If you can afford it.

While cars in Japan are typically smaller than those in the US, there are certainly exceptions. This hummer H3 for example which, as a side note, gets 14 mpg which is actually not exceptionally bad considering it's size. In any case I wouldn't be surprised if it costs the owner more to park this beast than it does to fuel it. Gas costs $5.75 per gallon in Japan which is high, but not prohibitively high. While gas prices undoubtedly factor into purchasing decisions in Japan, smaller gars are also generally cheaper to begin with. The compact "boxy" cars typically associated with Japan often sell for $8000 or less. Since most cars in Japan are small, there is also less of a fear of crashing into larger cars. There seems to be a kind of arms race going on in the US when it comes to car size that doesn't seem to be an issue in Japan. Finally, navigating Japanese side streets in a larger car would be extremely difficult. While Semi trucks in the US try to avoid residential streets, large trucks in Japan are quite literally wider than some streets.