Drivers with child passengers: distracted but cautious?

OBJECTIVE: A remarkable portion of children's traffic-related deaths occurred when travelling in as passengers in vehicles, but so far, few studies have focused on crash characteristics and crash risks of drivers with child passengers. It has been assumed that drivers with child passengers drive responsibly, but on the contrary, children in vehicles can distract drivers, increasing crash risks. In this study, we examined fatal crash characteristics and fatal crash risks of drivers with child passengers. METHODS: Fatal crash data from the U.S. Fatality Analysis Reporting System (FARS) for 1996-2015 were used. Only passenger-vehicle drivers aged 23-46 years old were included in the analysis because they represent the typical age of drivers with 0-9-year-old child passengers in the database. Prevalence of crash characteristics and the odds of being at fault were examined for drivers with only child passengers and compared to drivers with only adult passengers, with no passengers and with both adult and child passengers. Analyses were done separately for intersection crashes and non-junction crashes. RESULTS: Female drivers were involved in twice as many fatal crashes alone with child passengers compared to male drivers. Drivers with only child passengers were more often reported as being inattentive, but for them, risk-taking behaviours were less typical than for drivers without child passengers. Our results showed that these differences were more evident in non-junction crashes than in intersection crashes. When risk-taking behaviours were controlled, both male and female drivers with only child passengers had higher odds of being at fault than drivers with adult passengers (with or without children) in non-junction crashes, but these differences were not significant in intersection crashes. CONCLUSIONS: Drivers with child passengers represent a specific driver population. They have a higher tendency to engage in distractions while driving, but they have fewer risk-taking behaviour-related fatal crashes compared to drivers with no child passengers. Our results indicate that the effects of child-passenger-related distractions on fatal crash risks are more relevant outside intersections, presumably because drivers may try to self-regulate their interactions with child passengers and focus on driving in more demanding traffic situations.

Expert evaluation of traffic signs: conventional vs. alternative designs.

Traffic sign comprehension is significantly affected by their compliance with ergonomics design principles. Despite the UN Convention, designs vary among countries. The goal of this study was to establish theoretical and methodological bases for evaluating the design of conventional and alternative signs. Thirty-one conventional signs and 1-3 alternatives for each conventional sign were evaluated for their compliance with three ergonomics guidelines for sign design: physical and conceptual compatibility, familiarity and standardisation. Twenty-seven human factors and ergonomics experts from 10 countries evaluated the signs relative to their compliance with the guidelines. Analysis of variance across alternatives revealed that for 19 of the 31 signs, an alternative design received a significantly higher rating in its ergonomics design than the conventional sign with the same meaning. We also found a very high correlation between the experts' ratings and comprehension from previous studies. In conclusion, many countries use signs for which better alternative designs exist, and therefore UN Convention signs should be re-examined, and ergonomics experts evaluation can serve as a good surrogate for road users' comprehension surveys. Practitioner summary: This study presents theoretical and methodological bases for evaluating the design of UN Conventional and alternative traffic signs. Human factors and ergonomics experts evaluated 31 conventional and 68 alternative road signs, based on ergonomics principles for sign design. Results indicated the need to re-examine poorly designed UN Convention signs.

Gaze doesn't always lead steering.

In car driving, gaze typically leads the steering when negotiating curves. The aim of the current study was to investigate whether drivers also use this gaze-leads-steering strategy when time-sharing between driving and a visual secondary task. Fourteen participants drove an instrumented car along a motorway while performing a secondary task: looking at a specified visual target as long and as much as they felt it was safe to do so. They made six trips, and in each trip the target was at a different location relative to the road ahead. They were free to glance back at the road at any time. Gaze behaviour was measured with an eye tracker, and steering corrections were recorded from the vehicle's CAN bus. Both in-car 'Fixation' targets and outside 'Pursuit' targets were used. Drivers often used a gaze-leads-steering strategy, glancing at the road ahead 200-600 ms before executing steering corrections. However, when the targets were less eccentric (requiring a smaller change in glance direction relative to the road ahead), the reverse strategy, in which glances to the road ahead followed steering corrections with 0-400 ms latency, was clearly present. The observed use of strategies can be interpreted in terms of predictive processing: The gaze-leads-steering strategy is driven by the need to update the visual information and is therefore modulated by the quality/quantity of peripheral information. Implications for steering models are discussed.

