Theoretical understanding and methodological challenges in accessibility assessments, focusing the environmental component: an example from travel chains in urban public bus transport.

PURPOSE: In order to increase the theoretical understanding of the concept of accessibility, this paper reports the results from an exploration of methodological difficulties inherent in systematic accessibility assessments of single persons' travel chains in urban public bus transport. In addition, Special Transport Service (STS) travellers' perception of environmental demands in public transport are reported. METHODS: This study was designed to explore the environmental component in accessibility problems systematically. Twenty persons entitled to STS were recruited in order to travel by low-floor bus, Service Route Traffic (SRT) or STS. Two different methods were chosen. Critical incidents were collected during participant observation, and by means of a pilot instrument based on the Enabler Concept independent environmental assessments were performed. RESULTS: Not all environmental details registered during the participant observations were in agreement with the independent environmental assessment, and different reasons for the disagreements were reported. In addition, participants travelling by STS gave information about what hindered them from using conventional public transport. CONCLUSIONS: The theoretical understanding behind accessibility assessments has benefited from the methodological challenges mapped out in this study. In order to interpret accessibility, the individual perspective as well as the population perspective are necessary, which means that complementary methods are needed.