A skewed logistic model of two-unit bicycle-vehicle hit-and-run crashes.

OBJECTIVE: Hit-and-run behavior in crashes is a severe offense worldwide because the identification and emergency rescue of any injured road user is delayed. A motorist's run from the crash scene is especially serious for a cyclist who would be more prone to be physically injured in a bicycle-vehicle (BV) crash. The objective of this paper is to explore potential risk factors that contribute to the hit-and-run (HR) behavior of a driver after a two-unit BV collision. METHODS: The data used in this study are extracted from traffic crash records in the city of Durham, North Carolina in 2007-2014. This study uses the skewed logistic (Scobit) model to account for the skewness of the dependent variable (i.e., HR) in the dataset. RESULTS: The Likelihood ratio test, AIC and BIC results show that the Scobit model is preferred to the standard binary logistic model for modeling a driver's decision to run from a two-unit BV crash scene. Estimation results indicate that, the driver's tendency to run from a crash scene without reporting it in Durham increases if the bicyclist is a teenager or an adult, a drunk-driving or a speeding driver is involved, when the crash happens at night (19:00-6:59), on a local street, or when the automobile overtakes the bicycle. HR behavior will decrease if the cyclist is drunk, an SUV is involved, or the bicyclist fails to yield. CONCLUSIONS: The findings of this study are important and useful when developing countermeasures to prevent BV-HR crashes and to improve cycling safety.

Traffic safety meta-analysis of reversible lanes.

A meta-analysis was performed to review the potential effects of reversible lanes on traffic safety. A systematic review resulted in ten U.S studies, with 155 estimates of safety effects, that were selected for inclusion in the analysis. These studies employed either a simple before-after comparison or a cross-sectional comparison methodology. Study results were extracted by transforming the collision rates and frequencies of these studies into a log-odds ratio. The results of the meta-analysis suggest that the odds of a collision occurring are 30.9% higher for roads with reversible lanes when compared to roads without the treatment. The odds of a property-damage-only collision are predicted to be 16.6% higher, and injury collisions are predicted to be 34.9% higher with reversible lanes compared to no-treatment. The odds of a collision occurring during the peak period are expected to be 46.2% higher, while the odds of an off-peak period collision occurring are expected to be 12.8% higher. These results were statistically significant, with the exception of the off-peak period collision result. A meta-regression was performed, which regresses variables related to study type, collision type and operational characteristics of the study locations on the extracted log odds ratio. Peak period operations were positively and significantly correlated with an increase in crashes. Presence of left-turn restrictions and/or delineator/barrier were negatively correlated with crashes, whereas the presence of dynamic traffic control and static traffic control were positively correlated with crashes. Finally, cross sectional studies tend to find greater effects than before-after studies.

A random parameter logistic model of fatigue-related motorcycle crash involvement in Hanoi, Vietnam.

Since motorcycle taxi drivers often work long hours, fatigue would affect their riding abilities, impacting crash risks. However, there is limited understanding about motorcycle taxi drivers' fatigue-related crashes. This study investigates self-reported fatigue-related crashes among motorcycle taxi drivers in Hanoi, Vietnam. Results from a survey showed that approximately 16% of the motorcycle taxi drivers reported fatigue-related crash involvement. It was also found that nearly 37% of all crashes reported by motorcycle taxi drivers were related to fatigue while riding a motorcycle taxi. Results of the heterogeneity-in-means random parameter logistic model suggested that working fulltime, more delivery trips, and overweight conditions were associated with increased likelihoods of fatigue-related crash involvement. Hybrid taxi drivers, who operate as either traditional or ride-hailing taxi drivers at different times, and most ride-hailing taxi drivers had a reduced likelihood of fatigue-related crash involvement when compared to traditional taxi drivers. Overall, this study has revealed a significant issue of fatigue-related crashes among motorcycle taxi drivers. Immediate interventions via publicity or educational campaigns should be considered by authorities to address this important issue. Ride-hailing companies should contribute by sending warnings of excessive riding hours to ride-hailing taxi drivers.

