A typical task in many applications for vehicular networks is to disseminate information to a subset of vehicles on a highway. In this work we describe a theoretical estimation for the average number of such independent tasks that can be sustained concomitantly in ad-hoc vehicular networks using contention free medium access and a fixed number of wireless channels. We call this measure the vehicle to vehicle (V2V) capacity of the network. Using our estimation, we perform an analysis of the V2V network capacity under different highway traffic conditions and scenarios. A surprising conclusion drawn is that congestion actually determines an increase in capacity. Based on these observations, we propose a simple strategy that can increase the capacity by filtering communication tasks with length greater than a certain threshold which can be determined numerically.