I'm not sure why a semi autonomous system of equivalent driving capability would be more dangerous than strictly autonomous vehicles because of "over-trust" unless one assumes that the driver that overtrust the autonomous vehicles and looks away is also inclined to try to override the semiautonomous system whilst doing so. Humans overtrusting a system capable of imperfect Level 5 driving will certainly not be alert to correct all its errors, but on the other hand they should be capable of correcting more than the baseline (especially if the autonomous system is good enough at general driving under most conditions for the human driver to be restricted to "get me off this road train track or flood the system shouldn't have stopped in" and "follow instructions" type edge cases rather than misidentifying objects at high speed type edge cases.)

If there are additional problems caused by human drivers, it's surely that they are inclined to intentionally override the system with dangerous behaviours which is a separate problem entirely, or that their driving ability has atrophied so much from not driving they are unable to handle the boundaries of Level 4...

Overtrust looks like people sleeping or not even bothering to stay in the front seats of the car. https://www.nbcnews.com/news/us-news/california-highway-patr...