Intelligent Transportation Systems (ITS) is an important research topic. One goal of ITS is to exchange information among vehicles in a timely and efficient manner. In the ITS research community, inter-vehicle communications (IVC) is considered a way that could achieve this goal without infrastructure support. An information network built on top of vehicles using IVC is a type of mobile ad hoc networks (MANET). In the past, many unicast routing protocols for MANET have been proposed. In these protocols, when a routing path breaks, they either locally or globally repair it. Because the topology of an IVC network changes very rapidly on the roads, an established routing path in such a network breaks very frequently. This phenomenon hurts the performance of applications running on an IVC network. In this paper, we investigate the effect of using roadside wireless repeaters on extending routing path lifetime in IVC networks on highways.