In this paper, we propose a Trust Model for VANETs. It is a combination between centralized and distributed cooperation between vehicles and infrastructure to achieve the selection of the trustiest node as a Group Leader. The proposed model is based on different metrics to analyse the behaviour of the vehicles in the group while preserving the privacy of the participants and maintaining low network overhead. The evaluation of the proposed trust model is done by simulations using GrooveNet. Results show the efficiency of the proposed model to select the trusty vehicles