The effect of cycle lanes on the proximity between motor traffic and cycle traffic

An experiment collected proximity data of motor traffic overtaking cycle traffic on roads with and without cycle lanes using an instrumented bicycle. The work enhances previous research which has considered the riding position of the cyclist and whether or not the cyclist was helmeted, while controlling for vehicle type.The analysis shows that significantly wider passing distances are adopted by motorists in the condition without a 1.45 m cycle lane, with posted speed limits of 40 mph and 50 mph with a 9.5 m wide carriageway. These findings were not replicated for a similar width road with a posted speed limit of 30 mph and a 1.3 m cycle lane.The results suggest that in the presence of a cycle lane, drivers may be driving within the confines of their own marked lane with less recognition being given to the need to provide a comfortable passing distance to cycle traffic in the adjacent cycle lane.     

Motorcyclists’ speed and “looked-but-failed-to-see” accidents

Previous research on motorcycle crashes has shown the frequency and severity of accidents in which a non-priority road user failed to give way to an approaching motorcyclist without seeing him/her, even though the road user had looked in the approaching motorcycle's direction and the motorcycle was visible. These accidents are usually called “looked-but-failed-to-see” (LBFS) accidents. This article deals with the effects that the motorcyclist's speed has in these accidents. It is based on the in-depth study and precise kinematic reconstruction of 44 accident cases involving a motorcyclist and another road user, all occurring in intersections. The results show that, in urban environments, the initial speeds of motorcyclists involved in “looked-but-failed-to-see” accidents are significantly higher than in other accidents at intersections. In rural environments, the difference in speed between LBFS accidents and other accidents is not significant, but further investigations would be necessary to draw any conclusions. These results suggest that speed management, through road design or by other means, could contribute to preventing “looked-but-failed-to-see” motorcycle accidents, at least in urban environments.     

Cyclists' perception of risk in roundabouts

Converting an intersection into a roundabout improves motor vehicle safety, but a similar safety effect is not found for car–bicycle collisions. Very little is known about the reasons behind these collisions. In this study a first step towards an understanding of the reasons behind these collisions is taken. The study focuses on cyclists’ perceived risk in specific situations, factors influencing the perception of risk and cyclists’ knowledge about traffic rules regulating the interaction between road users in roundabouts.

One thousand and nineteen cyclists aged 18–85 participated in the study. Data were collected using structured interviews conducted in five Danish roundabouts.

Underestimation of risk and lack of knowledge about relevant traffic rules may contribute to car–bicycle collisions in roundabouts. Cyclists prefer road designs with a clear regulation of road user behaviour. A need to increase knowledge about traffic rules regulating road user behaviour in roundabouts is identified.     

Driver behavior during bicycle passing maneuvers in response to a Share the Road sign treatment

The interaction of motorists and bicyclists, particularly during passing maneuvers, is an area of concern to the bicycle safety community as there is a general perception that motor vehicle drivers may not share the road effectively with bicyclists. This is a particular concern on road sections with centerline rumble strips where motorists are prone to crowd bicyclists during passing events. One potential countermeasure to address this concern is the use of a bicycle warning sign with a “Share the Road” plaque. This paper presents the results of a controlled field evaluation of this sign treatment, which involved an examination of driver behavior while overtaking bicyclists. A series of field studies were conducted concurrently on two segments of a high-speed, rural two-lane highway. These segments were similar in terms of roadway geometry, traffic volumes, and other relevant factors, except that one of the segments included centerline rumble strips while the other did not. A before-and-after study design was utilized to examine changes in motor vehicle lateral placement and speed at the time of the passing event as they relate to the presence of centerline rumble strips and the sign treatment. Centerline rumble strips generally shifted vehicles closer to the bicyclists during passing maneuvers, though the magnitude of this effect was marginal. The sign treatment was found to shift motor vehicles away from the rightmost lane positions, though the signs did not significantly affect the mean buffer distance between the bicyclists and passing motorists or the propensity of crowding events during passing. The sign treatment also resulted in a 2.5 miles/h (4.0 km/h) reduction in vehicle speeds. Vehicle type, bicyclist position, and the presence of opposing traffic were also found to affect lateral placement and speed selection during passing maneuvers.     

