As both the number of cars on the road, and the number of older drivers both increase, an additional safeguarding test would seem appropriate.
Personally, I would raise the driving age to twenty-one in an effort to cut down the vast numbers of accidents among younger drivers, and I would instigate a mandatory test every twelve months for every driver over seventy, with a re-test, and then a second failure resulting in the withdrawal of the licence.
We cannot go on pretending that our roads are as they were when I passed my test nearly fifty years ago, and safety constraints should reflect those changes.