passenger seats already have an occupancy sensor that you could probably hook into to make a passenger seat bypass somehow.
don't get me wrong, this would probably be horribly unpopular, but otoh deaths from cars are up ~50% in the last decade, bringing us back to ~1985 in car safety. Something fairly drastic is needed
Amount of driven kilometers are also up massively compared to 1985, meaning that per kilometer we did fine on the safety record.
Stop trying to make cars safer, and reduce the amount of driving you need to do. There is a way to have more liberties and have it improve safety instead of fewer. The liberty to commute, do groceries, and go to the gym by bike is huge life improvement, whilst taking nothing away in terms of car liberties.
don't get me wrong, this would probably be horribly unpopular, but otoh deaths from cars are up ~50% in the last decade, bringing us back to ~1985 in car safety. Something fairly drastic is needed