They've actually been around since the 1950s. Both the auto industry and electronics industry have tried a lot over the years to develop some kind of self driving car. Until the 1990s most of the effort has gone into utilizing some sort of wire or sensor embedded in the road to help guide the car, along with sensors onboard to detect obstacles. The earliest attempts were a joint project with General Motors, RCA, and the Nebraska Highway Department started in 1957. They later built a test track in NJ with working prototypes.
Newer efforts have tried to utilize GPS, visual detection technology, and powerful computers with sophisticated algorithms to drive the cars. However, the problems are still the same....they can make it work on a vacant roadway, but the trouble is trying to figure out what the other cars are going to do.
Here's a couple of articles from 1950s magazines that discuss in some detail the early systems.
https://books.google.com/books?id=xiUDAAAAMBAJ&lpg=PA76&dq=gm%20rca%20automatic%20highway&pg=PA75#v=onepage&q=gm%20rca%20automatic%20highway&f=false (Interesting in this one that the person at Ford predicted it would take a century of development for self driving cars to become a reality. That was 60 years ago.)