Publication Detail

Trip Generation for Smart Growth Projects

UCD-ITS-RP-14-137

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Suggested Citation:
Schneider, Robert, Susan L. Handy, Kevan R. Shafizadeh (2014) Trip Generation for Smart Growth Projects. Access Magazine (45), 9 - 15

California encourages developers to pursue urban infill projects in order to achieve a variety of infrastructure efficiency and environmental goals. Since they are already surrounded by established developments, infill projects provide better opportunities for walking, bicycling, and public transit, and they encourage fewer automobile trips than new suburban developments. Nevertheless, developers often meet resistance when proposing infill projects. Neighbors worry, "The development will increase traffic and make it difficult to park." Public officials warn, "The developer must pay a fair share of the roadway improvements that are needed to serve the additional cars and trucks." To address these concerns, developers must complete a transportation impact assessment (TIA), required by federal, state, and local laws. If an assessment predicts that an infill project will generate more automobile trips than local streets can handle, local officials may require the developer to build or pay for wider roads, additional turning lanes,or larger parking lots. By accommodating more cars and trucks, these requirements counteract potential reductions in auto travel. In addition, the added costs make some infill projects financially infeasible, causing developers to scrap infill proposals in favor of suburban greenfield development. Why isn’t this process working? The answer is related to the traditional TIA approach. The California Department of Transportation (Caltrans) asked our UC Davis research team to delve into TIA trip generation practices, and in response we created an adjustment tool that improves the accuracy of estimating automobile trips in urban areas and should make it easier for developers to get infill projects approved.

Key words: Infill development, environmental impacts, social impacts