The world as we know it now is driven by wireless technologies. Most people have cellphones, we have wireless internet connections, and there are a lot of different technologies that are in use there. Having vehicles that are able to talk to each other or are able to communicate with the road way is nothing new, it's the next logical progression that we have.There are cars already that act as hotspots and communicate on the cellular network and they provide Internet access to the passengers of the vehicle. So vehicle-to-vehicle technology is just allowing two vehicles that are within proximity of each other the ability to communicate. This is something that is not difficult to do, we have short range personal networks like Bluetooth, we have dedicated short range communication, there's even cellular providers who are saying that we don't need to have the vehicles with each other over an add-hock network but perhaps they still communicate through the infrastructure and when they hit on of the base stations it comes back to communicate with one of the vehicles that are in close proximity to it.
source:http://www.livescience.com/52875-the-future-of-driverless-vehicles.html
