Associations of local-area walkability with disparities in residents' walking and car use.

Research has examined spatial distribution of physical activity, mostly focusing on between-area differences by examining associations of area-level walkability measures with physical activity. Within-area distribution is also relevant, since larger disparities in physical activity within an area can contribute to greater inequalities in health. However, associations of within-area disparity in walking and walkability have been examined only at a large geographical scale (city level). This cross-sectional study examined associations of local-area walkability measures with within-area disparities in residents' walking and car use, using data collected in the 2009 South-East Queensland Travel Survey in Australia. For each Statistical Area 2 (SA2), we calculated disparity indices of the duration of walking and car use among participants aged 18-84 years, using Gini coefficients. Linear regression examined associations of the disparity measures with population density, street connectivity, and Walk Score. Analyses were conducted for 196 SA2s, which contained 15,895 participants. Higher walkability was associated with lower levels of disparity in walking and higher levels of disparity in car use, regardless of the measures used. Each one-SD increment in Walk Score was associated with a 0.64 lower SD in walking disparity and a 0.50 higher SD in car-use disparity, after adjusting for covariates. The associations remained significant after further adjusting for car ownership. Higher walkability is known to be associated with more walking and less car use. This study extends previous knowledge by showing that higher local-area walkability can be associated with less inequality in residents' walking and higher diversity in their car use.