This has been discussed a lot.
Post ww2 car oriented cities have a more stable density pattern from Core-edge. Not getting very high but also not getting very low before ending on a dime to open wilderness.
Eastern cities that developed over much longer periods of time and before cars have hyper dense cores but rapidly fade into a ruralish sprawl.
As Ive said before when you take out the preserves and undeveloped land that are just in city limits the density picture changes a lot.
People will look at this list and be shocked at how low Boston scores on density because its very dense in a small area but the metro is very rural where western cities have higher average density across the metro even if the cores are not dense at all.
