In recent decades, cities have become increasingly motivated to invest in infrastructure that supports multimodal options like walking, biking and public transit. Trip generation, the first step in conventional four-step forecasting models, is a central figure in determining how those investments are made.
However, when considering pedestrian and bicycling travel, the current practice is usually to either leave those trips out of the model altogether, or to simply present them as a mode choice option that is not analyzed further. In short, cities are car-centric.
Without reliable trip generation rates for anyone but drivers, an accurate transportation impact is difficult to predict. Certain land uses will draw far more walkers, cyclists and transit riders than drivers. Cities lack enough information to strategically plan for multimodal investments.
Researcher Kelly Clifton of Portland State University (PSU) has worked on an extended series of projects developing new tools to address this knowledge gap. PSU is home to the National Institute for Transportation and Communities (NITC) – a University Transportation Center that focuses on improving the mobility of people and goods to build strong communities.