ABSTRACT
VANETs, which are a form of MANETs, have some distinctive properties compared with MANETs which influence in the attempts of construction of trust models for VANETs. Highly dynamic network, frequently changing topology, and ephemeral nature of the network connectivity are the key nature of these networks. As no vehicle can establish long-term connectivity with any other vehicle, the trust metric to a vehicle is valid for a short period. Another characteristic of these networks is interaction with high number of peers within a very short period. A vehicle may get connected and disconnected with thousands of other vehicles depending on the traffic, speed, and location it is crossing over. Some important services of VANETs are safety warnings, traffic updates, route suggestions, and so on. Time freshness and location relevance as well as trustworthiness of these services are very important for taking right decision at the right time; otherwise, it may get into accident, may get into congestion, or follow a wrong route.