A computational model for driver's cognitive state, visual perception and intermittent attention in a distracted car following task.

We present a computational model of intermittent visual sampling and locomotor control in a simple yet representative task of a car driver following another vehicle. The model has a number of features that take it beyond the current state of the art in modelling natural tasks, and driving in particular. First, unlike most control theoretical models in vision science and engineering-where control is directly based on observable (optical) variables-actions are based on a temporally enduring internal representation. Second, unlike the more sophisticated engineering driver models based on internal representations, our model explicitly aims to be psychologically plausible, in particular in modelling perceptual processes and their limitations. Third, unlike most psychological models, it is implemented as an actual simulation model capable of full task performance (visual sampling and longitudinal control). The model is developed and validated using a dataset from a simplified car-following experiment (N = 40, in both three-dimensional virtual reality and a real instrumented vehicle). The results replicate our previously reported connection between time headway and visual attention. The model reproduces this connection and predicts that it emerges from control of action uncertainty. Implications for traffic psychological models and future developments for psychologically plausible yet computationally rigorous models of full natural task performance are discussed.

Trade-off between jerk and time headway as an indicator of driving style.

Variation in longitudinal control in driving has been discussed in both traffic psychology and transportation engineering. Traffic psychologists have concerned themselves with "driving style", a habitual form of behavior marked by it's stability, and its basis in psychological traits. Those working in traffic microsimulation have searched for quantitative ways to represent different driver-car systems in car following models. There has been unfortunately little overlap or theoretical consistency between these literatures. Here, we investigated relationships between directly observable measures (time headway, acceleration and jerk) in a simulated driving task where the driving context, vehicle and environment were controlled. We found individual differences in the way a trade-off was made between close but jerky vs. far and smooth following behavior. We call these "intensive" and "calm" driving, and suggest this trade-off can serve as an indicator of a possible latent factor underlying driving style. We posit that pursuing such latent factors for driving style may have implications for modelling driver heterogeneity across various domains in traffic simulation.

Young females at risk while driving with a small child.

INTRODUCTION: Previous research suggests that young mothers with little driving experience are at risk when driving with a small child passenger. In this study we examined the prevalence, characteristics and risk of fatal motor vehicle crashes involving an infant passenger under the age of one among female drivers of different ages. METHODS: We used crash data from the US Fatality Analysis Reporting System for 1994-2013. The prevalence of fatal crashes involving infants was examined by age of female drivers and compared to the number of births among mothers of a similar age. The essential characteristics of the crashes were described, and the odds of being at fault were determined for young (16-24-year-olds) and older female drivers (25-39-year-olds) with an infant passenger or with no passengers. RESULTS: The prevalence of fatal crashes involving infant passengers was higher among young female drivers in relation to the number of births among mothers of a similar age than among older females. Young female drivers with an infant passenger were more often at fault than older drivers (aOR=1.83, 95%, CI=1.52, 2.20). Their vehicles were older and smaller and they used proper safety seats for infants less often than the older drivers. In addition, young female drivers with an infant passenger but with no adult passenger in the vehicle were more often at fault than young female drivers with no passengers (aOR=1.27, 95% CI=1.06, 1.51). Both young and older female drivers' crashes involving an infant passenger typically occurred in ordinary driving conditions, but these drivers with infant passengers were more often reported as having fallen asleep or inattentive than those with no passengers. The presence of an adult passenger in addition to an infant passenger lowered female drivers' odds of being at fault, regardless of the driver's age. CONCLUSIONS: Young females driving with an infant passenger, probably most often mothers, are at an elevated risk of a fatal crash, especially when they drive alone with an infant. The protective effect of an adult passenger suggests that another adult in the vehicle can assist the driver by taking care of the infant and enabling the driver to focus on driving.

Task-Difficulty Homeostasis in Car Following Models: Experimental Validation Using Self-Paced Visual Occlusion.

