Or we make the driving test harder. Yes there's a cost, but probably not as great as the cost to the economy as adding journey times to everyone's day.
Personally i think there should be a 3 stage driving test:
1. Before the learner is even allowed to go out on the road, a "CBT" type test on private land at a test centre to prove they can handle the basics of the car. After passing the learner should also be required to log a minimum number of hours (maybe 5) with a qualified driving instructor before being allowed to have practise sessions with a family member supervising.
2. The theory and hazard perception tests
3. A much harder practical test, to include dual carriageway driving (motorway might not be feasible in some parts of the UK) and 60mph country road driving, as well as driving in built up urban areas, etc. All learners should be required to correctly demonstrate both paralell and bay parks.
This would make the road far safer over time, and would also probably reduce the number of kids learning to drive to be just those who actually "need" to be able to drive.