Wherever we are, we assume that we will be able to access the network to read our email, visit a website or download our favorite music, and to do this we often rely on the cellular infrastructure, especially when we are on the streets, walking or driving. With our mobile devices in our hands, we perceive network access as an ubiquitous service. However, we often overlook that the place where many people spend the majority of their mobile time, the car, is a lot more than a means of transportation. Not only are cars an extremely advanced mechanical tool, they are also equipped with cutting-edge communication and sensing technology. For the first time, users are not carrying their mobile computing device with them but are being carried by the device itself, and at ever increasing speeds. This change encompasses more than a simple size difference: it relaxes some of the constraints of mobile networks, and defines a set of new ones.