Car following (CF) models used in traffic engineering are often criticized for not incorporating "human factors" well known to affect driving. Some recent work has addressed this by augmenting the CF models with the Task-Capability Interface (TCI) model, by dynamically changing driving parameters as function of driver capability. We examined assumptions of these models experimentally using a self-paced visual occlusion paradigm in a simulated car following task. The results show strong, approximately one-to-one, correspondence between occlusion duration and increase in time headway. The correspondence was found between subjects and within subjects, on aggregate and individual sample level. The long time scale aggregate results support TCI-CF models that assume a linear increase in time headway in response to increased distraction. The short time scale individual sample level results suggest that drivers also adapt their visual sampling in response to transient changes in time headway, a mechanism which isn't incorporated in the current models.

Learning game for training child bicyclists' situation awareness.

Encouraging more children to bicycle would produce both environmental and health benefits, but bicycling accidents are a major source of injuries and fatalities among children. One reason for this may be children's less developed hazard perception skills. We assume that children's situation awareness could be trained with a computer based learning game, which should also improve their hazard perception skills. In this paper, we present a prototype for such a game and pilot it with 8-9year old children. The game consisted of videos filmed from a bicyclist's perspective. Using a touchscreen, the player's task was to point out targets early enough to gain points. The targets were either overt (other visible road users on a potentially conflicting course) or covert (occlusions, i.e. locations where other road users could suddenly emerge). If a target was missed or identified too late, the video was paused and feedback was given. The game was tested with 49 children from the 2nd grade of primary school (aged 8-9). 31 young adults (aged 22-34) played the game for comparison. The effect of the game on situation awareness was assessed with situation awareness tests in a crossover design. Similar videos were used in the tests as in the game, but instead of pointing out the targets while watching, the video was suddenly masked and participants were asked to locate all targets which had been present just before the masking, choosing among several possible locations. Their performance was analyzed using Signal Detection Theory and answer latencies. The game decreased answer latency and marginally changed response bias in a less conservative direction for both children and adults, but it did not significantly increase sensitivity for targets. Adults performed better in the tests and in the game, and it was possible to satisfactorily predict group membership based on the scores. Children found it especially difficult to find covert targets. Overall, the described version of the learning game cannot be regarded as an effective tool for situation awareness/hazard perception training, but ways to improve the game are discussed.

A study of the effect of OHSAS 18001 on the occupational injury rate in Iran.

The occupational health and safety management system (OHSMS) has been a widely used approach for managing occupational health and safety more effectively worldwide. Despite the interest of organizations in implementing OHSMS in recent decades, few studies have examined the effectiveness of these interventions. This study presents an empirical investigation of the effect of occupational health and safety assessment series (OHSAS) 18001 as a worldwide-accepted OHSMS on the occupational injury rate (OIR) in Iran. This study was carried out in six companies: three OHSAS 18001-certified, and three non-certified, including 998 occupational injuries for 15,842 person-months. A before-after analysis showed a positive safety performance change in one out of the three certified companies. For all 66 study years in the six companies, a negative binomial regression did not indicate a lower occupational injury during the certified years and a repeated measures analysis of variance (ANOVA) did not confirm the effect of certification. The results of this study indicated that the implementation of OHSAS 18001 is not a guarantee of improved safety.

Child passengers and driver culpability in fatal crashes by driver gender.

OBJECTIVE: Studies based on accident statistics generally suggest that the presence of a passenger reduces adult drivers' accident risk. However, passengers have been reported to be a source of distraction in a remarkable portion of distraction-related crashes. Although the effect of passengers on driving performance has been studied extensively, few studies have focused on how a child passenger affects the driver. A child in a car is a potential distractor for parents, especially for mothers of small children, who often suffer from sleep deficit. The aim of this study was to examine how the presence of child passengers of different ages is associated with a higher driver culpability, which was expected due to child-related distraction and fatigue. METHODS: The analysis was based on the comprehensive data of fatal crashes studied in-depth by multidisciplinary road accident investigation teams in Finland during 1988-2012. Teams determine the primary party who had the most crucial effect on the origin of the event. We define the primary party as culpable and the others involved as nonculpable drivers. The culpability rate was defined as the percentage of culpable drivers and rates were compared for drivers with a child/teen passenger aged 0-17 years (N = 348), with an adult passenger without children (N = 324), and when driving alone (N = 579), grouped by child age and driver gender. Drivers with specific risk-related behavior (substantial speeding, driving when intoxicated, unbelted, or without a license) were excluded from the analyses, in order to make the drivers with and without children comparable. Only drivers 26-47 years old were included, representing parents with children 0-9 years of age. RESULTS: Male drivers were less often culpable with 0- to 17-year-old passengers in the car than alone or with adults. This was not the case with female drivers. The gender difference in culpability was most marked with small children age 0-4 years. Female drivers' culpability rate with a 0- to 4-year-old child passenger was higher and male drivers' culpability rate was lower compared to drivers without passengers or with only adult passengers. CONCLUSION: The results indicate that female drivers are at higher risk of crashes than male drivers when driving with small children. Further research is needed to replicate this finding and to determine causal mechanisms.

