Unsurprisingly, I should've at least [half] expected] a reply along those *lines (if you'll excuse the *pun). And, to be honest,
it WOULD be difficult to justify the expense involved ... not only in Wales and Scotland, but nationwide.
Frankly, there's NO easy way to curb the amount of traffic on British roads.
But I do believe that if more bulk freight were transported by rail - as it used to be before Beeching's short-sighted (as it turned out) cuts
*in 1963 - then the density of massive haulage vehicles using our motorways would be a lot less, for a start. Hopefully, this in itself, would ultimately lead to fewer accidents involving heavy lorries and trucks ... and limit the damage to the environment caused by burnt fuel pollution from exhaust pipes.
There again, in fairness to the *THEN Minister of Transport, he could hardly have been expected to've been able to foresee the vast increase in the volume of traffic over the ensuing 4/5 decades. I therefore rest my case (which had originally been raised partly in jest!
).