A key component of a CAEP/9 CO2 certification requirement and standard will be the test point(s) used to evaluate the efficiency of aircraft. This paper, presented to the third CO2 TG meeting of the International Civil Aviation Organization's Committee on Aviation Environmental Protection, 20–22 September 2010, surveys the range of test cycles used to evaluate the efficiency of vehicles—including passenger cars and trucks, motorcycles, heavy-duty trucks and buses, and marine vessels—in order to inform ICAO discussion of a CO2 certification procedure. The authors show that efficiency test cycles covering a variety of transport modes typically test vehicles at points representative of operational norms rather than at maximum vehicle capabilities. Testing the efficiency of vehicles near operational norms provides optimal incentives for the adoption of technologies and designs that reduce fuel consumption during real-world operation. In addition, the paper discusses differences between transient and steady-state test cycles and relate those differences to mission-based and point performance metrics currently under discussion.