Measurement invariance of the Driver Behavior Questionnaire across samples of young drivers from Finland and Ireland.

This article investigates the factor structure of the 27-item Driver Behavior Questionnaire (DBQ) in two samples of young drivers (18-25 years of age); one from Finland and the other from Ireland. We compare the two-, three-, and four-factor solutions using Confirmatory Factor Analysis (CFA) and show that the four-factor model (with the latent variables rule violations, aggressive violations, slips and lapses) fits the data from the two countries best. Next, we compare the fit of this model across samples by the means of a measurement invariance analysis in the CFA framework. The analysis shows that the four-factor model fails to fit both samples equally well. This is mainly because the socially-oriented latent variables (rule violations and aggressive violations) are different in nature in the two samples. The cognitively-oriented latent variables (slips and lapses) are, however, similar across countries and the mean values of slips can be compared using latent variable models. However, the common practice of calculating sum scores to represent the four latent DBQ variables and comparing them across subgroups of respondents is unfounded, at least when comparing young respondents from Finland and Ireland.

Risky driving and recorded driving offences: a 24-year follow-up study.

Permanent individual differences in driver behavior and accident risk have long been under active debate. Cognitive and personality factors have correlated with risky driving indicators in cross-sectional studies, and prospective cohort studies are now increasingly revealing early antecedents of risky behavior and injury mortality in adult age, with connections to stable personality traits. However, long-term stability in driver behavior or accident involvement has not been documented in a general driver population.This study reports 24-year follow-up data from a study that compared the recorded offenses between 134 drivers stopped by the police because of sustained risky driving and 121 control drivers stopped at the same locations at the same time in 1987 (Rajalin, 1994. Accid. Anal. Prev., 26, 555-562). Data were compiled from national driver records and accident statistics for the same drivers again 24 years later, and their yearly mileage and speed behavior was requested in a mail survey. The results showed that the two groups of drivers sampled on one trip a quarter of a century ago still differ from each other. The offenders still have more entries in their driver record, also when adjusted for age and mileage (OR=1.59, CI=1.03-2.46), they still report in the survey that they drive faster and overtake other cars more often. The results show that individual differences in driver behavior persist for decades, perhaps for life. However, in this on-road sample, the effect seems to be moderated by occupation which also presumably explains the lower mortality among the offenders during this 24-year follow-up.

Effect of driving experience on anticipatory look-ahead fixations in real curve driving.

Anticipatory skills are a potential factor for novice drivers' curve accidents. Behavioural data show that steering and speed regulation are affected by forward planning of the trajectory. When approaching a curve, the relevant visual information for online steering control and for planning is located at different eccentricities, creating a need to disengage the gaze from the guidance of steering to anticipatory look-ahead fixations over curves. With experience, peripheral vision can be increasingly used in the visual guidance of steering. This could leave experienced drivers more gaze time to invest on look-ahead fixations over curves, facilitating the trajectory planning. Eighteen drivers (nine novices, nine experienced) drove an instrumented vehicle on a rural road four times in both directions. Their eye movements were analyzed in six curves. The trajectory of the car was modelled and divided to approach, entry and exit phases. Experienced drivers spent less time on the road-ahead and more time on the look-ahead fixations over the curves. Look-ahead fixations were also more common in the approach than in the entry phase of the curve. The results suggest that with experience drivers allocate greater part of their visual attention to trajectory planning.

Look-ahead fixations in curve driving.

