How about a novel non-infrastructure proposition which would provided substantial benefits in each respect at little or no cost to the taxpayer?
The answer is to make all motorists take a driving test every 10 years. It could be run on a self-financing basis with a "three strikes" and you return to learner status format.
Given that the vast majority of accidents are caused by bad driving rather than mechanical defects, i, we are inconsistent in not having a unified approach to road safety with older cars being checked every year but drivers tested only once in a lifetime.
Between the ages of 17 and 70, peoples driving abilities can change dramatically (as well as their eyesight) but no-one ever checks regularly to see whether they are still fit to drive.
Whilst appreciating that this move would not be universally popular, it's hard to argue against it in principle. I would go further and propose that the re-take period be reduced to every 5 years until the driver reaches the age of 30.
PHIL METHERELL (M), email@example.com