[mayniac]

I personally think, during a transition to an SDV majority, human drivers will get worse.

Mainly because good driving is often synonymous with defensive driving. And you don't need to drive defensively if there's a large number of cars on the road which won't unexpectedly change lanes, turn right from the left lane or wildly change speed for no reason. If anything, human drivers might start doing unsafe maneuvers more as they see SDVs around them react quicker and safer to their bad driving. Why bother getting in the correct lane when you can pick the less congested one and rely on SDVs to move out of your way when you barge past?

There's also the issue of people switching from SDV to manually operated vehicles. What if someone uses an autonomous car for commuting on weekdays and gets used to the car acting for them, then uses a normal car on the weekends? They might expect the car to emergency brake for them when a pedestrian steps out into the road, and in the split second it takes them to realise the car will not do that for them they've already traveled too far to stop in time.