Japanese cities are crowded. This fact is so well known that The Onion can easily
at it. Earlier this year, the
Japanese Ministry of the Environment
issued a report suggesting that cities in Japan become even more centralized so that "per capita CO2 emissions from automobiles and the passenger transport sector" that have recently increased due to decentralization are reduced, according to
Japan for Sustainability
. By centralizing residential areas, stores and public facilities, people wouldn't have to travel as far as often, the report says. While we think of America as a land where the car is king, the MotE report says that the recent "decentralization has generated a situation in which people cannot lead convenient lives without driving their own cars," again according to JfS.
I lived in Japan for two-plus years, and I found cities to be much more centralized than America or, in some places, Europe. Train stations were hubs of economic activity, with restaurants and shops everywhere you turned once you got out of the train (compare this to your local Amtrak station). Making sure future plans keep people and the things they need - the report also suggests incorporating natural areas like greenways and waterfronts - even closer together seems like a sensible idea to me.
[Source: Japan for Sustainability]