I find it a bit bothersome when you start to compare SF to Tokyo. The fact that its subway only serves a bit more than 20% of Tokyo's rail traffic, yet at the same time is world top at daily passenger-kms, shows just how massive Tokyo's public transport network is. Earthquake safety have nothing to do with this, it's simply the ability and will to invest in public transport on a massive scale that's proportionate to population growth. I mean just look at table [1]. Japanese do a factor of 25 times the rail passenger kms per person compared to Americans. And I don't think Americans have a much shorter commute. Another way to put it, Switzerland, in total, with just 8M inhabitants, does 1.8x the passenger rail traffic as the whole US [2]. Just think about that for a moment. It doesn't matter whether you put it under ground, above ground or through somebody's swimming pool - any rail is progress in the US.

Edit: Another fun list: The world's 50 busiest train stations. Guess how many are Japanese [3].

[1] https://en.wikipedia.org/wiki/Rail_usage_statistics_by_count...

[2] https://en.wikipedia.org/wiki/Rail_usage_statistics_by_count...

[3] http://en.rocketnews24.com/2013/01/30/the-51-busiest-train-s...