Like from that point alone your asking a large portion of people to trust something less capable than them-selves. We should be aiming for the higher/upper percentiles not the average. Especially, considering how fast a digital control system can operate, average is a horribly low bar.
-Edit-
If throw in the effect that a lot people over estimate their abilities your going to get even fewer people who trust a self driving car that is only as good as average.
It also could be considerably higher depending on the skew of the distribution. Depending how much bad drivers lower the average.