Telematics service is a rapidly evolving mobile commerce service in the early stages of its diffusion. This study examines consumer preferences for transport telematics services over time in terms of service features and purchasing time by conjoint analysis and the rate of time preference (RTP) method. Our empirical results prove that an upgraded navigation-traffic information service and the vehicle relationship management (VRM) service are the most important factors for both current and potential consumers and that timing of these services has a negative impact on consumer preferences. (c) 2004 Elsevier B.V All rights reserved.