Vehicular ad hoc networks as a subset of mobile ad hoc networks have recently received considerable attention. In such networks, demands which are based on disseminating information from a source to vehicles in the road are increased. Various applications that range from safety support to entertainment for passengers developed for VANETs rely on data dissemination from an information source to many vehicles on the road. Mobility is the distinguishing feature of vehicular networks, affecting the evolution of network connectivity over space and time in a unique way. Connectivity dynamics, in turn, determine the performance of networking protocols, when they are employed in vehicle-based, large-scale communication systems. In this survey, we investigate the problem of distributing a large amount of data to a sparse vehicular network from roadside units, using efficient vehicle-to-vehicle collaboration. The basic idea is to have a roadside unit give data to moving vehicles in its communication range. Vehicles carry and forward the data to vehicles get close to the roadside unit. Due to the highly dynamic nature of the underlying vehicular network topology, we depart from architectures requiring centralized coordination, reliable MAC scheduling, or global network state knowledge, and instead adopt a distributed paradigm with simple protocols. In other words, we investigate the problem of reliable dissemination from multiple sources when each node in the network shares a limited amount of its resources for cooperating with others. By using rateless coding at the road side units and using vehicles as data carriers, we describe an efficient way to achieve reliable dissemination to all nodes (even disconnected clusters in the network). In this research, communication between vehicles is performed using short range communication. We explore an opportunistic approach for information collection, in which a vehicle obtains information about resources from encountered vehicles. We explore vehicles as mobile storage devices. We then develop a method to keep the density of the rateless coded packets as a function of distance from the RSU at the desired level set for the target decoding distance. Based on our simulations, the decoding probability for a vehicle gets close the roadside unit is quite acceptable. We investigate various tradeoffs involving buffer size, maximum capacity, and the mobility parameter of the vehicle s. Limited buffers in the carrier vehicles engender the new obstacle for information dissemination. Since the relevance of data for a receiver decreases with increasing distance to the location where the data was originally generated, as the distance between the carriers and roadside unit increases, they make decision to drop some of their packets. Keywords Vehicular Networks, Road Side Unit, Limited buffer, Packet dropping from the buffers, Rateless Coding