Time dependent accessibility

AbstractMany place based accessibility studies ignore the time component. Relying on theoretical frameworks that treat distance between two fixed points as constant, these methods ignore the diurnal and seasonal changes in accessibility. Network distances between two nodes are dependent on the network structure and weight distribution on the edges. These weights can change quite frequently and the network structure itself is subject to modification because of availability and unavailability of links and nodes. All these reasons point to considering the implications of volatility of accessibility of a place. Furthermore, opportunities have their own diurnal rhythms that may or may not coincide with the rhythms of the transportation networks, impacting accessibility. Using the case of transit, where all these features are readily apparent simultaneously, I demonstrate the volatility in accessibility for two counties in North Carolina. Significant diurnal changes are observed in quarter of the locations and in the rest the changes are minimal mostly because of low levels of transit accessibility. I argue not for minimizing the volatility, but for acknowledging its impacts on mode choices, location choices and therefore on spatial structure of cities