A population based estimation of the driver protection provided by passenger cars: France 1996–2005

The technology used in cars to protect occupants is constantly developing. Demonstrating the beneficial effects in the field is complex as the most recent vehicles are generally used by drivers who differ from other drivers and who drive in different traffic conditions. This paper presents an overall estimation of the consequences of changes in the secondary safety of cars, taking account of most of these factors.The data come from information collected about injury road traffic crashes by the police in France between 1996 and 2005. The risk of the driver being killed has been evaluated for the 144,034 drivers involved in two-car crashes and for the 63,621 drivers involved in single-car crashes.The study shows that when a recent car is in collision with an older car the driver of the former is better protected than the driver of the latter. These improvements in secondary safety are not observed in the case of single-car crashes, very probably because of higher impact speeds. Our findings also confirm the need for protection systems to be better adapted to the specific characteristics of users and for an improvement in the crash compatibility of vehicles, in particular to overcome the consequences of differences between the masses of vehicles.     

Work-related road traffic collisions in the UK

Road traffic collisions while at work are the single largest cause of occupational fatality in the United Kingdom. Work-related road collisions do not comprise a homogenous group, but take many forms, encompassing the use of varying types of vehicle used for diverse purposes. A sample of over 2000 collision cases was considered, over 1000 in detail, from UK police forces, involving drivers/workers of all ages, and covering the years 1996-2004 inclusive. There were three key findings. (1) There were six main classes of collision-involved vehicles. These were company cars, vans/pickups, large goods vehicles (LGVs), buses (PCVs or ‘passenger carrying vehicles’), taxis/minicabs, and emergency vehicles (police, fire/rescue and ambulance). (2) The drivers of company cars, vans/pickups, and large goods vehicles (LGVs) all appeared to have a high ‘blameworthiness ratio’ in their collision involvement. Company car drivers showed excess speed as a causal factor, whereas van drivers showed more observational failures, and LGV drivers showed more fatigue and vehicle defects as factors. (3) The drivers of buses (PCVs), taxis/minicabs, and emergency vehicles showed a low ‘blameworthiness ratio’ in their collision involvement. Their problems seemed to be primarily with the other drivers/parties with whom they share the road. While they made a variety of mistakes or errors, they were more likely to become the victim of another party's mistake or error.     

That's close enough—A threshold effect of time headway on the experience of risk, task difficulty, effort, and comfort

Subjective impressions of task difficulty, risk, effort, and comfort are key variables of several theories of driver behaviour. A point of difference between many of these theories is not only the importance of these variables, but also whether they are continuously present and monitored or only experienced by individuals at certain critical points in the driving task. Both a threshold relationship and evidence of constant monitoring of risk and task difficulty have been found for speed choice. In light of these conflicting findings this study seeks to examine a different part of the driving task, the choice of time headway.Participants (N = 40, aged 19 to 30) drove in a simulator behind a vehicle travelling at 50 km/h at set time headways ranging from 0.5 seconds to 4.0 seconds. After each drive ratings of task difficulty, risk, comfort, and effort were collected. In addition participants were asked to drive at the time headway they preferred. In order to assess familiarity participants also drove on both the left and right hand side of the road and the role of driving experience was also examined.The results show support for a threshold awareness of task difficulty, risk, effort, and comfort in relation to time headway. Participant's ratings of these variables tended to be low or nil at large time headways, but then around the 2.0 second mark began to noticeably increase. Feelings of task difficulty, risk, and effort were also found to be highly correlated with each other. No effect of driving experience or side of the road was found.     

Driver experience and cognitive workload in different traffic environments

How do levels of cognitive workload differ between experienced and inexperienced drivers? In this study we explored cognitive workload and driver experience, using a secondary task method, the peripheral detection task (PDT) in a field study. The main results showed a large and statistically significant difference in cognitive workload levels between experienced and inexperienced drivers. Inexperienced, low mileage drivers had on average approximately 250 milliseconds (ms) longer reaction times to a peripheral stimulus, than the experienced drivers. It would, therefore, appear that drivers with better training and experience were able to automate the driving task more effectively than their less experienced counterparts in accordance with theoretical psychological models. It has been suggested that increased training and experience may provide attention resource savings that can benefit the driver in handling new or unexpected traffic situations.     

