Car tourists may make some additional stopovers for sightseeing, meal, shopping, or leisure activities which is not originally planned to avoid becoming involved in the traffic congestion occurring on the roads returning home. The objective of this paper is to examine whether this induced stopover behavior exists and to empirically analyze the tendency of additional stopovers by departure time periods for returning home and level of traffic congestions. An analysis of route search data and GPS travel trajectory data collected by mobile car navigation application is conducted. The study results show car tourists tend to have additional stopovers when the departure time for returning home is early, and differences in the tendency of additional stopovers by congestion levels are observed, implying the impact of traffic congestion on additional stopover behaviors to some extent. The study results suggest the possibility of promoting additional stopovers in tourism areas for congestion avoidance by providing predicted near future traffic congestion and surrounding tourism information, which is beneficial to both tourism promotion and traffic congestion mitigation.