Transport pricing and infrastructure investment are widely seen as essential elements in policy packages aiming to address transport challenges. However, their respective and collective causal influences on travel behaviour have not been sufficiently examined. In this study, we investigate the effects of vehicle quota control and transport infrastructure investment on vehicle travel in Singapore, with a pseudo panel created from three repeated cross-sectional household surveys. We find that vehicle quota control has a substantial influence on vehicle usage by constraining car ownership. However, this mitigation effect might be partially offset by the higher car usage among car owners who want to make more out of their investment in private cars, confirming the existence of sunk cost effect in transport pricing. Careful design of vehicle quota control policies is thus necessary to avoid the overuse issue. We also find that rail transit network expansion reduces vehicle usage, while expressway network expansion increases it. An integrated approach that combines pricing measures to discourage vehicle usage and public transport investment to provide alternatives to driving may be more effective in achieving transport sustainability.