I've given this some thought previously and was interested in your comments. My conclusion was that autonomous cars are the future as it's virtually the only way you can have a reliable transport system allowing everyone to travel point to point via the optimum route.

There needs to be an incremental change for people to accept it though. Cruise control was the start. Newer cruise control systems can stay a constant distance behind the car infront. I don't know how reliable these systems are but I imagine they are relatively easy to acheive.

I imagine the next step as where your car purely follows the car infront, very closely behind. This would probably be easier than tracking the edges of a road. I accept it would only really be useful on motorways, but it could relatively simply get us most of the way towards autonomous cars and save a lot of accidents. Cars close together will have less air resistance so reduce fuel consumption. A long train of cars driving close together would radically increase the capacity of our current road network and reduce travel times.

The only difficulty is how do you ensure the lead car is trustworthy?