Private car use is a major contributor to global and local environmental pollution in the form of carbon emissions, poor air quality, excessive noise, building vibrations and traffic congestion. One way of reducing reliance on the private car is to promote forms of active travel (walking, cycling and running) and the use of public transport through behavioural change. This chapter outlines a theoretical and empirical approach to understanding commuter travel behaviour that integrates insights from social-psychological research on travel behaviour with sociological framings of everyday mobility. It demonstrates the ways in which commuting dynamics can be understood through adopting Bayesian statistical techniques, which assist in identifying the factors that influence decision making and the probability of travel mode shift on a daily basis. The research reveals the potential of targeted approaches to generate incremental shifts in travel behaviour, alongside significant structural barriers for encouraging more radical shifts in mobility.