The importance of walking for public transport – just the first and last mile?

Policies for public transport and walking support sustainable mobility in urban contexts. While public transport necessitates walking, policies that integrate both modes in a cohesive manner remain scarce. To raise awareness and illustrate the symbiotic relationship between walking and public transport, we analyse data from 7,919 public transport (PT) trips comprising 38,933 trip legs. To address the challenge of diverse PT travel chains, a cluster analysis identifies four distinct PT trip types within the data. They vary in their temporal composition and mode usage across the door-to-door trip leg sequence. Two shorter, everyday PT trip types account for 89% of trips, with nearly all access provided by walking. For these trips, travellers spend 48% and 64% of their total travel time as pedestrians within the public urban realm, which includes walking, waiting and transferring. For the 10% of longer trips involving faster PT modes, walking remains the dominant access mode at the home end of the trip, and the share of bike and car usage exceeds 50% only at access distances greater than 1.5 kilometres. Access at the activity end of these longer PT trips is exclusively on foot, with travellers spending 32% of their total travel time as pedestrians. A small proportion (1.3%) of PT trips involves modes other than walking for access at the activity end of trips, with 22% of total travel time spent as pedestrians. Specific transfers from bike or car to PT require walking between parking facilities and PT stops or platforms. Walking times of 1.5 to 2.4 minutes for longer PT trips underscore the importance of short walking distances as a prerequisite for accessing PT via other modes. This points to both the potential and the limitations of integrating additional modes into PT trips. The data and methodology used in this study provide generalizable insights into the role of walking in PT trips. Overall, the results underscore the synergistic potential of integrated policies for walking and public transport, which holds true across all 12 urban contexts in the dataset.