You just don't get it do you.
The transport industry pays £billions in fuel duty, £billions in road tax, and many more £billions in insurance to run their vehicles on the roads in the UK. How much do cyclists pay to use the roads £ZERO. Let's assume a very conservative estimate of 1 million HGVs and your infantile idea would cost the hard pressed transport industry £100,000,000. That's if the work could be done for your wildly optimistic amount.
Hmmmm, I think you may have misunderstood how taxation in this country works.
No one, (or everyone depending on your point of view) "pays to use the road". Roads are paid for out of general taxation - local roads are maintained by Local Authorities and paid for by Council tax/local business rates, and national roads are maintained by the Highways Authority and are paid for by income tax/corporation tax.
Road tax hasn't existed for nearly 100 years in this country. Vehicle owners pay Vehicle Excise Duty (which is a charge based on their toxic emissions) for their vehicles, and the money for that goes into the general taxation pot, it is not ring fenced for spending on roads. In any case, most cyclists also own cars (I do), so pay this anyway.
Not sure what insurance has to do with anything, but I also have insurance cover should I be involved in an accident whilst on my bike (as do many cyclists).
Now stop pedalling (sorry about the pun) this stupid idea and go back to the drawing board.
If you really want to save these morons wouldn't it be better to get them off the road until they learn the highway code and pay for insurance etc.
I agree with you on this though, whilst it's a nice idea, it would be better for society to either educate these idiots, or let them remove themselves from the gene pool.