Japanese cars are known for being compact cars. The reasons for the smaller size are the narrow roads, smaller physical frame, and the economics of owning an affordable car. Over time, these Japanese cars have crossed to other countries and become a popular choice, for similar reasons.
Over time though, the cities in Japan have become more crowded and difficult to drive around in. With an effective mass transportation system, many opt not to own a car or buy a smaller compact. Japanese people who are very family-oriented use the cars to travel outside the cities where mass transportation is not as well organized.
Before the earthquake and tsunami in Japan, compact cars were increasingly in demand. Aside from Japan, other countries saw the compact car as the perfect solution to the growing cost of fuel and high prices of manufacturing cars. It was one way to sell cars faster and for consumers to be able to afford a brand new car ever so often.
After the disaster, there was a slowdown in production in Japan but an increase in production in other countries trying to take up the slack. Whether to the credit of Japanese car makers or not, people still looked to Japanese cars as the benchmark. Many opted to buy used Japanese cars instead of buying a unfamiliar brand. Prevalent still was the orientation that it would be more practical to use your money to buy something you know you can rely on than take chances and end up with a lemon or inferior brand.
In addition, Japanese drivers are known to be cautious drivers and excellent in upkeep. Thus, as soon as Japanese car companies began to find solutions to their post earthquake/tsunami problems, production of compact cars began to restart.
Related to this is the current global crisis of economies under stress. Unemployment was rising and income was dwindling. The answer to the gripping problem was to start a business or be part of a business venture. Some of the businesses that began to show were fleet services like taxi service, or in the buy and sell car business. This is another reason for why the demand for compact cars began to increase. No doubt this trend will continue as the new cars become more fuel efficient while staying affordable.