A comparison of static and dynamic hazard perception tests

Hazard perception is a vital component to safe driving and hazard perception tests (HPTs) are being used with greater frequency for driver training, assessment and licensure. In this study, we compared a dynamic HPT (Scialfa et al., 2011), which presents short video scenes to observers and a static HPT (Scialfa et al., 2012), which uses still images. Both tests require the observer to indicate the presence of a traffic conflict that would lead to a collision between the “camera” vehicle and another road user or fixed object. Young adult drivers (n = 56) completed both forms of the HPT, along with a modified version of the Driver Behavior Questionnaire ( Reason et al., 1990) and a measure of simple reaction time. Self-reported collision and moving violation data were also collected. As in previous work, both static and dynamic HPTs had good reliability. The correlation between composite static and dynamic scores was approximately .40, but was reduced to approximately .25 when simple reaction time was controlled. Both HPTs predicted lapses and errors on the Driver Behavior Questionnaire, but neither predicted self-reported collisions or moving violations. Discussion focuses on the differences in visual cues available in dynamic and static scenes and how these differences could influence decisions about potential hazards.     

Killer crashes: Fatal road traffic accidents in the UK

Road traffic accidents are responsible for over 3000 deaths per year in the UK, according to Department for Transport (2004a) figures. Although progress is being made in a number of areas, vehicle occupant fatalities have not been falling in line with casualty reduction targets for the year 2010. A sample of 1185 fatal vehicle occupant cases was considered, from ten UK police forces, from the years 1994-2005 inclusive. The main findings were: (1) over 65% of the accidents examined involved driving at excessive speed, a driver in excess of the legal alcohol limit, or the failure to wear a seat belt by a fatality, or some combination of these. (2) Young drivers have the great majority of their accidents by losing control on bends or curves, typically at night in rural areas and/or while driving for ‘leisure’ purposes. These accidents show high levels of speeding, alcohol involvement and recklessness. (3) Older drivers had fewer accidents, but those fatalities they were involved in tended to involve misjudgement and perceptual errors in ‘right of way’ collisions, typically in the daytime on rural rather than urban roads. Blameworthy right of way errors were notably high for drivers aged over 65 years, as a proportion of total fatal accidents in that age group.     

Culture related to road traffic safety: A comparison of eight countries using two conceptualizations of culture

The majority of previous cross-country studies of human factors relevant to traffic safety have not operationalized and measured culture. Also studies in this vein have mostly been carried out in Europe and the United States. The aim of the study was to examine country cluster differences, based on the Culture's Consequences framework, in road traffic risk perception, attitudes towards traffic safety and driver behaviour in samples from Norway, Russia, India, Ghana, Tanzania, Uganda, Turkey and Iran. An additional aim was to examine cluster differences in road traffic culture as symbol use and to investigate whether this theoretical cultural framework predicts risk perception, attitudes towards traffic safety and driver behaviour in the country clusters. The sample consisted of a total of 2418 individuals who were obtained by convenience sampling in the different countries. The countries segmented into four Culture's Consequences clusters; Norway, Russia and India, Sub-Saharan Africa, and Near East countries. The findings showed that Norwegians reported overall safer attitudes towards traffic safety and driver behaviour than the remaining country clusters. Individuals in Africa reported the highest risk perception. The countries also differed substantially in road traffic culture as symbol use. Contrary to established cultural theory, prediction models revealed that cultural factors were stronger predictors of driver behaviour than of risk perception. Also, the social cognitive risk constructs (i.e. risk perception and attitudes) solely explained variance in driver behaviour in the Norwegian and Russia/India clusters. Previous empirical efforts, which aimed to demonstrate that culture is important for the risk perception criterion, may have focused on a criterion variable that is not strongly related to driver behaviour. Furthermore, countermeasures aimed to influence social cognition may have stronger applicability in countries with a more individualistic western cultural orientation.     

Alcohol consumption,helmet use and head trauma in cycling collisions in Germany

Cycling, being easy, inexpensive and healthy, is becoming one of the most popular means of transport. Cyclists, however, are among the most vulnerable road users in traffic collisions.     

安全驾驶员与事故驾驶员视觉选择性注意的比较研究

本研究采用注意力测验量表，对132名公共汽车驾驶员的视觉选择性注意进行了测量。结果发现：(1)驾驶员的视觉选择性注意与交通事故关系密切．事故组驾驶员与安全组驾驶员的漏划数，完成时间和平均每秒正确删数存在显著差异．事故组驾驶员的漏划数较多．完成时间较长，平均每秒正确删数较少；(2)驾驶员视觉选择性注意的速度和准确性存在性别差异，女性驾驶员完成视觉选择性注意作业的时间较快、平均每秒正确删数较多。本研究结果为我国深入开展驾驶员的选拔、培训与安全教育提供一定的理论依据与技术手段。     

Texting while driving: Is speech-based text entry less risky than handheld text entry?

