Does a short journey get me to the food bank? An empirical study on fare-based public transport accessibility and its implications for social equity

Fares are a critical barrier for low-income earners towards using public transport (PT). While most literature focuses only on travel time and distance, we introduce the novel indicator of ‘fare accessibility’.

Fare accessibility extends Hansen Accessibility by incorporating pay-as-you-go costs as impedance, counting the amenity destinations reachable within a €2.30 ticket. To assess distributional equity of fare accessibility in the Greater Hamburg region (HVV) we use Lorenz curves. Furthermore, we employ spatial regression models to predict its variation based on eight factors, including PT service level, purchasing power and car availability. We calculate models at three spatial levels (municipality/PT stop/500 m grid) to discuss the influence of the Modifiable Area Unit Problem. In doing so, we assess the sensitivity and suitability of this indicator beyond established metrics.

Fare accessibility shows a significant relationship with centrality at all spatial levels. A single ticket offers the highest accessibility in densely-populated regions with a high PT service index, short travel times, low purchasing power and low car availability. While this hints towards using existing indicators at a regional level, fare accessibility helps to identify local deficits e.g. by quantifying the population without access to a food bank (which we understand as exemplary for any kind of destination). Overall, fare accessibility is less equally distributed than PT service and car availability; the HVV residents holding around half of the purchasing power are not able to reach any destination on a €2.30 budget, which is supposed to connect everyone to the next shopping centre. The share is dependent on spatial resolution, while a finer level improves sensitivity to inequity. With the Modifiable Area Unit Problem in mind, the stop level offers a suitable compromise between precision and computational capacity. Moreover, stop level analysis is compatible with practical PT planning.

Overall, fare accessibility emerges as an informative indicator for planners and policymakers. It can be expressed for numerous amenity destinations, offer insights into the daily struggles faced by low-income earners, and provide a tool to assess and improve accessibility for those most in need.