In 1999 the Japanese government adopted fuel efficiency standards based on the Top Runner Program pursuant to the Act concerning the Rational Use of Energy (Energy Conservation Act) and has gradually tightened regulations since then.
Source: Ministry of Economy, Trade and Industry, Japan

Automobiles account for about 90% of CO2 emissions from the transport sector. Automotive fuel efficiency has steadily improved due to active commitment by auto manufacturers, along with tax incentives and other measures. On the other hand, there is a need to discuss new automotive fuel efficiency standards for 2020 because the automotive sector is required to take medium- to long-term measures to combat global warming through further promotion of energy conservation.