Behaviors of older pedestrians at crosswalks in South Korea.

This paper aims to explore three walking behaviors of older pedestrians that may increase their crash risks when crossing urban streets. Older and younger pedestrians' start-up delay in initiating a crossing and number of head turns during street crossing are observed at 30 pedestrian crossings in Seoul, South Korea, using video recorders. In addition, their estimation of the safe crossing distance to an approaching vehicle is collected in a survey. Our study shows that older pedestrians have a shorter start-up delay time than younger pedestrians, older pedestrians crossing streets turn their heads less frequently, and older pedestrians provide less reliable estimates about the distance of an approaching vehicle. Safety technologies, campaigns and environmental designs should target these behaviors to improve the safety of older pedestrians.

"I'm very visible but seldom seen": consumer choice and use of mobility aids on public transport.

PURPOSE: The number of mobility aid users continues to rise as the population ages. While mobility aid users rely on public transport due to its affordability, evidence suggests access can be difficult. This study aims to describe people who use mobility aids to access public transport and the role of public transport access in influencing mobility aid choice. METHODS: Sixty-seven mobility aid users participated in telephone surveys which predominantly used a structured quantitative format. Data were analysed descriptively and any additional comments were simply categorized. RESULTS: Thirty-six participants were female (54%), with a total sample mean age of 58.15 years (SD = 14.46). Seventy-two percent lived in metropolitan areas, 48% lived alone, and the sample experienced a variety of conditions including spinal cord injury (37%) and arthritis (18%). Sixty-four percent of all respondents used two or more mobility aids including powered wheelchairs, scooters and walking frames. The most important features when choosing a mobility aid were reliability, turning ability and size. Fifty-two percent of all respondents strongly agreed that public transport is generally accessible. CONCLUSIONS: While work continues to ensure that public transport vehicles and stations are fully accessible, mobility aid users must manage current infrastructure and access a system which has been shown through this research to have many limitations. Mobility aid users, vendors and health professionals need to work together to identify mobility aids that fulfil needs, and are reliable and safe, so that mobility aid users are both "visible and seen" when accessing the public transport network. Implications for rehabilitation Some mobility aid users experience difficulties accessing and using public transport and further research is required to ensure the whole public transport network is fully accessible to people using mobility aids. Many people have more than one seated mobility aid, suggesting people can choose different aids for different purposes and environments. Health professionals may need to increase their involvement in assisting individuals to select and use mobility aids.

Influence of pedestrian age and gender on spatial and temporal distribution of pedestrian crashes.

OBJECTIVES: Every year, about 1.24 million people are killed in traffic crashes worldwide and more than 22% of these deaths are pedestrians. Therefore, pedestrian safety has become a significant traffic safety issue worldwide. In order to develop effective and targeted safety programs, the location- and time-specific influences on vehicle-pedestrian crashes must be assessed. The main purpose of this research is to explore the influence of pedestrian age and gender on the temporal and spatial distribution of vehicle-pedestrian crashes to identify the hotspots and hot times. METHODS: Data for all vehicle-pedestrian crashes on public roadways in the Melbourne metropolitan area from 2004 to 2013 are used in this research. Spatial autocorrelation is applied in examining the vehicle-pedestrian crashes in geographic information systems (GIS) to identify any dependency between time and location of these crashes. Spider plots and kernel density estimation (KDE) are then used to determine the temporal and spatial patterns of vehicle-pedestrian crashes for different age groups and genders. RESULTS: Temporal analysis shows that pedestrian age has a significant influence on the temporal distribution of vehicle-pedestrian crashes. Furthermore, men and women have different crash patterns. In addition, results of the spatial analysis shows that areas with high risk of vehicle-pedestrian crashes can vary during different times of the day for different age groups and genders. For example, for those between ages 18 and 65, most vehicle-pedestrian crashes occur in the central business district (CBD) during the day, but between 7:00 p.m. and 6:00 a.m., crashes among this age group occur mostly around hotels, clubs, and bars. CONCLUSIONS: This research reveals that temporal and spatial distributions of vehicle-pedestrian crashes vary for different pedestrian age groups and genders. Therefore, specific safety measures should be in place during high crash times at different locations for different age groups and genders to increase the effectiveness of the countermeasures in preventing and reducing vehicle-pedestrian crashes.

