Research has identified a relatively high incidence (8.4%) bicycle/motor-vehicle accident type in which a bicyclist initiates a left-hand turn without searching to the rear or signaling and is struck by an overtaking motor vehicle. In order to consider countermeasures to this accident type, it was necessary to understand the frequency with which bicyclists actually search behind before turning left, and to determine the ability of bicyclists to maintain lateral stability when looking behind. Hence, two separate studies were conducted. The first, a field-observation study, was performed to assess the frequency with which bicyclists search behind before initiating a left-hand turn. The second experiment measured the magnitude of the inadvertent lateral deviations that accompany a rearward search as a function of the bicyclist's age and riding experience.
Abstract