The influence of the built environment on mode choice – evidence from the journey to work in Sydney

The Five Ds of the built environment – density, land use diversity, pedestrian oriented design, destination accessibility and distance to transit – are suggested by Ewing and Cervero (2010) as the built environment factors that can reduce car use in favour of public transport, walking and cycling. This paper examines the strength of these effects by analysing whether built environment factors can be shown to influence journey to work transport mode share in Sydney. GIS and multivariate regression analysis of mode share and built environment data in 1553 Travel Zones across the Sydney metropolitan area shows that each of the Five Ds of the built environment are statistically significant determinants of mode share for the journey to work, with the exception of pedestrian oriented design. The degree to which each built environment factor influences mode share is expressed as an elasticity, allowing the strength of each factor to be compared. Destination accessibility by public transport and population density appear to be the most important factors. However the elasticities of the Five Ds were much lower than the control variables of car ownership, income and workplace location. Results suggest that the design of local urban areas can influence non-car mode share by residents. This gives support to planning controls that support transit-oriented design. However, the effect of the built environment should not be overstated and consideration should also be given to more strongly associated variables such as car ownership and workplace location.