Turning movements, vehicle offsets and ageing drivers driving behaviour at channelized and unchannelized intersections.

Ageing drivers experience a higher risk of intersection crashes because of their decrease in driving efficiency, including the decline in cognitive ability, head and neck flexibility, and visual acuity. Although several studies have been conducted to examine the factors associated with ageing driver crashes at intersections, little research has been conducted to examine the differences in the factors related to ageing drivers' turning paths and intersection geometric features. This study aims to improve the safety of ageing drivers at intersections by identifying the maneuvers that are risky for them and tracking their turning movements at selected intersections. We find that ageing drivers experience more crashes at intersections than younger drivers, especially crashes involving turning movements. Furthermore, ageing drivers experience more crashes at unchannelized intersections compared to channelized intersections. In addition, this study finds that ageing drivers exhibit greater and more inconsistent offsets during turning movements compared to those of younger drivers at both channelized and unchannelized intersections. Ageing drivers also tend to make relatively sharper or tighter turns than younger drivers. Hence, transportation engineers and road safety professionals should consider appropriate countermeasures to reduce the risks of crashes involving ageing drivers at intersections.

Neighborhood Influences on Vehicle-Pedestrian Crash Severity.

Socioeconomic factors are known to be contributing factors for vehicle-pedestrian crashes. Although several studies have examined the socioeconomic factors related to the location of the crashes, limited studies have considered the socioeconomic factors of the neighborhood where the road users live in vehicle-pedestrian crash modelling. This research aims to identify the socioeconomic factors related to both the neighborhoods where the road users live and where crashes occur that have an influence on vehicle-pedestrian crash severity. Data on vehicle-pedestrian crashes that occurred at mid-blocks in Melbourne, Australia, was analyzed. Neighborhood factors associated with road users' residents and location of crash were investigated using boosted regression tree (BRT). Furthermore, partial dependence plots were applied to illustrate the interactions between these factors. We found that socioeconomic factors accounted for 60% of the 20 top contributing factors to vehicle-pedestrian crashes. This research reveals that socioeconomic factors of the neighborhoods where the road users live and where the crashes occur are important in determining the severity of the crashes, with the former having a greater influence. Hence, road safety countermeasures, especially those focussing on the road users, should be targeted at these high-risk neighborhoods.

Factors associated with crashes involving taxi owners and non-owners: A case of moral hazard and adverse selection?

Taxis experience a higher risk of a motor vehicle crash partly because of their much higher levels of exposure on the roads. Although several studies have been conducted to examine the factors associated with the frequency and severity of taxi collisions, little research has been conducted to examine the differences in the factors associated with owner taxis and non-owner taxis. This study finds that collisions involving non-owners are more likely to be associated with poor or risky driving behaviors than collisions involving taxi vehicle owners. This result is consistent with the economic principles of moral hazard and adverse selection. Hence, policy makers responsible for traffic safety, taxi regulation or taxi operations should consider measures to reduce these market inefficiencies and improve the safety of not only taxi drivers but all road users.

Comparison of the binary logistic and skewed logistic (Scobit) models of injury severity in motor vehicle collisions.

The binary logistic model has been extensively used to analyze traffic collision and injury data where the outcome of interest has two categories. However, the assumption of a symmetric distribution may not be a desirable property in some cases, especially when there is a significant imbalance in the two categories of outcome. This study compares the standard binary logistic model with the skewed logistic model in two cases in which the symmetry assumption is violated in one but not the other case. The differences in the estimates, and thus the marginal effects obtained, are significant when the assumption of symmetry is violated.

A random parameters probit model of urban and rural intersection crashes.

