Robert B. Isler

CHILD PEDESTRIANS' CROSSING GAP THRESHOLDS

Three gender-balanced groups of 16 school children (5-6 years, 8-9 years, 11-12 years) participated in individual pretests of vision, hearing, and time to walk across a 12-m wide urban street and back. Each child then completed 10 roadside trials requiring judgement of the threshold point at which they would no longer cross in front of traffic approaching from their right. The judgements were made from a site immediately in front of a parked car at a point 2 m from the kerb and 4 m from the centre of the road. Traffic speeds and distances were measured using a laser speed and distance detector. The results indicated that, overall, distance gap thresholds remained constant regardless of vehicle approach speeds. Analysis of the thresholds for distance gap judgements for the 4-m half-street crossing showed that some of the older children could be expected to make safe decisions, but this was not so for the 5-6- and 8-9-year-olds at vehicle approach speeds above 60 kph. Almost two-thirds of the children reported using distance to judge gaps, which proved the least adequate strategy in terms of proportion of resultant safe decisions. The findings are discussed in relation to developing effective child pedestrian safety strategies.

Video-based road commentary training improves hazard perception of young drivers in a dual task

This study used a video-based hazard perception dual task to compare the hazard perception skills of young drivers with middle aged, more experienced drivers and to determine if these skills can be improved with video-based road commentary training. The primary task required the participants to detect and verbally identify immediate hazard on video-based traffic scenarios while concurrently performing a secondary tracking task, simulating the steering of real driving. The results showed that the young drivers perceived fewer immediate hazards (mean=75.2%, n=24, 19 females) than the more experienced drivers (mean=87.5%, n=8, all females), and had longer hazard perception times, but performed better in the secondary tracking task. After the road commentary training, the mean percentage of hazards detected and identified by the young drivers improved to the level of the experienced drivers and was significantly higher than that of an age and driving experience matched control group. The results will be discussed in the context of psychological theories of hazard perception and in relation to road commentary as an evidence-based training intervention that seems to improve many aspects of unsafe driving behaviour in young drivers.

Effects of higher-order driving skill training on young, inexperienced drivers’ on-road driving performance

The aim of the current study was to compare the effects of training in higher-order driving skills (e.g., perceptual, motivational, insight) and vehicle handling skill training in relation to on-road driving performance, hazard perception, attitudes to risky driving and driver confidence levels in young, inexperienced drivers. Thirty-six young drivers (23 males and 13 females, average age 16.3 years), mostly on a restricted NZ driver licence, participated in a Driver Training Research camp. Participants were randomly allocated to one of three equally sized groups according to the type of driving skill training (5 days) they received: higher-order, vehicle handling or control (no training). Professional driver assessors conducted a comprehensive driving assessment before (Baseline) and after the training (Post Training). At both time points, participants also carried out a computerised hazard perception task, and completed self-report questionnaires to assess attitudes to risky driving and driver confidence. In terms of on road driving, the participants who received higher-order driving skill training showed a statistically significant improvement in relation to visual search and the composite driving measure. This was accompanied by an improvement in hazard perception, safer attitudes to close following and to dangerous overtaking and a decrease in driving related confidence. The participants who received vehicle handling skill training showed significant improvements in relation to their on-road direction control, speed choice and the composite driving score. However, this group showed no improvement in hazard perception, attitudes to risky driving or driver confidence. The findings will be discussed in the context of driver training as a viable crash prevention intervention in regard to young, inexperienced drivers.

Examining the link between information processing speed and executive functioning in multiple sclerosis.

Slowed information processing speed (IPS) is frequently reported in those with multiple sclerosis (MS), and at least 20% are compromised on some aspect of executive functioning also. However, any relationship between these two processes has not been examined. The Sternberg Memory Scanning Test, Processing Speed Index (WAIS-III), Delis Kaplan Executive Function System (D.KEFS), and Working Memory Index (WMS-III) were administered to 90 participants with MS. Their performance on the PSI was significantly below the normative scores but no deficits in memory scanning speed were evident. The initial response speed of the Sternberg and the PSI were more closely related to D.KEFS performance, particularly in timed tasks with a high cognitive demand (switching tasks). In contrast, memory scanning speed was related to working memory. This study reinforces the link between IPS and working memory in MS, and supports the suggestion that IPS is not a unitary construct.

Testing the relative conspicuity of safety garments for New Zealand forestry workers

The relative conspicuities of six test garments (fluorescent orange, green/red, high-contrast, fluorescent lime-yellow, white, black) were assessed to guide the selection process of a standard upper body safety garment to be used within the New Zealand logging industry. Six male and four female participants, aged between 18 and 26 years, volunteered to perform 10 trials each on a demanding, central (tracking) task, while peripherally searching colour slides for test garments displayed on each of eight positions, against a pine forest background typically found in the New Zealand forestry. During each trial, transparency luminance was first gradually increased from darkness to daylight and then decreased to darkness again within 180 s. A head mounted ASL eye tracking system (4000SU) recorded the eye line of gaze for each participant, enabling a rank order of detection to be obtained for the tested garments in each trial. The fluorescent lime-yellow, fluorescent orange and white test garments were detected earlier than any other test garments across all trials, and the fluorescent lime-yellow test garment was detected first with a higher frequency than the white test garment. It was concluded that while white may be the most visible colour in near darkness conditions, as it provides highest contrast, fluorescent lime-yellow stands out better in twilight and daylight conditions against the pine forest background. The results of this study led to the promotion of fluorescent lime-yellow as the standard safety colour used in upper body garments within the New Zealand forest industry.