There's more infrastructure under urban roads. Crews come in to fix some utility, shred a section of a lane, patch it poorly with dissimilar materials, and leave.
That's before considering what regular construction crews do. Most of the sidewalks are closed most of the time. They're routinely torn out and never fixed. There are nails and other debris in the roads all the time. When we first moved to our current address, my wife had all four of her tires go flat within the first year. I didn't own a car until two years ago, but both front tires have gotten nails in them already. That's also on top of the city's contracted out private dump truck crushing my rear windshield and smashing the hatch and leaving a business card with a claim number on one of my front wiper blades. That was nice to walk out to.
Then there was the crew across the street stealing all of my power tools when I accidentally left my garage open one day.
I'm not a NIMBY, but experiencing this makes me weary of the Hacker News zeitgeist railing against communities that don't want their neighborhoods turned into constant construction. There are entirely non-evil reasons homeowners might want that because building where people already live is incredibly disruptive.
To me, the trick about allowing more construction in established neighborhoods: Make the noise rules incredibly strict. Tokyo has non-stop construction everywhere. And the noise rules are very strict. It works. In Japan, I assume, for cultural reasons, most construction corps follow the rules. In other places ("The West"), you probably need expensive fines along with manual/automatic on-site inspections.