Intersections are hazardous locations and many studies have been conducted to identify the factors contributing to the frequency and severity of intersection crashes. However, little attention has been devoted to investigating the differences between crashes at urban and rural intersections, which have different road, traffic and environmental characteristics. By applying a random parameters probit model to the data from the Canadian Province of Alberta between 2008 and 2012, we find that urban intersection crashes are more likely to be associated with hit and run behaviours, roads with higher traffic volume, wet surfaces, four lanes and skewed intersections, and crashes on weekdays and off-peak hours, whereas rural crashes are likely to be associated with increases in fatalities and injuries, roads with higher speed limits, special road features, exit and entrance terminals, gravel, curvature and two lanes, crashes during weekends, peak hours and night-time, run-off-road crashes, and police visit to crash scene. Hence, road safety professionals in urban and rural areas should consider these differences when designing and implementing counter-measures to improve intersection safety, especially their safety audits and reviews, enforcement activities and education campaigns, to target the more vulnerable times and locations in the different areas.

Development and validation of the Occupational Therapy Risk Propensity Test (OT-RiPT) for drivers with disability.

BACKGROUND: Male drivers in the 16- to 19-year age group have a nine-fold increase in their crash risk compared with 25- to 34-year-olds who have a relative risk of 2.3. Crash risk in young drivers has been directly linked to risk-taking behaviour. This paper reports the development of a video risk assessment tool for use with drivers. AIM/OBJECTIVE: This paper reports on the process of validating and investigating the reliability of the Occupational Therapy Risk Propensity Test (OT-RiPT) to measure risk-taking propensity. MATERIAL AND METHODS: 20 healthy male participants were recruited. OT-RiPT scores were correlated with driving experience. Internal consistency was investigated using Cronbach's alpha. Face validity was established. The OT-RiPT and a validated driver behaviour questionnaire were administered and the results correlated to establish discriminant validity. RESULTS: There was no significant correlation between driving experience and OT-RiPT scores. Good internal consistency was established. OT-RiPT has high face validity. Discriminant validity was demonstrated. CONCLUSION AND SIGNIFICANCE: Pending further testing, OT-RiPT shows promise as a reliable and valid measure of risk-taking propensity in young drivers.

Examining driver injury severity in two vehicle crashes - a copula based approach.

A most commonly identified exogenous factor that significantly affects traffic crash injury severity sustained is the collision type variable. Most studies consider collision type only as an explanatory variable in modeling injury. However, it is possible that each collision type has a fundamentally distinct effect on injury severity sustained in the crash. In this paper, we examine the hypothesis that collision type fundamentally alters the injury severity pattern under consideration. Toward this end, we propose a joint modeling framework to study collision type and injury severity sustained as two dimensions of the severity process. We employ a copula based joint framework that ties the collision type (represented as a multinomial logit model) and injury severity (represented as an ordered logit model) through a closed form flexible dependency structure to study the injury severity process. The proposed approach also accommodates the potential heterogeneity (across drivers) in the dependency structure. Further, the study incorporates collision type as a vehicle-level, as opposed to a crash-level variable as hitherto assumed in earlier research, while also examining the impact of a comprehensive set of exogenous factors on driver injury severity. The proposed modeling system is estimated using collision data from the province of Victoria, Australia for the years 2006 through 2010.

Improving drivers' knowledge of road rules using digital games.

Although a proficient knowledge of the road rules is important to safe driving, many drivers do not retain the knowledge acquired after they have obtained their licenses. Hence, more innovative and appealing methods are needed to improve drivers' knowledge of the road rules. This study examines the effect of game based learning on drivers' knowledge acquisition and retention. We find that playing an entertaining game that is designed to impart knowledge of the road rules not only improves players' knowledge but also helps them retain such knowledge. Hence, learning by gaming appears to be a promising learning approach for driver education.

Comparison of crashes during public holidays and regular weekends.

