White paper

The evolution of commercial vehicles in China: A retrospective evaluation of fuel consumption standards and recommendations for the future

China’s fuel consumption standards for heavy-duty vehicles (HDVs) have progressed since Stage 1 was first introduced in 2012, and Stage 4 standards are currently in development. However, to date there has been no independent retrospective assessment of the impact of Stage 1 and Stage 2 standards, including whether they spurred any reduction in the fuel consumption of HDVs. This study fills that knowledge gap by analyzing data from 10.5 million trucks and buses in the period 2012 to 2017.

Results show that Stage 1 and Stage 2 standards had only a limited impact on the certified fuel consumption of trucks and buses in China. After Stage 2 was introduced, some HDV segments exhibited only a slight downward trend in fuel consumption, and others even a slight upward trend. Additionally, because a significant portion of the vehicles certified to Stage 2 were already compliant with Stage 3 fuel consumption limits, the actual improvement in certified fuel consumption across the fleet as a result of Stage 3 will likely be less than the tightening of the standards suggests.

Based on this, Stage 4 is an opportunity to set a technology-forcing regulation that would force cost-effective new technologies into the market and improve the competitiveness of Chinese manufacturers in international markets. Moreover, a key finding is that the flexibilities given to manufacturers during the fuel consumption certification have a significant impact on the certified fuel consumption. Including road grade in the certification drive cycle would be beneficial for the real-world representativeness of the certification process and for incentivizing important fuel-saving technologies that thrive on mountainous topographies.