Travel behaviour and the 15-min City: Access intensity, sufficiency, and non-work car use in Toronto

One of the key travel behavioural assumptions in the 15-min City concept is that if daily necessities are nearby, residents would be encouraged to use slower but more sustainable modes, such as walking, cycling and public transit to reach these destinations, thereby reducing car dependence. This research explores non-work car use associated with the 15-min City concept in the City of Toronto, Canada. We first calculate transportation accessibility, or what we refer to as access intensity, to five categories of daily necessities (food, commercial, health, recreation, and education establishments) using walking, cycling, public transit, and driving. Next, these results are analyzed using a set of minimum access criteria to particular amenities within the different destination types to determine a set of binary access or sufficiency scores. Spatial patterns of accessibilities by mode show expected pockets of high and low access. However, further analysis of non-work trip rates using travel survey data suggests that increases in 15-min accessibilities by walking, cycling, and transit are associated with decreases in the use of driving for 15-min trips. In particular, driving rates decrease as sufficient walking, cycling, and transit access improves with the largest decrease associated with sufficient walking access to all five categories of necessities. This work offers important implications for sustainable transportation and land use planning as it appears that residents do use alternative and more sustainable modes when they are associated with sufficient accessibility to all categories of destinations.