Research indicates that using a cell phone to talk or text while maneuvering a vehicle impairs driving performance. However, few published studies directly compare the distracting effects of texting using a hands-free (i.e., speech-based interface) versus handheld cell phone, which is an important issue for legislation, automotive interface design and driving safety training. This study compared the effect of speech-based versus handheld text entries on simulated driving performance by asking participants to perform a car following task while controlling the duration of a secondary text-entry task. Results showed that both speech-based and handheld text entries impaired driving performance relative to the drive-only condition by causing more variation in speed and lane position. Handheld text entry also increased the brake response time and increased variation in headway distance. Text entry using a speech-based cell phone was less detrimental to driving performance than handheld text entry. Nevertheless, the speech-based text entry task still significantly impaired driving compared to the drive-only condition. These results suggest that speech-based text entry disrupts driving, but reduces the level of performance interference compared to text entry with a handheld device. In addition, the difference in the distraction effect caused by speech-based and handheld text entry is not simply due to the difference in task duration.     

Objective and subjective evaluation of motor priming and warning systems applied to lateral control assistance

Previous research has shown that a device called “motor priming” (MP) was more effective than other lane departure warning systems. MP prompts drivers to take action by means of small asymmetric oscillations of the steering wheel. The first objective of this experiment was to provide a deeper understanding of MP mechanisms through a series of comparisons with other haptic and auditory systems. The results suggest that much of the improvement in recovery manoeuvres observed with MP is due to the motor cue (proprioceptive pre-activation of the gesture). Other factors, such as delivering the signal directly to the hands (stimulation of response effectors) or using the tactile modality rather than auditory warning, play a lesser role. This supports the hypothesis that MP devices directly intervene at the motor level, in contrast to more traditional warning systems, which only improve situation diagnosis. The second objective was to assess drivers’ acceptance of the assistance devices. A dissociation between efficiency and acceptance of the devices was observed: drivers globally preferred auditory warning to MP. The combination of auditory warning and motor priming appeared to be a good compromise to achieve both effectiveness and acceptance. This experiment illustrates the relevance of simulator studies when dangerous situations are the main targets of the investigation.     

Effects of major-road vehicle speed and driver age and gender on left-turn gap acceptance

Because the driver's gap-acceptance maneuver is a complex and risky driving behavior, it is a highly concerned topic for traffic safety and operation. Previous studies have mainly focused on the driver's gap acceptance decision itself but did not pay attention to the maneuver process and driving behaviors. Using a driving simulator experiment for left-turn gap acceptance at a stop-controlled intersection, this study evaluated the effects of major traffic speed and driver age and gender on gap acceptance behaviors. The experiment results illustrate relationships among drivers' left-turn gap decision, driver's acceleration rate, steering action, and the influence of the gap-acceptance maneuver on the vehicles in the major traffic stream. The experiment results identified an association between high crash risk and high traffic speed at stop-controlled intersections. The older drivers, especially older female drivers, displayed a conservative driving attitude as a compensation for reduced driving ability, but also showed to be the most vulnerable group for the relatively complex driving maneuvers.     

Multiple-vehicle traffic accidents in Hong Kong

‘Multiple-vehicle traffic accident’ refers to a crash between two or more moving objects. Unlike single-vehicle accidents, not all drivers involving in a multiple-vehicle accident are responsible for the occurrence of the event. Accordingly, variables such as road type, speed limit and number of vehicles involved in the accident are expected to play a much more important role in association with injury severity in multiple-vehicle accidents. To study the factors influencing injury severity of multiple-vehicle traffic accidents, a population-based study was conducted. The traffic accident data was obtained from the Traffic Accident Data System (TRADS), which was developed by the Transport Department, Police Force and Information Technology Services Department, Hong Kong. Multiple-vehicle traffic accidents (N = 10,630) occurring during the 2-year period 1999/2000 were considered. Potential risk factors such as district, human, vehicle, safety, environmental and site factors were examined. Categorizing injury severity into “fatal/serious” and “slight”, a stepwise logistic regression model was applied to the population data set. The district board, time of the accident, driver's gender, vehicle type, road type, speed limit and the number of vehicles involved are significant factors influencing the injury severity. Identification of risk factors for severe traffic accidents provides valuable information to help with new and improved road safety control measures.     

Nonresponse analysis and adjustment in a mail survey on car accidents

Statistical accident data plays an important role for traffic safety development involving the road system, vehicle design, and driver education. Vehicle manufacturers use data from accident mail surveys as an integral part of the product development process. Low response rates has, however, lead to concerns on whether estimates from a mail survey can be trusted as a source for making strategic decisions.