It matters not how much they improve roads at any given time - traffic will always find the best roads and fill them with vehicles. We've seen it happen time after time over the years. Increasing population and more cars/lorries on the roads automatically increases congestion. People want to drive faster and get to their journey's end quicker, but drivers are going to have to realise and accept that the reverse is the case.
With coastal erosion and flooded areas due to climate change, even what we thought as a finite area for the UK is, in truth, reducing in size.
In making decisions regarding the economic infrastructure of the country, the motorcar cannot be deemed to be anywhere near the top of the list of priorities.
For the immediate future, learning to drive responsibly in the prevailing conditions of congestion is rapidly growing in importance, and failure to face the reality of this factor will ultimately be taken out of our hands and restrictions applied as the powers-that-be see fit.
Make no mistake, the only reason we have not yet been hit hard (I mean really hard), is that the bean-counters haven't to date exhausted all of their less drastic ideas.