WLTP Overview

Japan’s METI and MLIT to Incorporate New Standards into Fuel Efficiency Testing of Passenger Vehicles

In a joint meeting of Japan’s Ministry of Economy, Trade and Industry (METI) and Ministry of Land, Infrastructure and Transportation (MLIT), plans were finalized for incorporating the WLTP (Worldwide Harmonized Light Vehicle Test Procedures for mileage and emissions) into Japan’s laws governing mileage testing for passenger vehicles.

At the meeting, MLIT and METI made progress in deliberations about how to incorporate the WLTP into the nation’s light vehicle fuel economy standards. The existing standards are based on Japan’s “laws for the appropriate use of energy”. The group is taking the necessary steps to ensure that the United Nations-established WLTP fuel economy test guidelines can function alongside Japan’s existing JC08 fuel economy test guidelines.

The fuel efficiency standard values will stay at their present rate this fiscal year but the group has indicated that WLTP and JC08 standards will both be used going forward. However, if certain vehicles in stock do not measure according to both of the fuel efficiency values, they may report only one for now. It was agreed that in practice, the WLTP values tend to be at the same level or lower than the JC08 values. For this reason, the group clarified that the existing JC08 fuel efficiency values will be applied to manufacturing companies without reduction even though each company may choose to apply the WLTP fuel efficiency values to existing vehicles.

Both agencies expect that the incorporation of the WLTP fuel economy standards will encourage automakers to continue to develop improved fuel economy technologies.

The plan is now to amend related laws and regulations in the Spring, based on the decisions at these meetings.