The rising demand for mobility in the 21st century creates a challenge for interdisciplinary researchers. As a result, the number of papers devoted to the application of agent-based technologies in the transportation engineering domain has grown enormously. However, there is still a need for modelling platforms that are capable of exploring the in- uence of different psychological factors on individual decision-making. By utilising our current mobility simulator - BedDeM, we propose an experimental method to test and investigate the impact of core determinants in Triandis' Theory of Interpersonal Behaviour on the usage of different transportation modes. Comparing the results with a calibrated population of Swiss household data, we conclude that Intention and Af- fect have a positive effect on the usage of private vehicles, while Habit and Social factors can encourage people to travel with public or soft transportation modes.