Kei cars are a class of small cars in Japan which have a length limit of 3.4 meters, a width limit of 1.48 meters and height limit of 2 meters. The Kei car class was created (and given tax breaks) as a way to beef up the domestic auto industry after the second world war. According to the kei-cars.com FAQ, mileage of 40-60 MPG, which you would expect from such a tiny car, is common for these vehicles.
Kei cars are popular in Japan today and, as you can see in the video below the fold, the cars are even popular in Canada where Japanoid Imports are allowed to import them after 15 years. They look like toys and are right hand drive but no one seems to mind. The equivalent car to American or Europe would be the micro or city cars.
I though the cars might be powered by a large metal wind-up key or possibly rolling it backwards storing energy in a spring. Turns out they use 660 cc engine or 47 KW electric engines in a variety of drive trains including gas, full electrics and hybrids.
[Source: New York Times, YouTube]