The Relationship between the Evaluation of Public Transport Services and Travel-Based CO2 Emissions from Private Transport Modes in Regional and Metropolitan Areas in Japan

Promoting public transport use is expected to contribute to reducing CO2 emissions in the transport sector. Using Okayama City and Central Tokyo as representative case studies of regional and metropolitan areas in Japan, this study examines the impact of the evaluation of the 'hard' and 'soft' attributes of rail and bus services on the overall evaluation. This study then explores the relationship between the overall evaluation and usage frequency of rail and bus services, as well as the relationship between the usage frequency and travel-based CO2 emissions from private transport modes. Furthermore, this study investigates whether the emissions cause differences in the evaluation of the 'hard' and 'soft' attributes of public transport services. The findings suggest prioritising an improvement in 'hard' rather than 'soft' attributes in order to reduce emissions through the use of public transport in regional areas. However, in metropolitan areas, no relationship was found between the evaluation of public transport services and emissions, presumably because of the lower ownership rate of private cars that residents can use freely and the markedly higher level of rail and bus services. This study provides a methodological reference for analysing the potential to reduce travel-based emissions from private transport modes by enhancing public transport service contents.