That people don't need cars in those two cities.
Um... well, how to put this...
Portland has a population density of ~4900 people per square mile.
Minneapolis ~ 8000 people per square mile
Boston ~ 14,000 people per square mile
NYC ~ 29,000 people per square mile.
My clearly, archetypically
suburban area, just outside of Boston, has a population density of 7,000 people per square mile. There are very few apartment buildings here - it is by far mostly single family homes and duplexes with driveway parking.
If I don't consider my own home "urban", then I'm not going to consider Minneapolis or Portland to be "urban" in this sense, either. While they may be technically the "City of Portland", in terms of population density that looks suburban, to me. And that population density is more relevant for considering travel needs than what people call the place.
That apartment dwellers didn't have cars.
I meant that in urban areas. In Manhattan, only 22% of households own cars.