Measuring the direct and indirect effects of neighborhood-built environments on travel-related CO2 emissions: A structural equation modeling approach

Abstract

Intervening in the built environment is a key way for land-use and transport planning and related policies to promote low-carbon development and low-carbon travel. It is of significance to explore and recognize the actual impact of the neighborhood built environment on travel-related CO2 emissions. This study calculated the CO2 emissions from four purposes of trips, which were within the urban region, using Travel O-D Point Intelligent Query System (TIQS) and 1239 residents' travel survey questionnaires from 15 neighborhoods in Guangzhou. It measured the direct and indirect effects of built environments on CO2 emissions from different purposes of trips by developing structural equation models (SEMs). The results showed that for different purposes of trips, the effects of the neighborhood built environments on CO2 emissions were inconsistent. Almost all built environment elements had significant total effects on CO2 emissions, which were mainly indirect effects through mediators such as car ownership and trip distance, then affecting CO2 emissions indirectly. Most of the direct effects of neighborhood built environments on CO2 emissions were not significant, especially those from non-commuting trips. These findings suggest that in the process of formulating low-carbon oriented land-use and transport planning and policies, the indirect effects of the built environments should not be ignored, and the differences of the effects of the neighborhood built environments among different purposes of the trip should be fully considered.