Any rationally responsible individual and all civilized traffic regulations respond to the reality that it is a privilege to drive, one earned through certification that the license-holding owner of a vehicle, or a driver of a vehicle has adequate experience and knowledge and capability/dexterity to operate a motor vehicle in urban or other traffic conditions. 

One might assume that those who have been impaired by age-related cognitive and physical problems should have enough common sense left to recognize their responsibility both to themselves and to the driving and ambulatory public to cease driving when health conditions are such as to seriously impact on their ability to safely negotiate roads and traffic.

Yesterday, we parked close to a bank that we frequent, while my husband ducked inside to withdraw money from our account.  The parking space beside us had been vacant, but soon a silver-coloured hatchback slid slowly into place.  My husband returned from his mission just in time to witness, alongside me, an elderly, overweight, badly stooped man slowly emerge from behind the driver's seat of that vehicle.

He emerged slowly and clumsily, found his footing on the ground, and stooped over notably to gain balance and strength from contact with the outer frame of the vehicle, managing to shut the car door.  Then, clinging fiercely to the side of the car he laboriously and cripplingly made his way alongside the car until he was able to reach the trunk.  Where he stopped, stooped over and continuing to use the car as a leverage against falling over, he withdrew himself sufficiently to stand beside the trunk, not hovering precariously over it, to reach into its interior and take possession of a folded-up walker.

The walker withdrawn, he managed to bang shut the car trunk, still balancing himself by a grip on the car and unfolding the walker in a painfully protracted process that seemed to take endless time.  With the walker before him, he shuffled slowly and in the most ungainly manner toward the sidewalk, off the parking lot, lifting himself the one-step height with immense difficulty.

We witnessed this pantomime of dessicated health- and age-related fragility with incredulity that anyone so obviously incapacitated would still be manoeuvring a potentially lethal weapon on public roads.