It’s a simple question with no doubt a very complicated answer... We have many thousands of miles worth of motorways/dual carriageways etc in this country, with many of the concrete bridges/viaducts etc having been built in the past six or so decades, and we were probably in a heyday of road building from the late 1960s up to the early 1990s I guess? I’ve been wondering recently though how long some of these structures can reasonably last? Obviously there was the terrible bridge collapse in Genoa, Italy last year which shows how a flawed design and poor maintenance can cause a catastrophic failure: https://en.m.wikipedia.org/wiki/Ponte_Morandi That was an exceptional case obviously. However are we edging towards a time in perhaps thirty or forty years where a huge amount of the road networks infrastructure will need replacing as life expired? I’m thinking of things like the elevated section of the M4 coming into London for instance. I mean can you imagine the cost and disruption of replacing something like that? I’m hoping some people on here might be knowledgeable on such things..?