Dean Taylor

Review of basic research in bicycle traffic science, traffic operations, and facility design

Recent emphasis on alternatives to automobile transportation has brought to light deficiencies in basic research performed in bicycle traffic science. Because of limited opportunities to fund such research, it is prudent to use past research to develop design guidelines and provide a basis for planning future research efforts. Mainly toward the latter end, a comprehensive review of published basic research in bicycle traffic science (with relevance to U.S. traffic) is presented, and suggestions are made for research priorities.

Coordinating traffic signals for bicycle progression

Traffic signal coordination that provides either (a) progression for bicycles or (b) simultaneous progression for bicycles and automobiles traveling on the same facility is analyzed. A conceptual foundation, consisting of three primary contributions, is developed for analyzing bicycleautomobile mixed-traffic progression along signalized streets. First, the principal considerations for bicycle progression are articulated. Second, several concepts and techniques that provide improved (or alternative) multiobjective solutions are presented and analyzed. Third, a multiobjective formulation framework for solving the mixed-traffic design problem is proposed. This framework formally incorporates the elements that were introduced as part of the first two contributions and provides a method to handle the inherent competing objectives of the situation. Additionally, important practical aspects of designing and implementing bicycle progression systems, such as handling bicycle speed variability and selecting appropriate facilities for initial (or test) projects, are identified and discussed.

Sidewalk Cross-Slope Requirements of the Americans with Disabilities Act: Literature Review

It is the long-term intent of the Americans with Disabilities Act (ADA) that publicly available services along a public street be accessible to people with disabilities via a continuous, unobstructed pedestrian circulation network. When altered, almost all streets, with the exception of rural roads and highways, will be required to provide an accessible side-walk wherever feasible. Existing research and science related to side-walk cross-slope requirements are described in detail. The history and spirit of the ADA are summarized, relevant court decisions are discussed, and key ADA cross-slope–related requirements are identified (along with applicable caveats). Current practices rely on a combination of strict, but limited, physical solutions and some programmatic solutions, about which there is much uncertainty as to how and when they should be applied. Very little existing work considers the effort and other access differences that result from changes in cross slope. Thus, additional research is needed to ensure sound policy regarding user access to transportation facilities.