Transport is responsible for a quarter of total carbon emissions as reported by the COP26 summit. Public transport travel is widely known to have less environment impact, but how the awareness influences traveller’s choice of mode(s), whilst considering the interplay of a wide range of other factors, is under-researched thus far. The study aimed to gain understandings of commuters’ travel with attention to their attitudes towards the environment, accessibility, convenience, and safety. A questionnaire was designed, and 730 useful responses were collected to provide a representative sample of the Bangkok Metropolitan Region population. Descriptive analysis led to an understanding of the commuter population characteristics with private car followed by urban rail being the most popular. Principal component analysis (PCA) was implemented to reduce 20 attitudinal statements into an uncorrelated set. The four components retained from the PCA were labelled as “impact of travel behaviour”, “willingness to purchase low-polluting cars”, “safety and convenience”, and “attitudes to private motorised transport”. The component scores were analysed with attention to the respondent’s gender, age, and self-defined commuting transport mode. Age and mode identity firmly influenced the component especially active transport users. This research has provided decision-makers with scientific evidence for more sustainable transport options.