I don't doubt that US voters won't want to limit speeds to 18mph and fill our roads with speed cameras to enforce it.

I'm guessing that if average commute time in Helsinki was anywhere near what it is in the US they'd probably want to get to their destinations a little faster.

We could probably get away with it if we also redesigned every city and suburb and invested massive amounts of money into public transportation to get something comparable and after all of that I'm sure that many people would probably be happy with what we ended up with, but the disruption of every person's lives in the process would be extremely painful.

We're better off focusing on making sure that new developments are better designed than bulldozing over people's homes and businesses in order to redesign everything we already have.