Well I have noticed that it seems when a small bridge that handles light traffic volume needs to be replaced, the thing is shut down for years and replaced with a monstrosity that is fit for Interstate traffic. Noticed too that when an simple intersection is "redesigned" the end product is a multi laned affair with all the traffic leaving the intersection being funneled into the same single lane road that existed before with drivers cutting off other drivers to get ahead... Common sense seems like an antiquated concept.
However, I too have a very good idea why this all seems to be true, but I'll keep it to myself also.