Impacts of Intersection Treatments and Traffic Characteristics on Bicyclist Safety

The primary research objectives for this project are as follows: (1) Determine which factors affect the frequency and/or severity of bicycle vehicle-conflicts at intersections with different bicycle-related treatments such as mixing zones, leading bike interval (LBI), split LBI, as well as those traditional bicycle lanes and with no treatments, and others as feasible identified through consultation with TAC. (2) Provide data-driven guidance as to the efficacy of certain intersection treatments in mitigating vehicle-bicycle conflicts (thereby improving bicyclist safety by this surrogate measure), including consideration of how traffic and site characteristics impact these conflicts. (3) Develop a countermeasure selection ‘toolbox’ which describes the performance (in terms of bicycle-vehicle conflicts) of bicycle-specific intersection treatments under different geometric and traffic conditions. A desired outcome of this research will be determination of threshold bicycle and vehicle volumes where specific levels of treatments (e.g. pavement markings, geometry, signal treatments, or combinations of these) should be considered over others. Recommendations will be provided on the advantages/disadvantages of different treatments, and descriptions of conditions under which each treatment should/could be considered (both traffic and geometric conditions), as well as approximate time frames for implementation for each treatment.