BICYCLE INTERACTION HAZARD SCORE: A THEORETICAL MODEL

A calibrated and transferrable model is needed to estimate bicyclists' perception of the hazards of sharing roadway segments with motor vehicles. Such an interaction hazard (perception) model would help overcome one of the barriers to the development of a sequential bicycle travel demand simulation or forecasting model. An interaction hazard model would also greatly aid planners in the priority ranking of competing roadway segments for on-road bicycle facilities by providing an objective and stable supply-side measure of bicycle facility need. In addition, a model would assist planners to objectively assess the overall bicycle friendliness of their road networks as well as provide a uniform tool to assist in the development of bicycle suitability maps. The theoretical interaction hazard score (IHS) model described in this paper represents an opportunity, after statistical calibration (and the possible incorporation of roadway grade and curvature terms for application in hilly terrain), to fulfill the aforementioned needs. On the basis of consensus group evaluation, the IHS model incorporates the appropriate exposure variables that describe actual and perceived interaction hazards to bicyclists sharing parallel facilities with motor vehicles.