UC Davis Institute of Transportation Studies

Changes in travel behavior of regular commuters during the temporary closure of Interstate 5 in downtown Sacramento, California were investigated by analyzing “temporary” vs. “longer-term” changes in the frequency of drive-alone commuting. A similar proportion of the sample increased driving alone (23%) as decreased (22%). Those who increased driving alone were substantially more likely to make this change a regular, longer-term, behavior (83%) compared to those who decreased (52%), increasing emissions. About 61% of the sample did not change their driving alone in either direction. Numerous variables are considered to be potentially important predictors of changes, including socio-demographic traits, environmental and travel attitudes, and land use characteristics. The influence of the freeway closure is also explored. Discrete choice models of the changes are estimated, and characteristics associated with making positive or negative, temporary or longer-term changes are identified. Important land use characteristics include access to amenities such as grocery stores and schools in the vicinity of home and work locations. Additional characteristics that are important factors in the changes modeled include the background commute patterns, occupation types and attitudes towards transportation and travel.