Here's how I envision the gradual expansion of these technologies.
On the one hand we will have the open network; the public roads. Over the next two decades we'll see more and more automation integrated into our cars. Within 10 years we'll have the first vehicle-to-vehicle traffic negotiation devices show up. These will initially negotiate with the road signs, traffic signals and other vehicles. Within 20 years these devices will replace the signs and signals. The red light will be on our dashboard. The speed limit that currently shows on our GPS will have the force of law. At first the driver will be assisted by the automation technology. The computer will only take over when the driver is about to crash or run someone over.
Gradually the computer will take more and more of the driving role. It will park itself. It will brake at intersections. It will let off the brake when the light turns green (but the driver will press the gas to move forward). It will control the speed of the vehicle so the car can't go too fast. If an emergency vehicle approaches the car might pull off the road to let it pass.
In the meantime automation technologies will be integrated into private road and off-road networks. Golf carts will almost certainly be used in such a network. Standardization will allow industry to designate closed roads for moving goods between buildings and then within industrial parks. Then someone will want to connect the industrial park with the airport or seaport. Maybe they take a low use rail line and convert it to a closed road. Cities will probably close off downtown areas to non-automated traffic. People will hail a "cab" to get around downtown and use mass transit to travel outside the city.
As the technology advances the closed and open road systems will start to interact. You might drive to the airport but have your car drop you at the gate and then find a place to park itself. You go shopping and your car pulls up so you can load the groceries. In perhaps 30 years time the industrial system and the public system will be mature. Eventually we reach a tipping point where we just switch everything over to automated transportation.