Good thing we get wiser with age. Oh, wait no we don't. We insist on driving while beeing unable to look over the shoulder or having dementia. Knew somebody whose by no deceased dementia afflicted father used google to navigate him home when he forgot where he was. Thats the accidents with a "confused" driver, not from the accident.
Which country is this? In the UK they take your licence off you straight away as soon as there is a dementia diagnosis, I believe.
Most people are losing their facilities years before any formal diagnosis and plenty of people, especially those who don't want to lose their freedom simply won't go to the doctor for a diagnosis. Nobody can force someone to see a doctor.