Nicholas J. Ward

Identification of differences between rural and urban safety cultures

The prevailing risk of traffic fatalities is much larger in rural areas compared to urban areas. A number of explanations have been offered to explain this including road design, emergency medical service proximity, and human factors. This research explored the potential contribution of rural driver attitudes that may underlie the increased fatal crash risk in rural environments. This analysis examined differences between rural and urban drivers in terms of self-reported risk taking for driving behaviors associated with fatal crashes and attitudes toward safety interventions using a large-scale survey. The results suggested that rural drivers engage in riskier behavior, such as not wearing seatbelts, because they have lower perceptions of the risks associated with such behaviors. Results also suggested that vehicle type (e.g., pickup trucks versus passenger vehicles) may be related to seatbelt compliance and frequency of driving under the influence of alcohol. Rural drivers perceived the utility of government-sponsored traffic safety interventions to be lower than their urban counterparts. This study provides insights into the role of the human factor in rural fatal crashes and provides policy suggestions for developing safety interventions that are designed with respect to the psychosocial factors that define the rural culture.

Automation of task processes: An example of intelligent transportation systems

The sophistication of advanced automated technologies offer unprecedented opportunities to improve system and operator safety, efficiency, and comfort. However, these applications fundamentally alter the task process by virtue of the degree of automatic control these systems may exert over levels of the task (i.e., control, tactical, strategic). This article presents a discussion of the possible deleterious effects of automated technology in the transport context in relation to Intelligent Transport Systems (ITS). The potential deleterious effects of ITS include (a) shifting the driver out-of-the-loop, such that situation awareness and responsiveness to critical events may be impaired, and (b) behavioral adaptation that undermines system effectiveness. Examples of both effects are presented in relation to an evaluation of an experimental Adaptive Cruise Control system. The importance of considering these effects as part of a formal evaluation protocol is identified in order to maximize the design benefits of ITS. A framework and methodology for the evaluation of automated systems is proposed.

Effects of alcohol impairment on motorcycle riding skills

Alcohol intoxication is a significant risk factor for fatal traffic crashes; however, there is sparse research on the impairing effects of alcohol on skills involved in motorcycle control. Twenty-four male motorcycle riders between the ages of 21 and 50 were assessed on a test track with task scenarios based on the Motorcycle Safety Foundations (MSF) training program. A balanced incomplete block design was used to remove confounding artifacts (learning effects) by randomizing four BAC levels across three test days. In general, intoxicated riders demonstrated longer response times and adopted larger tolerances leading to more task performance errors. Most of the alcohol effects were evident at the per se 0.08% alcohol level, but some of the effects were observed at the lower 0.05% alcohol level. The effects of alcohol on motorcycle control and rider behavior were modest and occurred when task demand was high (offset weave), time pressure was high (hazard avoidance for near obstacles), and tolerances were constrained (circuit track). The modest effects may be due to the study design, in which experienced riders performed highly practiced, low-speed tasks; alcohol at these levels may produce larger effects with less experienced riders in more challenging situations.

Effect of Background Scene Complexity and Field Dependence on the Legibility of Head-Up Displays for Automotive Applications

This study examined the legibility of information presented on head-up displays (HUDs) for automotive application as a function of background scene complexity, the position of the HUD within field of view relative to the background scene, and the perceptual capacity of the perceiver. Groups of field-dependent and fieldindependent subjects viewed video footage from the perspective of following a lead caron an open road with low, moderate, and high scene complexity. Subjects were required to track the lead vehicle and identify HUD-presented targets of a specified orientation and specified changes in a HUD-presented speedometer. The results indicate that (a) HUD legibility deteriorated with increased visual complexity of the background scene; (b) positioning the HUD on the roadway reduced the effect of background scene complexity on HUD legibility; and (c) field-dependent subjects made fewer correct and more false positive target identifications than did field-independent subjects.

Enhanced presence in driving simulators using autonomous traffic with virtual personalities

The paper summarizes a project to increase the sense of presence within a driving simulator while interacting with autonomous traffic. The project sought to model natural variations in ambient traffic to emulate identifiable driving styles for different categories of driver. Probability distributions combined with decision histories were employed to characterize speed choice while providing a mechanism for introducing temporal and spatial variation in speed changes. These efforts produced virtual personalities representing different categories of ambient traffic including generic, male, female, old, drunk, aggressive, cautious, and fatigued. A user evaluation of the ambient traffic concluded that naturalistic variation in behavior can significantly contribute to the subjective realism of the interaction with traffic simulation.

