Older drivers may well have physical problems that limit their ability, at 66 I know my reactions what they were 40 years ago! But the big problem is younger drivers, not necessarily just through their test, who drive like they own the road and disdain signalling, road positioning or any allowance for other users. I'm all in favour of retests for everyone, and making medical staff, including opticians responsible for reporting drivers who may not be fit enough to drive. That first, before a blind 'retest at 70 policy', seems more likely to make our roads safer.