There's a system that can be retrofitted to the Chevy Volt and uses the existing vehicle systems to be as autonomous as you might wish for.
Mercedes distronic system controls the following distance and speed. Doesn't take much of a leap to add lane departure, blind spot recognition and infrared cameras, all of which are readily, and reliably, available.
The primary issue with the Tesla system in the US is that under run protection isn't mandated on lorries and their trailers are much longer with very different axle spacing. Both combine to cause issued for the low slung cameras on the Tesla in certain situations.
Also, if fully autonomous cars are to be allowed, then the developers are liable for any accidents caused by the car. Obviously that is a nonsense when you have a fleshy lump in the driver seat.