Columbia River Crossing (CRC) staff, with input from the CRC's Pedestrianand Bicycle Advisory Committee (PBAC), developed a methodology for forecasting year 2030 pedestrian and bicycle travel demands for an improved non-motorized facility proposed for the replacement Interstate 5 (I-5) Bridge across the Columbia River. Forecasts took into account three primary factors related to pedestrian and bicycle demand: existing and future land uses, percentage of trips by mode, and walking and bicycling trip lengths. During peak summer conditions in 2007, about 80 pedestrians and 370 bicyclists crossed the I-5 Bridge daily. Many other pedestrians and bicyclists are discouraged from doing so because of the existing non-standard facilities on the bridge and connecting multi-modal infrastructure. Future pedestrian and bicycle trips over the I-5 Bridge were forecast using a variety of data, including mode share data from the US Census, information from local travel surveys, results from a bicycle trip study conducted by Portland State University, and travel characteristics associated with the Hawthorne Bridge, the heaviest traveled bridge by pedestrians and bicyclists in the region. Average travel times by mode were converted into trip distances bymode, creating a matrix of pedestrian and bicycle mode shares by trip length. Future scenarios, developed for sensitivity testing, considered the forecasted number of trips from the regional travel demand model and factored them by the respective pedestrian and bicycle mode share percentages. The results were a range of daily pedestrian and bicycle forecasts, all of which showed a substantial increase in travel demand.
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