Effects of Different Levels of Refractive Blur on Nighttime Pedestrian Visibility.

Purpose: The aim of this study was to systematically investigate the effect of different levels of refractive blur and driver age on nighttime pedestrian recognition and determine whether clothing that has been shown to improve pedestrian conspicuity is robust to the effects of blur.

Methods: Nighttime pedestrian recognition was measured for 24 visually normal participants (12 younger mean = 24.9 ± 4.

Configuring retroreflective markings to enhance the night-time conspicuity of road workers.

This study investigated whether the night-time conspicuity of road workers can be enhanced by positioning retroreflective strips on the moveable joints in patterns that convey varying degrees of biological motion. Participants were 24 visually normal adults (12 young M=26.8 years; 12 older M=72.

Differential effects of refractive blur on day and nighttime driving performance.

Purpose: To investigate the effect of different levels of refractive blur on real-world driving performance measured under day and nighttime conditions.

Methods: Participants included 12 visually normal, young adults (mean age = 25.8 ± 5.

Bicyclists overestimate their own night-time conspicuity and underestimate the benefits of retroreflective markers on the moveable joints.

Conspicuity limitations make bicycling at night dangerous. This experiment quantified bicyclists' estimates of the distance at which approaching drivers would first recognize them. Twenty five participants (including 13 bicyclists who rode at least once per week, and 12 who rode once per month or less) cycled in place on a closed-road circuit at night-time and indicated when they were confident that an approaching driver would first recognize that a bicyclist was present.

Even moderate visual impairments degrade drivers' ability to see pedestrians at night.

Purpose: To determine the effect of moderate levels of refractive blur and simulated cataracts on nighttime pedestrian conspicuity in the presence and absence of headlamp glare.

Methods: The ability to recognize pedestrians at night was measured in 28 young adults (M = 27.6 years) under three visual conditions: normal vision, refractive blur, and simulated cataracts; mean acuity was 20/40 or better in all conditions.

Using reflective clothing to enhance the conspicuity of bicyclists at night.

Bicycling at night is more dangerous than in the daytime and poor conspicuity is likely to be a contributing factor. The use of reflective markings on a pedestrian's major joints to facilitate the perception of biological motion has been shown to greatly enhance pedestrian conspicuity at night, but few corresponding data exist for bicyclists. Twelve younger and twelve older participants drove around a closed-road circuit at night and indicated when they first recognized a bicyclist who wore black clothing either alone, or together with a reflective bicycling vest, or a vest plus ankle and knee reflectors.

Using biological motion to enhance the conspicuity of roadway workers.

This study examined whether the conspicuity of road workers at night can be enhanced by distributing retroreflective strips across the body to present a pattern of biological motion (biomotion). Twenty visually normal drivers (mean age = 40.3 years) participated in an experiment conducted at two open-road work sites (one suburban and one freeway) at night-time.

Hearing impairment affects older people's ability to drive in the presence of distracters.

Objectives: To investigate the effects of hearing impairment and distractibility on older people's driving ability, assessed under real-world conditions.

Design: Experimental cross-sectional study.

Setting: University laboratory setting and an on-road driving test.

Drivers' and cyclists' experiences of sharing the road: incidents, attitudes and perceptions of visibility.

This study explored the beliefs and attitudes of cyclists and drivers regarding cyclist visibility, use of visibility aids and crashes involving cyclists and motorists. Data are presented for 1460 participants (622 drivers and 838 cyclists) and demonstrate that there are high rates of cyclist-vehicle crashes, many of which were reported to be due to the driver not seeing the cyclist in time to avoid a collision. A divergence in attitudes was also apparent in terms of attribution of responsibility in cyclist-vehicle conflicts on the road.

Seeing pedestrians at night: visual clutter does not mask biological motion.

Although placing reflective markers on pedestrians' major joints can make pedestrians more conspicuous to drivers at night, it has been suggested that this "biological motion" effect may be reduced when visual clutter is present. We tested whether extraneous points of light affected the ability of 12 younger and 12 older drivers to see pedestrians as they drove on a closed road at night. Pedestrians wore black clothing alone or with retroreflective markings in four different configurations.