A retrospective study of bicycle collisions in Metropolitan Toronto during the school year 1969-70 was undertaken to identify the occurrence and contribution to risk of selected rider, bicycle, and environmental factors. The study samples consisted of 275 bicyclists in reportable traffic collisions and a random comparison group of 1,062 male bicycle owners. Several factors influencing the risk of young bicyclists were identified. These related primarily to the comprehension of risk inherent in different roadway environments, the prediction of traffic movement, and the control of the bicycle in traffic.

The collision-involved bicyclist was found to be largely unguided by the conventional abstract rules of roadway placement and priority, responding only to immediate and obvious traffic conflicts. Collisions occurred most frequently in rush hour traffic flows;​ a high proportion were related to environmental deficiencies such as severe obstructions to view, substantial grades, and darkness or rain conditions.

A large number of young riders experienced excess risk when riding bicycles which were out of proportion to the rider's height and leg reach to the ground. Among younger riders (8-10 years olds in this study) a five-fold increase in risk was found for those who could not reach their pedals comfortably when seated.