IMHO...... it will be a long time before self driving vehicles are wide spread and even longer before there are self driving vehicles without steering wheels and a driver take over options
Practical (it's the little things will get you) issues like
- keeping the sensors clean (has been a big issue, will continue to be an issues)
- dealing with bad weather.....like heavy rain, snow, ice, hail you have not seen a lot of testing out side of sunbelt states
- can't always depend on satellite and cell connectivity. I get this just driving from San Jose to Eureka in Cal.
- dependence on clear and consistent pavement markings. this will be cost issue for rural areas....and people always seem to forget about rural areas (i.e places like Montana whey you drive 200 miles or more one way to play highschool sports
Functional issues
IMHO it is not higher speed freeway driving that is the achilles heel for self driving, it will be the slow speed complex everyday situations the will be hard as an example my commute on my bike (or car) during morning school commute hours with with 5 schools, crazy parents running late, kids walking, people walking dogs, kids bicycling, teenagers talking on their phone and otherwise oblivious. Narrow streets where often one car has to wait for another, limited visibility, 1 stop sign, 1 4 way stop sign, 3 traffic lights, 2 crosswalks across 4 lane street. people hanging a right then crossing over 2 lanes in a 100 feet, multple right turns across a bicyclist. I fail to see any current self driving vehicle being able to handle this. and when I talk to people who work in the field....they say...oh take a different route, but the problem is to for parents to get to schools they have to go this way
legal issues:
- the law is not ready for self driving vehicles.
- who gets a ticket if a self driving vehicle has a traffic violation the owner of the vehicle, the occupnat, the company that made the vehicle, the company that made the software and /or hardware?
- which leads to who get's sued if there is an injury