When ever I see a new place or country allowing a test of these cars this wired article always comes to mind [1]. I think the two main questions will be liability & drivability - 1) when (not if) these cars get into a serious crash, who is to assume liability? Is it Google who created the algorithm? Is it the Audi integrator who fused Google technology into the Audi? Is it the fault of the mapping software that did n…
In order to put an autonomous vehicle on the road, it's going to have to be insured. Insurance companies will have to vet any and all autonomous vehicles anyway, assume direct financial liability for all harms resulting from anything that could go wrong with such a vehicle, and charge whatever premiums they think are approprite to cover those liabilities to the owner of each vehicle.
How they vet autonomous vehicles up to them, and it's probably going to be tricky at first - maybe on a comparable order of trickyness as actually making an autonomous vehicle. But they're going to have to do it if only to get their premiums right. Maybe they'll require certain development practices, like using specific programming languages, or programming conventions within a language, or requiring 3rd party static analysis of all the code (e.g. Coverity), or mandatory reviews of all checkins by at least one other developer than the person who wrote it, or a certain level of automated test coverage, or "passing" a certain percentage of simulated situations.
Whatever the insurance companies do, they're going to have to get some measure of how dangerous these vehicles are.
The better a manufacturer does on the vetting process, the more open they are, the lower the premiums will be to any owners of their cars.
At that point, the insurance companies should be in a position to assume all direct financial liability resulting from an accident - as they are now (discounting your excess) - including negligence, as that's the only incentive we can put on them to ensure they've done their part right. The lawyers will of course ensure that if a vehicle as supplied is not up to the standard that the insurance company confirmed, either in terms of hardware or software, then the insurance company will have a way to take that up with the manufacturer.
Naturally, if you mod your autonomous vehicle in any ways not permitted by your cover, you may void your insurance. At that point the liability falls entirely on you, the owner. But again, that's just as things are now.