Lots of people die in car accidents.

Nearly 40,000 people die each year in car accidents. At least 8 of the top 10 causes of accidents would be improved with self-driving cars.

1. Speeding

2. Drunk Driving

3. Speeding

4. Reckless Driving

5. Rain

6. Running Red Lights

7. Night Driving

8. Design Defects

9. Tailgating

10. Wrong-Way Driving/ Improper Turns

Well, no. Has any of the systems been tested in heavy snows on icy roads or on a road without maps?

Aside from figuring out where the edge of the road is, the biggest accident risk that I've seen with driving in heavy snow is speed -- no one wants to drive 15mph for 2 hours through a snowstorm to stay safe, so they drive 30 - 50mph instead.

And I'm not sure how to solve the road visibility issue with self driving cars, but presumably the same heuristics that humans use could be emulated in software (which I suppose is primarily following the car ahead or his tracks or looking for roadside signs that mark the edge of the road).

I doubt anyone would refer to those as silly mistakes either.

My point with the second part is that humans have proven driving in snow storm and places that aren't fully mapped is possible, something that self-driving cars have not.