The researchers Eva Fabriek and Dick de Waard state that the visual characteristics of road design play an important role in preventing accidents by cyclists with visual handicaps. They base their results on questionnaires filled in by, and discussions held with, visually handicapped cyclists and seniors suffering from macular degeneration, a frequent ocular ailment of the elderly. In addition they held trials in which the field of view and contrast were artificially reduced while the participants cycled through a test track.
The questionnaires revealed that 45% of respondents had at one time or other fallen or ridden against an obstacle – usually the kerb or a bollard. During the trial, participants had to contend with regular bollards as well differently coloured bollards, bollards with lights, or lights set in the road. They also contended with kerbs painted white, unpainted kerbs, kerbs with special patterns as well as marked and unmarked soft shoulders. The investigation showed that bollards, kerbs and markings are important visual elements for this group. Riding performance diminished and insecurity increased when cyclists were unable to see obstacles and when the road ahead was difficult to make out. 41% of the participants preferred the standard red-white bollards. Illumination did not improve matters, contrary to expectations. 40% of the participants also preferred marked kerbs. 100% preferred higher contrast markings.
The researchers concluded that visibility of objects could be improved by colouring bollards – insofar as they cannot be avoided – red and white. One can in addition consider laying down white kerbs. Also high contrast markings can help the visually handicapped as well as a bright road surface that contrasts with the soft shoulder. Finally, bollards and other road posts should not be placed immediately after a curve, but only on straight road segments.