Sustainable T ran sp o rta tio n In fra s tru c tu re Investments and Mode Share Changes: A 20-year case study of Boulder, Colorado.

摘要

This case study examines the benefits of sustainable transportation infrastructure investments toa city transportation system in terms of mode shifts. Building pedestrian, bicycling, and transitfacilities increases the capacity of a city's transportation system; the results suggest thatinvestments in such facilities are crucial to supporting transportation capacity while also enablingsignificant mode shifts from automobiles to walking, cycling, and transit.This paper reviews data from Boulder, Colorado, a city that has made substantial effortsto improve its multi-modal transportation infrastructure and services by investing in pedestrian,bicycle, and transit. This study examines the impacts of city-scale expansions of the scope andavailability of transit, bicycle, and pedestrian infrastructure and service with respect to modeshare changes. We first describe the relationship between the transportation infrastructureinvestments (supply) and mode share levels (demand); second, we draw research-informedconclusions between the two phenomena; and finally, we offer recommendations for citiesseeking to invest in multi-modal transportation systems.The city's transportation budgets for pedestrian, bicycling, and transit are examined inparallel with evidence from multiple community surveys and travel diaries to identify modeshifts from 1990 to 2009. Results suggest that substantial investments in new infrastructure andservices supporting pedestrian, bicycling, and transit have occurred in conjunction with stablepedestrian travel as population has increased, and substantial increases in bicycle and transitmode share.