I worked on autonomous Humvee's about 15 years ago and that same technology is whats driving the cars now.
The things that have changed are the sensors and computers are faster and better, the algorithms and NN's are better and deeper and there is so much data now.
We already have autonomous cars and people are diving them and the stuff that they can detect even at fast moving speeds is quite a bit.
They can definitely read signs and getting t\o be under all light, weather conditions.
The higher level decision making processes are simple, but they will get better.
I would say 5-7 years is about the right time frame.