After driving 2000km over the weekend and then getting stuck in traffic each day since, I've been wondering the same thing. We're a way off trusting our cars enough to sleep while it's moving at high speed, but a car that could handle the crawl into the CBD would free up drivers to check email, read a book or eat breakfast. A lot of that time is waiting and watching for a light change, or moving slowly down a busy road.

Something a bit like cruise control (in the way that it can be quickly overridden) would be a start. Put it in robo-mode and get a warning if you need to take the wheel within the next few seconds.