Ricerc@Sapienza

This paper is a part two of a study investigating the relative importance of the built environment, sociodemographic,
and attitudinal factors on mode choice. A semi-experimental approach that aims to
measure causal effects of the built environment is utilized. This paper reports spatial analysis, survey and
modeling results for San Francisco, CA, USA and compares the results with a previous similar study in
Rome, Italy. Results reveal that the local street network’s integration is important in both cities and that in
both cases built environment seems to have higher impact on mode choice than attitudes and sociodemographic
factors. Built environment is especially impactful when diversity, design quality, density and
syntactical accessibility are combined. In San Francisco willingness to spend time walking, biking or taking
transit is lower than in Rome, and residents are more sensitive to concerns about safety and security. Work
travel is more affected by demographic and attitudinal factors in San Francisco than in Rome implying
that in San Francisco, nonwork travel behavior may have slightly higher potential to respond positively to
improvements in the built environment than work trips. In Rome, peer pressure, cost sensitivity, and
probiking attitude can compensate for lack of some built environmental characteristics, but not in San
Francisco, where only protransit attitude has this effect. Moreover, lack of any built environmental
characteristics reduces the possibility of sustainable mode choice more dramatically in San Francisco
pointing to the higher importance of investments on improving the built environment rather than
marketing efforts to change attitudes.