Two functionally distinct types of fixation, guiding fixations and look-ahead fixations, have been identified in naturalistic tasks based on their temporal relationship to the task execution. In car driving, steering through a curve is guided by fixations toward a region located 1-2 s in the future, but drivers also make fixations further along the road. We recorded drivers' eye movements while they drove an instrumented vehicle on curved rural roads and developed a method to quantify lead time and distance of look-ahead fixations. We also investigated the effect of cognitive load on look-ahead fixations. The look-ahead fixations appear to have a pattern which is connected to the sequential structure of a curve. This suggests that they have a role both in advance planning of the driving line and in the anticipation of oncoming vehicles. Cognitive load led to a shorter look-ahead lead time and distance. PRACTITIONER SUMMARY: We developed a method to quantify lead time and distance of look-ahead fixations in curve driving from on-road eye movement data. The results are relevant for driver modelling and development of anticipation training programmes for novice drivers.

Injuries caused by work-related violence: frequency, need for medical treatment and associations with adverse mental health and alcohol use among Finnish police officers.

BACKGROUND: We examined the associations of the frequency and the need for medical treatment caused by work-related violence with adverse mental health among Finnish police officers (n = 1,734). METHODS: The data were collected via a questionnaire. RESULTS: Employees who had suffered more than one injury were at a 4.86-fold risk (95% CI = 2.72-8.66) of increased alcohol consumption, a 4.40-fold risk (95% CI = 2.87-6.76) of psychological distress symptoms, and a 2.49-fold risk (95% CI = 1.73-3.59) of fear of future violence compared to those who had suffered no injuries. Among those who had suffered injuries (n = 843), the need for medical treatment when injured was associated with a 2.33-fold risk (95% CI = 1.19-4.57) of psychological distress symptoms and with a 2.09-fold risk (95% CI = 1.08-4.03) of fear of future violence when compared to those who did not need medical care for their injury. CONCLUSIONS: Among police officers, high frequency and the need for medical treatment of injuries is associated with an increased risk of adverse mental health. High frequency of injuries may also increase alcohol consumption among police officers.

Work-related violence against security guards--who is most at risk?

Studies on violence in the work of security guards are largely lacking. This study is unique in that it focuses on security guards (n=1,010) in Finland, and assesses the different forms, prevalence, and risk factors of the work-related violence they often face. Information to a survey instrument was obtained by first interviewing 30 volunteers. Then we made a cross-sectional mailed survey that was sent to a randomized group of 2,000 security guards. The response rate was 52. We found the prevalence of verbal aggression, threats of assault, and physical acts against security guards at least once a month to be 39%, 19%, and 15% respectively. As regards risk factors and who is most at risk, our results show that male gender, young age, low work experience, late working hours, and time pressure were associated with all three forms of work-related violence. Unlike other forms of violence, verbal aggression was highly prevalent outside the metropolitan area and directed towards both more and less experienced security guards. In prevention policies for violence, it is important to identify high-risk groups such as those who have less work experience.

Symmetric relationship between self and others in aggressive driving across gender and countries.

OBJECTIVE: It was hypothesized that the combination of self-reported aggressive behaviors committed by the driver himself/herself ("self" scale) and perceiving himself/herself as an object of other drivers' aggressive acts ("other" scale) increases road accident involvement risk across gender and countries. The aim of this study was, therefore, to investigate this symmetric relationship between aggressive driving of self and other and its relationship on accident involvement among British, Dutch, Finnish, and Turkish drivers. METHODS: Survey studies of 3673 drivers were carried out in four countries; that is in Finland, Great Britain, The Netherlands, and Turkey. Analyses were conducted separately for men and women. RESULTS: Overall, the interaction among aggressive warnings, hostile aggression, and revenge factors indicated that aggressive warnings might have a potential to release anger and escalate aggression both "within drivers" and "between drivers." Symmetric interpersonal aggression between aggressive warnings and hostile aggression and revenge factors of self and others created a serious risk for road accident involvement in every country except among British male and Finnish female drivers. CONCLUSIONS: The other driver's aggressive behavior is significantly associated with increased accidents, except for Turkish male drivers. It seems that another driver's aggressive behavior can be important in predicting crashes-even more important than aggressive behavior on the part of the driver him- or herself.

With power comes responsibility: motorcycle engine power and power-to-weight ratio in relation to accident risk.

