Every single area with a population density over 50/sq mi in the US has "the worst traffic" because nowhere is the public transit and alternative travel (buses,

Every single area with a population density over 50/sq mi in the US has "the worst traffic" because nowhere is the public transit and alternative travel (buses, bikes, walking, etc) viable to displace cars. So everyone, everywhere, is driving cars and consume so much space to do so (between the roads, parking, gas stations, mechanic shops, dealerships, etc) that you cannot build an effective transit system in any major metro area. No city is interested in investing the amount of, well, political capital to make trains ubiquitous and all of them get to suffer endless congestion for it. Its a chicken and egg problem, but modern America was built for the car. To retrofit cities away from the car is resisted on both ends, from the monetary expenditure to do so and how deeply ingrained in the design of everywhere the personal car is. But cars are worse the more you push people into the same urban cores but even if you were able to build for density you can't ever allocate the space for all those damn cars to make it actually beneficial but you also can't get funding for good infrastructure because so few can take advantage of it when they are so low density.