Fabrice Vienne

Crossing a two-way street: comparison of young and old pedestrians

INTRODUCTION Choosing a safe gap in which to cross a two-way street is a complex task and only few experiments have investigated age-specific difficulties. METHOD A total of 18 young (age 19-35), 28 younger-old (age 62-71) and 38 older-old (age 72-85 years) adults participated in a simulated street-crossing experiment in which vehicle approach speed and available time gaps were varied. The safe and controlled simulated environment allowed participants to perform a real walk across an experimental two-way street. The differences between the results for the two lanes are of particular interest to the study of visual exploration and crossing behaviors. RESULTS The results showed that old participants crossed more slowly, adopted smaller safety margins, and made more decisions that led to collisions than did young participants. These difficulties were found particularly when vehicles approached in the far lane, or rapidly. Whereas young participants considered the time gaps available in both lanes to decide whether to cross the street, old participants made their decisions mainly on the basis of the gap available in the near lane while neglecting the far lane. CONCLUSIONS The present results point to attentional deficits as well as physical limitations in older pedestrians. Several practical and have implications in terms of road design and pedestrian training are proposed.

Training the elderly in pedestrian safety: Transfer effect between two virtual reality simulation devices

OBJECTIVES A virtual-reality training program has been developed to help older pedestrians make safer street-crossing decisions in two-way traffic situations. The aim was to develop a small-scale affordable and transportable simulation device that allowed transferring effects to a full-scale device involving actual walking. METHODS 20 younger adults and 40 older participants first participated in a pre-test phase to assess their street crossings using both full-scale and small-scale simulation devices. Then, a trained older group (20 participants) completed two 1.5-h training sessions with the small-scale device, whereas an older control group received no training (19 participants). Thereafter, the 39 older trained and untrained participants took part in a 1.5-h post-test phase again with both devices. RESULTS Pre-test phase results suggested significant differences between both devices in the group of older participants only. Unlike younger participants, older participants accepted more often to cross and had more collisions on the small-scale simulation device than on the full-scale one. Post-test phase results showed that training older participants on the small-scale device allowed a significant global decrease in the percentage of accepted crossings and collisions on both simulation devices. But specific improvements regarding the way participants took into account the speed of approaching cars and vehicles in the far lane were notable only on the full-scale simulation device. DISCUSSION The findings suggest that the small-scale simulation device triggers a greater number of unsafe decisions compared to a full-scale one that allows actual crossings. But findings reveal that such a small-scale simulation device could be a good means to improve the safety of street-crossing decisions and behaviors among older pedestrians, suggesting a transfer of learning effect between the two simulation devices, from training people with a miniature device to measuring their specific progress with a full-scale one.

A vibrotactile wristband to help older pedestrians make safer street-crossing decisions

INTRODUCTION Older pedestrians are overrepresented in fatal accidents. Studies consistently show gap-acceptance difficulties, especially in complex traffic situations such as two-way streets and when vehicles approached rapidly. In this context, the present research was aimed at assessing the effectiveness of a vibrotactile device and study older pedestrians behavior when wearing the wristband designed to help them make safer street-crossing decisions. METHOD Twenty younger-old participants (age 60-69), 20 older-old participants (age 70-80) and 17 younger adults (age 20-45) carried out a street-crossing task in a simulated two-way traffic environment with and without a vibrotactile wristband delivering warning messages. RESULTS The percentage of decisions that led to collisions with approaching cars decreased significantly when participants wore the wristband. Benefits tended to be greater particularly among very old women, with fewer collisions in the far lane and when vehicles approached rapidly when they wore the wristband. But collisions did not fall to zero, and responses that were in accordance with the wristband advice went up to only 51.6% on average, for all participants. The wristband was nevertheless considered useful and easy to use by all participants. Moreover, behavioral intentions to buy and use such a device in the future were greater in both groups of older participants, but not among the younger adults. PRACTICAL APPLICATIONS This haptic device was able to partly compensate for some age-related gap-acceptance difficulties and reduce street-crossing risks for all users. These findings could be fruitfully applied to the design of devices allowing communication between vehicles, infrastructures, and pedestrians.

Improving motorcycle conspicuity through innovative headlight configurations

Most motorcycle crashes involve another vehicle that violated the motorcycles right-of-way at an intersection. Two kinds of perceptual failures of other road users are often the cause of such accidents: motorcycle-detection failures and motion-perception errors. The aim of this study is to investigate the effect of different headlight configurations on motorcycle detectability when the motorcycle is in visual competition with cars. Three innovative headlight configurations were tested: (1) standard yellow (central yellow headlight), (2) vertical white (one white light on the motorcyclists helmet and two white lights on the fork in addition to the central white headlight), and (3) vertical yellow (same configuration as (2) with yellow lights instead of white). These three headlight configurations were evaluated in comparison to the standard configuration (central white headlight) in three environments containing visual distractors formed by car lights: (1) daytime running lights (DRLs), (2) low beams, or (3) DRLs and low beams. Video clips of computer-generated traffic situations were displayed briefly (250ms) to 57 drivers. The results revealed a beneficial effect of standard yellow configuration and the vertical yellow configuration on motorcycle detectability. However, this effect was modulated by the car-DRL environment. Findings and practical recommendations are discussed with regard to possible applications for motorcycles.