title: Bicyclists overestimate their own night-time conspicuity and underestimate the benefits of retroreflective markers on the moveable joints.
abstract: 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. Participants wore black clothing alone or together with a fluorescent bicycling vest, a fluorescent bicycling vest with additional retroreflective tape, or the fluorescent retroreflective vest plus ankle and knee reflectors in a modified 'biomotion' configuration. The bicycle had a light mounted on the handlebars which was either static, flashing or off. Participants judged that black clothing made them least visible, retroreflective strips on the legs in addition to a retroreflective vest made them most visible and that adding retroreflective materials to a fluorescent vest provides no conspicuity benefits. Flashing bicycle lights were associated with higher conspicuity than static lights. Additionally, occasional bicyclists judged themselves to be more visible than did frequent bicyclists. Overall, bicyclists overestimated their conspicuity compared to previously collected recognition distances and underestimated the conspicuity benefits of retroreflective markings on their ankles and knees. Participants mistakenly judged that a fluorescent vest that did not include retroreflective material would enhance their night-time conspicuity. These findings suggest that bicyclists have dangerous misconceptions concerning the magnitude of the night-time conspicuity problem and the potential value of conspicuity treatments.
authors.affiliation: School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia. j.wood@qut.edu.au
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Wood
authors.forename: Richard A
authors.initials: RA
authors.lastname: Tyrrell
authors.forename: Ralph
authors.initials: R
authors.lastname: Marszalek
authors.forename: Philippe
authors.initials: P
authors.lastname: Lacherez
authors.forename: Trent
authors.initials: T
authors.lastname: Carberry
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control*; D000293:Adolescent; D000328:Adult; D001642:Bicycling / Q000293:injuries*; D016022:Case-Control Studies; D003020:Clothing; D015350:Contrast Sensitivity; D003624:Darkness; D005260:Female; D005556:Form Perception; D006801:Humans; D007600:Judgment; D008029:Lighting; D008297:Male; D008875:Middle Aged; D011930:Reaction Time; D014792:Visual Acuity; D055815:Young Adult