Highlighting Bicyclist Biological Motion Enhances Their Conspicuity in Daylight

• Published in: Accident analysis and prevention 2020-07, Vol.142, p.105575-105575, Article 105575
• Main Authors: Edewaard, Darlene E., Fekety, Drea K., Szubski, Ellen C., Tyrrell, Richard A.
• Format: Article
• Language: English
• Subjects: Bicyclist safety; Biological motion; Conspicuity; Transportation safety; Visual perception
• ISSN: 0001-4575; 1879-2057
• DOI: 10.1016/j.aap.2020.105575

•In daylight, ratings of bicyclist rear conspicuity were higher when rear-facing lights were mounted to the bicyclist’s ankles than when a taillight was mounted to the seat post (either on or off) or to the helmet.•When a taillight was mounted to the seat post, daytime conspicuity ratings were higher when the taillight was flashing than when it was always on.•In daylight, the distance from which participants recognized the presence of a bicyclist was over 3 x greater when the bicyclist’s fluorescent yellow jersey was paired with matching leg covers than when the leg covers were absent.•Thus, bicyclists can significantly enhance their rear conspicuity in daytime by using active lighting or fluorescent garments to highlight their pedaling movements. For safety purposes, it is critical that bicyclists be conspicuous to drivers. We report two experiments that investigated the benefits of bicycle taillights and fluorescent clothing for enhancing the bicyclist’s rear conspicuity in daylight. In Experiment 1, 24 participants sat in a car parked on a closed road at each of three distances and rated the conspicuity of four bicyclists displaying taillights that varied in their placement, intensity, and mode. The results confirmed that bicycle taillights can significantly enhance conspicuity in daylight. Varying the placement of the taillights revealed that having an “always on” taillight mounted to each of the rider’s ankles was the most conspicuous location to mount taillights, and this effect was particularly strong at greater viewing distances. For seat post-mounted taillights, flashing taillights were rated as more conspicuous. In Experiment 2, 186 participants were passengers on a short drive during which they pressed a button each time they recognized that a bicyclist was present. Each participant passed a test bicyclist wearing one of four clothing configurations. When the cyclist wore a fluorescent yellow jersey paired with fluorescent yellow leg covers, participants responded from a distance that was 3.3 times greater than when the cyclist wore the same jersey without the yellow leg covers. Both of these experiments demonstrate that highlighting bicyclists’ pedaling motion enhances their conspicuity when viewed from behind. These results further emphasize the conspicuity benefits of biological motion and provide bicyclists with techniques to enhance their own conspicuity in daylight.