It’s sprawl. Building up costs too much via some combination of building taxes, NIMBYs, and construction overhead, so people build out instead. Building out means more and more miles of infrastructure (Roads, water, electric, natural gas, signs, gas stations, etc., etc.) per capita.

Then when the people in the sprawled-out suburbs want to visit the city centers anyway, because that’s where jobs and shopping inevitably are (People live where people live), they have to build massive roads to get in and out.