Caltrans had pilot program in the mid-1990's running self driving cars that used magnets embedded in the road. They would run "caravans" of five-ish vehicles dr

Caltrans had pilot program in the mid-1990's running self driving cars that used magnets embedded in the road. They would run "caravans" of five-ish vehicles driving almost bumper to bumper. This was tested on the car pool lanes on sections of a highway between los angeles and san diego. This was a partnership between caltrans, the college of engineering at uc berkeley amongst others. Unfortunately I can find any readily available links, but all of the data should be public. I'm only aware of this because I worked w/ some of the technical groups on the project (very tangentially involved). I know the magnets were always considered a problem (cost/effort), but there weren't other options at the time, as computer vision was too computationally expensive at the time.