OBJECTIVE: Current European legislation allows the EU member states to restrict the maximum power output of motorcycles to 74 kW even though evidence supporting the limit is scarce and has produced mixed results-perhaps because motorcycle performance has been measured by engine displacement, not engine power, in most of the previous studies. This study investigates the relationship of motorcycle engine power and power-to-weight ratio to risk of fatal and nonfatal crashes in Finland. METHODS: The fatality rate (number of fatal accidents/number of registered motorbikes) for riders of different ages riding bikes belonging to different power and power-to-weight ratio classes was examined using a comprehensive in-depth database. Data on nonfatal accidents were acquired from a Web questionnaire (N = 2708), which also served as a basis for estimating riders' annual mileage. Mileage data allowed the calculation of accident risk per kilometer ridden for bikes differing in power and power-to-weight ratio. RESULTS: The fatality risk per number of registered motorcycles and per kilometer ridden increases both with power and power-to-weight ratio, independently of rider's age. No relationship between performance and risk of a less severe crash was found. The pre-accident speed of the most powerful bikes was 20 km/h or more over the speed limit in a large proportion of the fatal accidents (odds ratio = 4.8 for > 75 kW motorbikes; odds ratio = 6.2 for > 0.3 kW/kg motorbikes). CONCLUSION: The risk of being involved in a fatal crash is higher among the riders of powerful motorcycles. However, it is not clear whether the results are related to the riding habits of the riders that choose the most powerful bikes available or whether the high risk is due to the properties of the bikes themselves. Therefore, further research is needed before considering legal limits on motorcycle performance.

Fell asleep and caused a fatal head-on crash? A case study of multidisciplinary in-depth analysis vs. the court.

OBJECTIVES: Recognizing road accidents as sleep/fatigue-related is a challenging task due to the lack of validated criteria and reliable devices (cf. breath analyzer for alcohol levels). Consequently, it is difficult to incorporate fatigue in operationalized terms into either traffic or criminal law. Finnish Road Traffic Act explicitly forbids driving while tired but only on a general level regarding the driver's fitness to drive. The aim was to explore and compare the discussions held and conclusions reached by multidisciplinary accident-investigation teams and Finnish courts. METHODS: We describe nine fatal head-on crashes in which, according to the multidisciplinary investigation teams, the guilty nonintoxicated surviving driver had fallen asleep and caused the death of an occupant in the other vehicle. RESULTS: Despite the obvious difficulties with the data collection, the investigation teams provided sufficient information and explanation as to why falling asleep was the most probable cause of these nine accidents. On the other hand, there was wide variation in the court discussions and decisions. The court extensively deliberated on the role of fatigue in the four cases and only one driver was charged under the article of the Road Traffic Act covering driver fatigue. CONCLUSIONS: In conclusion, this study illustrates difficulties in enforcing the law that forbids driving while tired. Although multidisciplinary investigation teams analyze fatal accidents for safety-research purposes, and have a wider degree of freedom when making their conclusions, we believe that such expert evidence would be beneficial to the courts when they consider similar cases.

Fatal road accidents among Finnish military conscripts: fatigue-impaired driving.

The aims of the present study were to determine the current prevalence of personal car usage for holiday trips among Finnish conscripts and to analyze conscripts' fatal road accidents. The data included questionnaire data collected from 259 young conscripts at a garrison in southeastern Finland and data on 46 fatal road accidents caused by conscripts during the years 1991-2004, extracted from the national database of fatal road accidents studied in depth. The questionnaire data showed that one-third (35.9%) of young Finnish conscripts had used personal cars to travel to or from the garrison in the preceding 2 months. More than one-half of them reported driving while fatigued (a majority reported several occasions of such driving). In addition to those driving themselves, 41.6% of the conscripts rode at least occasionally as a passenger in a car driven by a fellow conscript. Analysis of the fatality data showed that one-half of the conscripts' fatal accidents occurred on the way to or from the garrison or while on duty. Falling asleep was the main cause of all conscripts' accidents (34.8%), with the largest proportion occurring when departing for leave (42.9%). Haste (including speeding) was the second greatest factor contributing to accidents occurring on the way to or from the garrison (26.1%), whereas drunk driving (22.7%) and suspected suicides (18.2%) were typical of accidents occurring on leave.