Understanding travel time uncertainty impacts on the equity of individual accessibility

Most current accessibility equity studies ignore travel time uncertainties. This study investigates the travel time uncertainty impacts on the equity of individual accessibility. Travel time distributions of the road network and mobility data for a large number of individual samples across the entire study area are extracted using comprehensive big datasets of taxi trajectories and mobile phone tracking data. Two reliability-based individual accessibility measures are proposed to evaluate individual accessibility by explicitly considering individual's on-time arrival probability concern for activity participations. The proposed measures are further applied to quantify travel time uncertainty impacts on the equity of individual accessibility to shopping services. Results of this study demonstrate the capabilities of using spatiotemporal big data to examine the equity of accessibility in a disaggregated individual level. The results also suggest that travel time uncertainties have negative impacts on accessibility of all people groups, but more serious impacts on disadvantaged people groups with a lower accessibility level.