How autonomous vehicles (AVs) may impact passengers’ travel time use is not well understood. Because AVs require minimal attention, users may find themselves free to engage in new activities and use their travel time more effectively. If AVs improve the quality of activities conducted while traveling, passengers may experience reduced value of travel time savings, leading to more and longer trips and thereby increasing congestion and emissions. On the other hand, if people are able to more effectively engage in productive work activities while traveling, overall societal productivity may increase with the introduction of this new technology. Despite the large and varied implications, there has been little systematic investigation into how people will use their time in AVs. This paper presents the results of an online survey conducted among 1,782 Singapore commuters. The authors use several metrics of time use effectiveness to analyze the activities which people currently engage in on their commute, and report respondents’ attitudes towards time use both presently and in AVs. The authors also test whether respondents would significantly change their commuting activities if they were instead to commute using an autonomous mobility-on-demand service. The authors' findings suggest automobile commuters are more likely to engage in leisure activities in AVs, while public transit riders are likely to conduct fewer activities overall, but to participate in more social activities such as talking face-to-face. AVs therefore appear to allow for more effective leisure done during the commute, but may not lead to gains in productive work done while traveling