If cars could talk to one another, what could (and should) they say?

At Mobile World Congress, Ford Motor executive chairman Bill Ford (s f) tried to elevate the discussion of the connected car beyond the infotainment system. In a speech on Monday, Ford outlined a future of 4 billion cars that don’t just use wireless links to tap into music, media and navigation, but communicate with one another as peers, sharing information such as their speed, direction and the moment they brake with all of the other vehicles on the road.

Such technology could be used to create harmony on the highway, Ford said, sorting vehicles into the optimal spacing pattern and allowing them to automatically decelerate when cars miles down the highway warn of impending traffic. It will be the closest thing the industry has ever developed to autopilot, Ford said. Furthermore such ad hoc vehicle networks could be integrated with other transportation networks, from pedestrian cross-walk systems to connected bicycles, making your car a single node in a giant grid of multi-modal transit intelligence.

Ford’s point is that modern car is already one of the most sophisticated collection of sensors and computing power consumers own, but so far none of those capabilities have been networked—they function solely within the confines of the vehicle. Networking vehicles through peer-to-peer Wi-Fi connections would bring that intelligence out of isolation. In all, Ford painted a very bright picture of how networking technologies could change the face of transportation. But the future he predicts could also be a very scary one.

There’s a good reason in-car networking has focused primarily on entertainment and navigation. Giving the network access to the more sensitive workings of our cars’ drive computers could wind up being privacy and safety nightmares. Sharing real-time data about your car’s current direction and speed to hundreds of other vehicles is going to be disconcerting to many, but what happens if the drivers of those vehicles or anyone with a Wi-Fi receiver can access that same data? Could that connection be used to track cars as they traverse the highways?

What if the network is hacked? Such networks aren’t just transmitting information, they’re acting on it. Introducing false vehicle data into the stream could cause our cars to respond to phantoms, swerving to avoid vehicles that aren’t there and braking for gridlock that doesn’t exist.

Security will obviously be a huge part of any future standard involving interconnected cars. Not only would automakers need to ensure that only vehicles could access and transmit data through the network but also that none of it was stored or somehow passed on. But if Ford can convince other automakers and regulators to back such an idea, it would not only change the way we drive, but the way we approach wireless networking.

Ford is asking us to sign a social contract of sorts. We’re essentially putting part of cars into the public trust, allowing the government or some entity charged with managing the system to use our vehicles as relays within a huge mesh network of interconnected, distributed yet autonomous nodes – all of which are constantly moving and reconfiguring. Technically those same principles could apply to the cellular network as well. Instead of connecting to a tower, devices would link to one another, daisy chaining their way back to a tower. Such a set up could infuse enormous amounts of capacity into any mobile networks, whether composed of handsets or automobiles. But we would also have to come to terms with the concept that our phones and are cars are not completely our own.