There is a moral hazard with ADAS + human drivers:
> Once drivers move from the novelty phase to the post-novelty operational phase, behavioral adaptation may begin to occur and overreliance and over-trust in the automation features potentially develop, including a greater willingness to look away from the forward road (as shown in the VCC data set). [1]
I'm not sure if this is more dangerous than strictly human-operated vehicles, but I would wager that it is more dangerous than strictly autonomous vehicles.
1. https://aaafoundation.org/research/understanding-the-impact-...
There was research some years ago in Sweden that cars with 4WD get into accidents 20% - 30% more often than cars with 2WD. And cars with 4WD averaged 10% higher speed at the moment of the crash.
The cause was found to be drivers with 2WD losing a little traction early in their drove and subsequently slowing down, while drivers with 4WD just kept driving like normal until they were suddenly off the road.
Another statistic is that intoxicated or otherwise impaired drivers cause more than half of all fatalities. So making a solution with machine learning and cameras that could retrofit into any existing car and just deny starting the car for such drivers, and having insurance companies cut premiums for having such gadgets installed, would be much more effective than any form of self driving or similar.
https://mb.cision.com/wpyfs/00/00/00/00/00/3E/5A/A2/wkr0011....
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...