In order to investigate how public transport should be improved to appear attractive to car users, this study develops and tests an internet-based experimental simulation of travel mode choice dependent on the complexity of daily activity agendas. The results for 75 students taking part in the experimental simulation are compared to the results of a survey of another 69 students taking part in a pilot study. Students in both groups were frequent car users. The results of the survey showed that higher costs of car use and greater perceived difficulty to use public transport decreased intention to use the bus for the commute to the university. In the experimental simulation high access to bus stops increased bus use and reduced car use but less for a busy daily activity agenda when the car-use costs are low. The results highlight the importance of focusing on tradeoffs between increasing car-use costs and improvement of public transport.