Years ago I thought part of the self-driving solution would involve infrastructure: Special lane paints, transmitters along the highway to give vehicles important information, on and on. The obvious problem with anything that relies on infrastructure is all the roads that will NEVER be upgraded. You might be able to connect some important freight routes for self-driving trucks, but you'll never blanket all the places people travel. And so the modern solution requires an advanced AI in the vehicle, to execute the same way, or better than, a human driver. That's really hard, but it looks like it'll be the winning strategy.