Making Streets into Complete Streets: An Evidence Based Design Manual

The predominant approach toward street function on major roads in the United States is to emphasize mobility and throughput of vehicles. The \"Complete Streets\" movement challenges some of this paradigm, emphasizing that streets should accommodate multiple modes of travel and should often be considered destinations themselves. Often, efforts to transform streets into complete streets (or from mobility-based to accessibility-based designs) face resistance from both professional communities of traffic engineers and from the public that their design will reduce throughput and flow of vehicles. Complete streets advocates, in some cases, counter that while their designs often create pedestrian and cycling space…

The predominant approach toward street function on major roads in the United States is to emphasize mobility and throughput of vehicles.  The \“Complete Streets\” movement challenges some of this paradigm, emphasizing that streets should accommodate multiple modes of travel and should often be considered destinations themselves.  Often, efforts to transform streets into complete streets (or from mobility-based to accessibility-based designs) face resistance from both professional communities of traffic engineers and from the public that their design will reduce throughput and flow of vehicles. Complete streets advocates, in some cases, counter that while their designs often create pedestrian and cycling space from areas that were previously occupied by automobiles, that throughput is often not impacted and that flow can actually improve.

One example of this conflict is in the concept of the \“Road Diet\”, where a four-lane road (two lanes in each direction) with no median or bike lanes is turned into a two-lane road (one lane in each direction), a center turn median and two bike lanes.  Removing two automobile travel lanes seems like it would reduce automobile throughput, but supporters of Road Diets believe that the increased flow achieved with left turning vehicles using the center median actually maintains or improves upon previous throughput numbers because flow is improved on the through lanes.

This proposed technology transfer project is to document a variety of existing and implemented examples of Complete Street improvements from around the country, visually document their design and context, and compare actual throughput in order to create a design toolbox for transportation planners and traffic engineers across the country.  The result will be a print and web-based reference guide for transportation planners and traffic engineers to use to determine the best designs for retrofitting streets based on differing right of ways and desired ADT.  Complete Streets policies are being adopted all across the country, but local officials have few documented guidebooks to help them think about how to retrofit streets based on best practices.  This technology transfer project intends to fill this gap.

*This proposal was previously submitted and received high peer reviews, but with a desire to see a searchable web-version of the results and to better align the travel budget with travel needs.  This proposal incorporates both recommendations.