To deter dangerous driving, we recently proposed an automotive telematics system, which displays safe driving points and rankings to a driver in real time. In this study, we tried to enhance the effectiveness of the system by adding an individual or team competition. Effect measurements of these functions were carried out on a driving simulator using a between-subjects design under three conditions: original ranking, individual competition, and team competition conditions. The experimental route was three lanes and about 6.7 km long. Safe driving points were calculated by the value of the following time and acceleration. After the experiment, we analyzed the following time, rapid acceleration, sudden deceleration, and the number of lane changes. Moreover, questionnaires were used to analyze impressions of the system. When the results were comprehensively examined, although all the conditions considerably enhanced sufficient following time as well as gradual accelerations and decelerations, the individual competition condition had the largest effect. The scores of the questionnaires showed that the participants seemed to be encouraged most by the driving scores and the competition.