There have been many studies in recent decades investigating how “visibility aids” affect the ease with which drivers are able to spot cyclists on the road.
According to a new study, a fluorescent yellow jersey did not significantly improve the cyclist’s conspicuity relative to a black jersey.
However when the cyclist paired the fluorescent jersey with fluorescent yellow leggings, participants responded from a distance 3.3x farther than an identical outfit with black leggings.
The study involved 186 people being driven along a road by a researcher and asked to press a button on a keypad each time they identified a person “on or with” a bicycle, whether “stopped or moving” and who was “in or near the roadway.”
“The finding that fluorescent yellow leggings can provide a dramatic enhancement to bicyclist conspicuity is, we believe, a consequence of highlighting the bicyclist’s pedaling motion”, the researchers said.
“The rhythmic up-down movements of a cyclist’s lower legs uniquely specify a pedaling motion that is visually distinct from, for example, a pedestrian walking or jogging. Further, considerable research has identified that highlighting a cyclist’s biological motion can provide powerful conspicuity enhancements. Thus fluorescent leggings can offer a powerful and low-tech tool for enhancing bicyclists’ daytime conspicuity”.