Cities around the United States are increasingly seeking to modernize and enhance their bicycling infrastructure with the aim of accommodating a greater number of people who are willing to bicycle for transportation. Cities are employing separated (or protected) bike lanes in greater numbers (213 installations as of August 2015, according to the Green Lanes Project Protected Bike Lanes inventory). While the transportation industry is developing some consensus on midblock design approaches, there is less consensus on intersection design where most crashes occur. Efforts to address crash risk have focused on two main philosophies: 1) reduce separation prior to the intersection by channeling bicyclists toward motor vehicle traffic, and 2) maintain separation at intersections. The first philosophy is accomplished through creating mixing zones or truncated bike lanes, which increase mutual visibility and, in some cases, move turning motorists across through bicyclists prior to the intersection. The second philosophy is accomplished through separating movements in time (e.g., with a bike signal and protected phase) or, by maintaining protection to the intersection to channel bicyclists away from traffic to provide motorists additional space and time to see and react to cyclists (e.g., with protected intersections). Recent studies and guide books have contributed important data and design options (e.g. “Lessons from the Green Lane: Evaluating Protected Bike Lanes in the U.S.” and the “Separated Bike Lane Planning and Design Guide”); however a more thorough resource for protected bike lane intersection design selection and implementation is needed in order to ensure agencies are implementing the safest designs possible, and to bring consistency to designs around the country.
We propose to use our extensive experience evaluating protected bike lanes and other innovative bicycle facilities and strong relationships with the project partners (and in many cases, productive prior relationships evaluating bicycle facilities together) to create a timely and useful resource for selecting and implemented intersection designs for protected bike lanes. Our proposal for this research consists of two phases. In Phase 1, we will identify and document a breadth of intersection design types, informed by a review of existing designs, literature, and current best practices. Upon the completion of Phase 1 and approval of Phase 2, the research team will prepare a draft work plan that includes a detailed task description, schedule and budget. This approach will allow us to identify and isolate successful design elements and potential countermeasures, and to develop a final report that will serve as a valuable tool for cities around the county.