MODELS FOR ANTICIPATING NON-MOTORIZED TRAVEL CHOICES, AND THE ROLE OF THE BUILT ENVIRONMENT

摘要

This paper uses detailed travel data from the Seattle metropolitan area to evaluate theeffects of built-environment variables on the use of non-motorized (bike + walk) travel modes.Several model specifications are used to understand and explain non-motorized travel behaviorin terms of household, person and built-environment (BE) variables. Marginal effects ofcovariate effects for models of vehicle ownership levels, intrazonal trip-making, destination andmode choices, non-motorized trip counts per household, and miles traveled (both motorized andnon-motorized) are presented. Mode and destination choice models were estimated separately forinterzonal and intrazonal trips and for each of three different trip purposes, to recognize thedistinct behaviors at play when making shorter versus longer trips and serving differentactivities.The results underscore the importance of street connectivity (quantified as the number of3-way and 4-way intersections in a half-mile radius), higher bus stop density, and greater nonmotorizedaccess in promoting lower vehicle ownership levels (after controlling for householdsize, income, neighborhood density and so forth), higher rates of non-motorized trip generation(per day), and higher likelihoods of non-motorized mode choices. Intrazonal trip likelihoods rosewith street connectivity, transit availability, and land use mixing.Across all BE variables tested, street structure offered the greatest predictive benefits,alongside accessibility indices (for both motorized and non-motorized access). For example,non-motorized trip counts are estimated to rise 7% following a 1% increase in this variable, andwalk probabilities by 27% following a one standard deviation increase in this index at thedestination zone. Regional and local accessibility and density (of population plus jobs) variableswere also important, depending on response being modeled. Simulated model applicationsilluminate when and to what extent significant travel behavior changes may be witnessed, as landuse settings and other variables are changed.