text: First of all, they are using sensors in them to help navigate them. They are developing special roads, smart roads. There were test tracks built in the 1950's by General motors. They built a concept car that could run on a special track that was embedded with a electrical cable that sent radio signals to a receiver on the front end of the car. Engineers at Berkeley tried something similar. They used magnets with alternating polarity, so the car could read the polarities using the binary code. All of this was proved to be too expensive. They started putting sensors on the cars, postion-estimating sensors, a video camera mounted near the rearview mirror, four automotive radar sensors, a GPS receiver, and an internal motion sensor.