Traffic collisions and fatalities during the holiday festive periods are apparently on the rise in Alberta, Canada, despite the enhanced enforcement and publicity campaigns conducted during these periods. Using data from 2004 to 2008, this research identifies the factors that delineate between crashes that occur during public holidays and those occurring during normal weekends. We find that fatal and injury crashes are over-represented during holidays. Amongst the three risky behaviors targeted in the holiday blitzes (driver intoxication, unsafe speeding and restraint use), non-use of restraint is more prevalent whereas driver intoxication and unsafe speeding are less prevalent during holidays. The mixed results obtained suggest that it may be time to consider a more balanced approach to the enhanced enforcement and publicity campaigns.

Severity of motorcycle crashes in Calgary.

Motorcycle riders would be more vulnerable in the event of a crash because of their lack of protection which would often result in them suffering more severe injuries than car drivers. This paper estimated three crash severity models to identify factors that contributed to increasing the severity of motorcycle involved crashes in the Canadian City of Calgary. We found that results from the ordered logit model, heterogeneous choice model and partially constrained generalized ordered logit model produced estimates that were very similar which attested to their robustness. Injury severity tended to increase in neighborhoods with loops and lollipops types of streets or involved right-angle and left-turn-across-path crashes, a truck, unsafe speed or alcohol use but tended to decrease if the crash occurred in parking lots or during winter, involved a van or male rider, or a rider following-too-closely to the vehicle in front.

Managing speed at school and playground zones.

Since speeding is one of the major causes of frequent and severe traffic accidents around school and playground areas, many jurisdictions have reduced the speed limits in these areas to protect children who may be at risk. This paper investigated the speed compliance, mean speed and 85th percentile speed at selected school and playground zones in the City of Calgary in Alberta. Our results showed that the mean speed was lower and the rate of compliance was higher in the school zone compared to the playground zone, 2 lane roads relative to 4 lane roads, roads with fencing, traffic control devices and the presence of speed display device or children, and zones that were longer (> 200 m). Accordingly, this study provided recommendations to improve the effectiveness of school and playground zone speed limits.

Should traffic enforcement be unpredictable? The case of red light cameras in Edmonton.

Red light cameras are installed in many jurisdictions around the world to improve road safety by discouraging red light running behaviour at signalized intersections. In many jurisdictions, a smaller number of cameras are rotated among a larger number of locations to increase the effectiveness of the red light camera programs. This study outlines some arguments for deciding the best deployment strategy that can be used to rotate these cameras, focusing on the deterrent effects of enforcement and punishment on driver behaviour. A simple on-road experiment is then conducted to determine the effectiveness of three different rotation schemes. Our results suggest that not moving the cameras and keeping enforcement predictable yields a lower average violation rate than moving the cameras around and making enforcement uncertain.

Effect of street pattern on the severity of crashes involving vulnerable road users.

Road crashes not only claim lives and inflict injuries but also create an economic burden to the society due to loss of productivity. Although numerous studies have been conducted to examine a multitude of factors contributing to the frequency and severity of crashes, very few studies have examined the influence of street pattern at a community level. This study examined the effect of different street patterns on crash severity using the City of Calgary as a case study. In this study, street pattern is classified into four categories: grid-iron, warped parallel, loops and lollipops, and mixed patterns. Their effects on injury risk are examined together with other factors including road features, drivers' characteristics, crash characteristics, environmental conditions and vehicle attributes. Pedestrian and bicycle crash data for the years 2003-2005 were utilized to develop a multinomial logit model of crash severity. Our results showed that compared to other street patterns, loops and lollipops design increases the probability of an injury but reduces the probability of fatality and property-damage-only in an event of a crash.

Effects of roadside memorials on traffic flow.

Despite their growing popularity in North America, little research has been conducted on understanding the effects of roadside memorials on drivers' behaviour. In this study, we examined the short-term effects of roadside memorials on traffic speed and headways on a high speed intercity freeway as well as its long-term effect on traffic speed on a high speed urban freeway. Our study found that the placement of roadside memorials did not have any significant effect on traffic speeds or headways, either in the short or long term. Therefore, concerns about the negative effects on driver behaviour were not supported by this research, at least with regards to speeding and following too closely. However, no positive effects on safety were found either.