If it is deeply experimental, then it should be conducted in experimental settings, and not on public roads. If regulation is premature, then public tests are also premature. I am surprised I have to explain this. To be on public road the vehicle should pass a minimum benchmark that shows that it can consistently handle at least all the common scenarios..
There is no urgent need for self driving vehicles. It is not like they are going to solve some of the pressing issues that humanity is facing right now. It is just a curiosity, and can may be boost the profits of some corporations. That is about it.
I don't think it is worth or just to risk lives of unsuspecting public towards that end..