One of the most significant things about speeding time in Japan is the amount of time you spend walking. You use public grasportaion like trains to move one place to the other and the rest is walking. Since I got to Japan 4 days ago, I am averaging over 3 miles of walking everyday.
I think cities like Seattle are trying to be that way but there is one big difference that make public transportation like light-rail will fail. Most cities in Japan are create around railroad stations instead of railroad being build to the locations where they are not design to be. And the population of the cities like Seattle are not big enough to have enough rail cars to be more effective.