How about giving cars each a fast wireless node that can be configured as a auto-discovery mesh network, and then allowing the nodes to combine their computing power into a dynamic mobile grid?

Perhaps such a system would have enough local number-crunching power to do collision-avoidance, traffic management, etc, as well as bouncing a network connection along lengthy stretches of highway with no external infrastructure.

Now that would be pretty cool :)

--Michael Okun, AKA Anonymous Coward