> They suggested transponders in each car that would give the ID to a police officer if he pointed a "gun," similar to a radar gun, at it. They said that other possibilities included readouts of speed, exhaust emissions, etc.
>
> While it was doing all of this it could check to see if the car was on a stolen list, or had outstanding traffic warrents.

All of these are public information anyway. Anyone could legally find out this stuff about your car, such a device would just speed up the process for police officers.
Models sold to the public might restrict the information given to what is legally available to Average Joe/Jane (so it's not invading privacy). Police models would give the police officer what he needs and an easy way to act on it.

That sounds like an improvement to me, with an added bonus of less restricted car designs.

NormalAsylum