I don't think technology is the bottleneck here, most cars have on board computers now, sensors for parking, GPS etc.
The bottleneck will be the practical application and governance of it all, which will take forever to sort, especially since each countries legislation will differ.
You know why we won't have autonomous vehicles adopted mainstream any time soon, have a think about how long we've had self checkout service at supermarkets and there are still problems with them that the supermarkets haven't been able to solve practically.
E.g. there is an accepted 10% shrinkage rate on supermarkets having a self checkout lane, that is to say supermarkets accept that by having self checkouts 10% of their goods will be nicked. But that's less costly than not having self checkouts, or less painful than spending time & money trying to solve the problem.
If we can't get self checkouts right it's going to be a long time before we can apply autonomous vehicles!