I could see that. In Sweden there were recently a buss accident where a health issue with the driver caused them to black out, killing several people and injuring even more. We put a lot of trust in commercial drivers that are responsible for managing people and several tons of moving vehicle. Pilots employed by commercial airlines generally have an age limit at around 65-68.

What level of impairment is tolerable when the buss driver are driving on the highway at highway speeds?