alt Hacker NewsThe size of the United States has not increased since 1970, but the number of people has. So yes, no shit, (US pop / US land area) has gone up. But the question is, "is the average neighborhood more dense than it was in 1970", and that's not a question you can answer from that number, because obviously cities & towns have spread since then.
If you want an intellectually honest comparison, take a look at the District of Columbia, which is basically 100% city and has been for many decades. It's gone down since 1970.
No one asked that question except for you.
The other commenter and I were talking about cars.
Car ownership rates increased slightly, number of households nearly doubled, and average population density went up in every state except DC. There are more cars. Cars do not stay in one place, especially in the case of suburbanization.
Also, I'm not sure why/how the DC piece is intellectually honest. The Washington Metropolitan Statistical area has more than doubled in population since 1970[1]. Do you think all of the people who moved to PG County stay out of DC? That must be why the beltway is so easy to maneuver!
1: https://en.wikipedia.org/wiki/Washington_metropolitan_area