[aeturnum]

Parking turnover probably scales with population density. One of the reasons parking is more expensive in big cities is to encourage people to move their cars sooner. Smaller cities will have more cars that never move, where larger ones will have fewer.

[giantg2]

If it's about movement, then population density might not be the best factor either. You might need some other way to see the number of humans moving through a given area. Stuff like office buildings have higher populations during office hours, but wouldn't be caught in "population" metrics.