[VBprogrammer]

To me the solution to that is obvious and far better than the current status quo. The cars are all attached to a network and when an emergency service vehicle needs to get somewhere in a hurry there is a coordinated effort to move vehicles off the required route.

As things stand emergency vehicles have to cope with a reasonable minority of people who completely panic and actually impede their progress.

[zestyping]

This has to work even if network reception is weak or absent. You can't be certain that 100% of cars will receive the signal and get themselves out of the way in time.

[lwf]

Right, so don't use the network: broadcast a signed message on a band reserved for emergency services.

[tuatoru]

> This has to work even if network reception is weak or absent.

Or hacked maliciously.