Site specific propagation models for highly dynamic vehicle-to-vehicle scenarios become time consuming as the identification of visible surfaces must be performed independently for each transmitter location. Moreover the validation of higher order of ray interactions presents a significant computational overhead. This paper presents an efficient ray-tracing algorithm for vehicle-to-vehicle propagation prediction. The model presented in this paper extends a previous model that uses a pre-computed database of intra-visibility of walls and edges in the environment. The model computes the list of faces and edges that are directly visible to the mobile receiver. This visibility information is then used to reduce the image-tree thereby accelerating the ray validation. The paper also presents an efficient technique to compute diffuse scattered rays in a timely manner. The validation results show considerable time saving over previous models.