Why did an autonomous car with a map that tells it there's a crosswalk around a blind corner round the blind corner so fast it couldn't stop if there was unexpected debris on the road?
What a stupid scenario, autonomous cars have infinite patience, and when the people inside them can watch netflix all the way to work they won't care much about a few extra seconds either.
The obvious solution is to program the car to never take any blind corner, mapped crosswalk or not, so fast it can't stop on a dime. These things are going to have to work in winter in Canada. Low traction is a regular problem they'll have to solve. That'll mean every auto that takes this corner will do it very slowly, but that's fine because it can report back to the citywide network that this corner is unsafe, meaning all other autos will avoid it if they can (so no congestion), and as a plus it can be registered for modification with the local council. Maybe a networkable sensor can be erected, allowing the cars to see around the corner.
Taking corners faster than you can stop if there's a problem is a very human thing to do. One of the key benefits of autos is they won't do that.