Cars are ubiquitous and offer large and often highly visible surfaces that can be used as advertising space. Until now, advertising in this domain has focused on commercial vehicles, and advertisements have been painted on and were therefore static, with the exception of car-mounted displays that offer dynamic content. With new display technologies, we expect static displays or uniformly-painted surfaces (e.g. onto car doors or the sides of vans and trucks) to be replaced with embedded dynamic displays. We also see an opportunity for advertisements to be placed on non-commercial cars: results of our online survey with 187 drivers show that more than half of them have an interest in displaying advertising on their cars under two conditions: (1) they will receive financial compensation, and (2) there will be a means for them to influence the type of advertisements shown. Based on these findings, as well as further interviews with car owners and a car fleet manager, we discuss the require...