The problem is that even if new roads are reported to map vendors such as TeleAtlas, they take an interminable amount of time to add them.
I have a subscription to software using current TomTom maps. Before that, I had a dedicated TomTom device with a map subscription. Using their Map Insight feature, I reported a new subdivision to TeleAtlas -- which is *owned* by TomTom, remember. I provided them with complete details on the location of the new roads involved, or at least, as complete as is possible with their site.
Two years later, the roads still hadn't been added in my TomTom, at the point where I stopped my maps subscription. Courtesy of the third-party software using TomTom maps (Sygic), I can report that it was about 3.5 years from report until the roads actually got added to the map.
That huge lag -- even when the map vendor and the GPS device maker are essentially one and the same -- is why people have trouble with their GPS. That, and the fact that many of these maps are clearly made from satellite / aerial imagery, rather than from somebody actually pounding pavement -- and so when roads come close enough to each other beneath an obstruction (trees or whatever), the map maker believes the roads to be linked when they're not. (Or in more than one case where I live, their maps report somebody's private driveways between two roads as being a public road.)
And this, coupled with liability, is what's going to do in autonomous cars. 99.999% accurate and safe isn't enough when it comes to an autonomous car, and if you expect the driver to take over when the car gets it wrong, the driver might just as well be driving in the first place. As soon as the first reports come in of people dying because their autonomous cars autonomously crashed, the lawyers will have a field day at the auto makers' expense -- and the auto makers' lawyers know that too.
So they'll allow research and news coverage, because that makes the brand look futuristic and is effectively cheap advertising -- but you will not see these things on public roads in the hands of the public in your lifetime. You may see autonomous commercial vehicles -- especially those which drive predefined routes -- but not autonomous private cars. There's simply too much risk.