NCHRP REPORT 770: ESTIMATING WALKING AND BICYCLING FOR PLANNING AND PROJECT DEVELOPMENT
Transportation Research Board - Washington, DC
The National Cooperative Highway Research Program (NCHRP) put a call out for research to address a long-standing need for more robust analytic tools to support planning for non-motorized travel modes. These needs range from more realistic accounting of non-motorized travel in regional planning to the design of mixed-use communities and multimodal corridors and, ultimately, to the design of efficient and safe non-motorized travel networks and individual facilities. In response, Renaissance led a prominent research team in developing a practitioner guidebook on methods and tools for practitioners to estimate bicycling and walking demand as part of regional, corridor, or project-level analyses.
Research confirms that people make walk and bike travel choices based on evaluating the “utility” they represent relative to the purpose of the trip, the travel options available at the origin and destination of the trip, the socio-demographics of the traveler, and the intangibles of individual attitudes and preferences. The utility of a walk or bike trip is highly location or place-based specific.
This led the research team to develop a choice-based analytic framework to estimate non-motorized travel demand. The framework enables practitioners to evaluate bike and walk options relative accessibility – which is a measure of utility. Accessibility can be measured through GIS-based analysis to identify the total number of opportunities of a particular type (e.g., employment, retail, and health care) available to the traveler by a given mode. Building models around the concept of accessibility provides a solid basis for explaining choice behavior and its inclusion in travel demand models enables planners to investigate both land use and transportation facility factors.
The guidebook presents a range of both new and existing methods and tools that can be used to estimate non-motorized travel demand at different scales. One approach includes a new methodology based on land use/travel network accessibility relationships to estimate trips by mode. Renaissance used data from the Metropolitan Washington (DC) Council of Governments (MWCOG) for Arlington County, VA, to develop a method for estimating walk trip generation and mode split. The method uses geospatial overlay and network path-building procedures that are readily available in GIS to calculate measures of accessibility to or from any point by any mode and by type of attraction. By comparing the modal accessibilities, the model can estimate mode split and create walk trip tables by purpose. Since publication of the guidebook,