘Downs and Black Instrument’, and the level of evidence for each intervention approach was established using ‘Centre for Evidence Based Medicine’ criteria.

Results

Sixteen studies were included in the review. The most common type of intervention approach used was computer-based driving simulator training (n = 8), followed by off-road skill-specific training (n = 4), and off-road education programmes (n = 3). Car adaptations/modifications were used in one of the included studies. There was significant variability between studies with regards to frequency, duration, and total number of intervention sessions, and the diagnoses of the participants. Of the four intervention approaches, there is evidence to support the effectiveness of off-road skill-specific training (with older clients), and computer-based driving simulator training (with both older clients and participants with acquired brain injury).

Conclusion

Three types of intervention approaches are commonly reported, however, there is limited evidence to determine to effectiveness of these in improving fitness-to-drive. Further research is required, with clients from a range of diagnostic groups to establish evidence-based interventions and determine their effectiveness in improving these clients’ on-road fitness-to-drive.     

Impact of perceptual treatments on lateral control during driving on crest vertical curves: a driving simulator study

Approximately 48% of all fatal collisions in Europe are classified as single-vehicle run-off-road or head-on collisions. These crashes relate to trajectory control (road departure) and represent a safety challenge. In France, single-vehicle run-off-road crashes represent 21% of all crashes and head-on collisions represent 11%. This study evaluated the effectiveness of four perceptual treatments (i.e., a painted center line, post-delineators, rumble strips on both sides of the center line and sealed shoulders) in supporting the driver to maintain lateral control; that is, to support the driver to keep in the center of his/her lane. Forty-three participants drove a fixed-base driving simulator, on a simulated straight 3 km rural road with two crest vertical curves (CVC). Four sections were chosen for analysis: a reference section (i.e., the first CVC), a test section (i.e., the second CVC), a pre-test section (i.e., immediately before the second CVC) and a post-test section (i.e., immediately after the second CVC). The results showed that drivers drive more at the center of their lane with the rumble strips on both sides of the center line and with the sealed shoulders than with the actual marking (here center line) or other treatments.     

Lane heading difference: An innovative model for drowsy driving detection using retrospective analysis around curves

Driving while sleepy is a serious contributor to automobile accidents. Previous research has shown that drowsy drivers produce systematic errors (variability) in vehicle behavior which are detectable using vehicle monitoring technology. The current study developed a new methodological approach using a vehicle heading difference metric to detect drowsy driving more effectively than other more commonly used methods. Twenty participants completed a driving scenario as well as several measures of fatigue in five testing sessions across a night of sleep deprivation. Each simulated highway driving session lasted 20 min, and was analyzed for lateral lane position variability and vehicle heading difference variability with two statistical methods. Fatigue measures monitored reaction time, attention, and oculomotor movement. The results showed that examining lane heading difference using the absolute value of the raw data detected driving variability better across the night than other statistical models. The results from the fatigue measures indicated an increase in reaction time and response lapses, as well as a decrease in oculomotor reactivity across the night. These results suggest that in fatigued drivers the statistical model using the absolute value of lane heading could be an improved metric for drowsy driving detection that could accurately detect detriments in driving ability at lower levels of fatigue.     

Health literacy of older drivers and the importance of health experience for self-regulation of driving behaviour

This study provides much needed information on the education level of older drivers regarding the impact of health conditions and medications on personal driving safety, where they source this information, and how this knowledge influences self-regulation of driving. Random and convenience sampling secured 322 Australian drivers (63.9% males) aged 65 years and over (M = 77.35 years, SD = 7.35) who completed a telephone interview. The majority of respondents (86%) had good knowledge about health conditions (health knowledge) and driving safety, however more than 50% was classified as having poor knowledge on the effects of certain medications (medication knowledge) and driving safety. Poorer health knowledge was associated with a reduced likelihood of driving over 100 km in adjusted models. Being older and having more than one medical condition was found to increase the likelihood of self-regulation of driving. Results indicate that health knowledge was less important for predicting driving behaviour than health experience. Of great interest was that up to 85.7% of respondents reported not receiving advice about the potential impact of their medical condition and driving from their doctor. The findings indicate a need for improved dissemination of evidence-based health information and education for older drivers and their doctors.     

The association between driving anger and driving outcomes: A meta-analysis of evidence from the past twenty years

Through the use of meta-analysis, this study investigated the relationships between driving anger and five types of driving outcomes (aggressive driving, risky driving, driving errors, near misses and accidents). The moderating effects of three variables (age, study publication year, and participants’ country of origin) on these relationships were also examined. A total of 51 studies published over the past two decades met the inclusion criteria for the meta-analysis. The results showed that driving anger significantly predicted all three types of aberrant driving, with zero-order correlations of 0.312, 0.243, and 0.179 with aggressive driving, risky driving and driving errors, respectively. The correlations between driving anger and accident-related conditions, though at relatively weaker levels, were still statistically significant. Tests for effects of the moderating variables suggested that driving anger was a stronger predictor of risky driving among young drivers than among old drivers. Also, the anger–aggression association was found to decrease over time and vary across countries. The implications of the results and the directions for future research are discussed.     

Sharing the responsibility for driver distraction across road transport systems: A systems approach to the management of distracted driving

Distracted driving is acknowledged universally as a large and growing road safety problem. Compounding the problem is that distracted driving is a complex, multifaceted issue influenced by a multitude of factors, organisations and individuals. As such, management of the problem is not straightforward. Numerous countermeasures have been developed and implemented across the globe. The vast majority of these measures have derived from the traditional reductionist, driver-centric approach to distraction and have failed to fully reflect the complex mix of actors and components that give rise to drivers becoming distracted. An alternative approach that is gaining momentum in road safety is the systems approach, which considers all components of the system and their interactions as an integrated whole. In this paper, we review the current knowledge base on driver distraction and argue that the systems approach is not currently being realised in practice. Adopting a more holistic, systems approach to distracted driving will not only improve existing knowledge and interventions from the traditional approach, but will enhance our understanding and management of distraction by considering the complex relationships and interactions of the multiple actors and the myriad sources, enablers and interventions that make up the distracted driving system. It is only by recognising and understanding how all of the system components work together to enable distraction to occur, that we can start to work on solutions to help mitigate the occurrence and consequences of distracted driving.     

Taking a look behind the wheel: An investigation into the personality predictors of aggressive driving

The present study evaluated a theoretical model of the relationships among six aspects of driver personality (i.e., driving anger and the Big Five personality factors), aggressive driving, and two outcomes of aggressive driving: motor vehicle crashes and moving violations. Data from 308 drivers recruited from two vehicle licensing offices were analyzed using structural equation modeling. As expected, aggressive driving predicted crashes and moving violations. Based on the zero-order correlations, emotional stability, agreeableness, and conscientiousness were related to aggressive driving in the expected directions; however, the picture changed when the joint effects of all variables were examined via structural equation modeling. A model in which driver personality predicted aggressive driving, which in turn predicted crashes and moving violations was supported. Drivers who were high on driving anger and low on agreeableness reported driving more aggressively. Implications for traffic safety professionals and researchers are discussed.