An evaluation of a lane support system for bus rapid transit on narrow shoulders and the relation to bus driver mental workload.

The use of dedicated bus shoulders is a key method for implementing bus rapid transit (BRT) in areas that do not have the space for additional infrastructure. However, the narrow width of the bus shoulder and the need to anticipate traffic hazards in the adjacent lane can both be significant stressors for bus drivers. Bus driver mental workload and stress in response to these conditions should be a significant concern both for operational safety and driver health. This pilot study evaluated the potential stressors of traffic density and shoulder width in the context of an express BRT service in a large US metropolitan area. In addition, the study considered the potential role of a prototype lane support system (LSS) to support vehicle control within the narrow shoulder boundaries. Ten experienced bus drivers drove an actual route with an instrumented bus equipped with and without LSS. Self-reported effort was recorded along with performance measures of speed and position control relevant to mobility and safety objectives. Bus drivers did note stressors in the BRT environment and the prototype LSS. However, the use of the shoulder during high-density traffic conditions did improve mobility. Moreover, the LSS did enhance safety on the shoulder when there was high-density traffic in the adjacent lane. However, there was no evidence that the LSS reduced bus driver workload while operating in the narrow shoulder. Future research should consider the impact of BRT operations and support systems on bus driver mental workload and stress, and support the deployment of such devices for bus operations on shoulders during high traffic volumes.

Quantifying Car following Performance as a Metric for Primary and Secondary (Distraction) Task Load: Part A — Modification of Task Parameters

Driver impairment as a result of attention-related factors is a common concern to many areas of safety research in driving. Previously, the “coherence technique” was developed to provide several metrics of performance in relation to the continuous task of car following presumed to require vigilance and perceptual capacity (Brookhuis, De Waard, & Mulder, 1994). This study examines a modified version of this technique that is more natural. This modified technique was sensitive to both increased primary and secondary (distraction) task load.

SIMULATION OF ACCIDENT RISK DISPLAYS IN MOTORWAY DRIVING WITH TRAFFIC

The study used a vehicle-based driving simulator to evaluate two graphical displays, one showing risk probability in terms of safety margin (Time Headway, TH), and one showing risk severity in terms of Kinetic Energy (KE). Twenty-seven subjects were randomly allocated to one of three experimental conditions: Control, TH, and KE. Subjects undertook three driving tasks (ABA design). For the second driving task in the TH and KE conditions, subjects drove in the presence of their respective feedback displays. Measures of TH and KE levels were taken, as well as subjective measures of risk and task loading. It was found that the KE display was more effective than the TH display in reducing the proportion of time subjects spent at short headways. The KE display was also effective in reducing the proportion of time subjects spent at high speed. The KE display appeared to affect the perception of risk (severity of potential accidents). It was concluded that further research evaluating displays that combined the positive effects of both parameters within a single representation display is needed.

Occupational suitability bias for full-time and part-time employment in sex-typed jobs

The present study examines the effects of employment status (full time, part time), job sex type, and job applicant sex upon judgments of occupational suitability. Sixty-three male and 176 female undergraduate students (ranging in age between 17 and 32 years) read a brief vignette describing either a man or a woman. Subjects then rated the occupational suitability of the person for three male sex-typed jobs (plumber, bus driver, cabinetmaker) and three female sex-typed jobs (secretary, telephone operator, hairdresser). In one condition subjects were explicitly told that these jobs were full time. In a second condition subjects were explicitly told that these jobs were part time. Results indicated a sex-congruency bias for both full time and part time employment. However, there was evidence that sex congruency bias is reduced for part-time employment.

Research Note: Cannabis and Driving — Research Needs and Issues for Transportation Policy

This paper summarizes current knowledge regarding the effects of cannabis use on driving. Psychopharmacological evidence has shown that cannabis, unlike alcohol, can be detected several days after consumption. Prevalence data has revealed that cannabis use is increasing, and that as many as 90% of study participants were willing to drive after consuming a typical dose. A review of laboratory studies found that cannabis and alcohol affect different driving tasks. When cannabis and alcohol use were evaluated in simulated and on-road driving situations, drivers were more aware of being intoxicated after using cannabis and thus invoked greater compensatory effort to offset impairment in the driving task. The effect of cannabis use on crash risk has shown that recent use increases crash risk, but not as much as alcohol consumption. This paper concludes that further research is needed before specific transportation policy can be developed for cannabis.