Impact analysis of positive utility and built environment on car use for non-work trips: an ensemble approach

Although the Positive Utility of Travel (PUT) has been well discussed in the relevant literature, there remain research gaps in practice, particularly regarding how this utility can be effectively incorporated into conventional transportation models. Additionally, there is a need for further exploration of how the built environment influences car use for non-work trips with different levels of intrinsic utility. In this regard, distinguishing trips by the context of destination and/or purpose (as an approach in previous studies) is not a perfect method, as the intrinsic utility of trips may be different for each trip regardless of these contexts. To address this gap, we modified the conventional travel survey and collected the required data in fall 2022 and spring 2023 from 1170 respondents residing in Shiraz, Iran. Based on a series of questions about each reported trip, two types of travel were recognized by fuzzy C-means clustering: Low PUT and High PUT. Interestingly, about 56% of non-work trips were undertaken both to reach a destination and to travel itself. Furthermore, using a novel ensemble analysis approach, we found that five variables, including population density, block density, outdoor space proximity, positive attitude toward transit and family size, significantly affect car use for both types of travel. However, the importance of these variables differs for different trip types. According to the Multiple Criteria Decision Making (MCDM) results, motorcycle ownership and outdoor space proximity are the most important variables for predicting car use for trips with low PUT, while family size and population density are the most influential variables for explaining car use for trips with high PUT.