Greenhouse gas emissions and urban form: Linking households’ socio-economic status with housing and transportation choices

The main purpose of this research is to provide new insights for reducing greenhouse gas (GHG) emissions linked to transportation, furthering our knowledge on linkages between urban form and economic constraints, travel behaviour, and ability-to-pay of households based on residential choices and property ownership statuses. With Quebec City (Canada) as a case study, it combines an origin-destination (OD) survey, population census data and land use records for 2006 and rests on a series of structural equations models developed at the grid cell level (3,892 cells), which allows for testing for both direct and indirect effects of urban form, accessibility and socio-economic attributes on GHG emissions, households’ transportation and housing financial burdens and motorization rate. As expected, findings suggest that GHG emissions increase with higher incomes (and education), but mainly for homeowners. Tenants displaying a high expenditure-to-income ratio for housing tend to stay close to the city centre (and jobs), thereby minimizing their overall expenditures for transportation while lowering GHG emissions. Potential accessibility by car promotes urban sprawl, thereby contributing to increased GHG emissions. In contrast, increasing residential density and land use mix while providing a better walking access to jobs and local shops tends to favour active transportation, leading to a significant reduction in GHG emissions.