Re "big" infrastructure projects .....
.... yes, but maybe smaller less headline grabbing ones?
The A303 (the primary London to SW route) has a single carriageway section up and over Camel Hill near us which is a major bottleneck in the Summer in both directions. Traffic on a Saturday at a standstill or crawling at 15mph, delays of about half an hour. Anyone local knows to avoid it.
There have been proposals to dual it for well over 20 years - Wiki states an improvement scheme was cancelled in 1998; I remember it and I'm sure that one wasn't the first. In a way, it's not a major project, it's about a 3 mile stretch, up, over and down the other side. Now, in 2021 - 6 years after the idea was resurrected again - they are actually going to make a start the improvement scheme this Autumn (so far, they've purloined a couple of fields and built a secure heavy equipment compound at the bottom of the hill); however, it could easily get cancelled again if the Treasury decides the money isn't there due to Covid. But the main problem with it has always been the interminable legal, planning, consultation and examination exercises deemed necessary before the scheme could be approved. This is the killer, and I hate to think how much money has been spent / wasted simply on the bureaucracy before a spade is actually turned.
As for Stonehenge, any scheme there is going to cost billions, be it a tunnel of whatever length or a surface road diverted well away from the Stones, simply because of the topography of the area.
Re "small" improvements ......
We have been complaining about the local roads, which were totally resurfaced about eight years ago. They have been falling to pieces almost since day one and are a patchwork of 'repairs upon repairs'.
You know, I think a lot of this is down to the Local Council mantra of "we have a pot of money we MUST spend by 31st March or we'll lose it AND not get such a big post next fiscal year". So numerous probably unnecessary roadworks are blasted through at speed in February / March - probably the worst months to be doing them - just to keep the beancounters happy.
As for standards of repair, a street in our town was singled out for a new surface a few months ago. Men came, laid tar and chippings, and went. What they singularly failed to do was remove the weeds from the kerb before they started - they just tarmaced, unevenly, up to the weeds. Go figure out how long that's going to last before problems resurface .....