Public Transport Through Time and Space: Novel Indicators for Fare Policy Assessment

Governments and public transport (PT) companies worldwide are assessing the impact of PT fare innovations such as the Deutschlandticket or fare-free PT in response to promoting sustainable mobility and increasing ridership in a postpandemic world. However, to date, studies analyzing the impact of fare innovations on travel behavior have not fully exploited the spatial and temporal insights provided by novel smartphone-based tracking data. Our study addresses this gap by introducing four novel indicators that are simple yet insightful: (a) generalized cost of travel in fare associations, (b) travel distance per weekday and fare zone, (c) activity time per fare zone, and (d) travel direction per mode and zone of residence. The methodological relevance of these indicators for PT fare innovation assessment is discussed by applying these indicators to the case of the Deutschlandticket, an inexpensive, flat fare, nationwide PT travel pass, which replaces several local travel cards. We used multimonth, semipassive, smartphone-based tracking data from the Mobilitä.Leben study to assess the impact of the Deutschlandticket. The results showed that the effects of the Deutschlandticket exceeded purely monetary benefits and varied across fare zones, weekdays, and times of the year. This paper contributes to the assessment of the Deutschlandticket and expands scientific methods for assessing PT fare policy innovations. Spatial and temporal dimensions of activity time, trip distance, and trip direction are integrated into one assessment, creating new insights for urban planning and equity analysis. PT operators could use the indicators to optimize revenue distributions and adapt fare structures.