Vehicular Ad hoc NETworks, known as VANETs, are deployed to reduce the risk of road accidents as well as to improve passenger comfort by allowing vehicles to exchange different kinds of data, both between the vehicles themselves and potentially between the vehicles and the infrastructure. One of the major issues in VANETs is the need to improve safety information delivery over long distances. Hence, VANETs require efficient and stable routing protocols that can allow the safety information to be disseminated in a timely manner. We recently proposed TRPM, a TDMA-aware routing protocol for multi-hop communication based on a cross layer approach between the Medium Access Control (MAC) and the routing layers, in which the intermediate vehicles are selected according to their geographic position and the position of their time-slot in the TDMA scheduling frame. The main purpose of this paper is to analyze the efficiency of the TRPM protocol. To do so an analytical model is presented in which expressions are derived to calculate two performance metrics: the delivery delay and packet loss rate. In order to validate the mathematical model and the protocol, a comparison between simulation and analytical results is presented using the network simulator ns-2 and the realistic road traffic simulator MOVE/SUMO.