Friction modifiers or friction reducers have been established for several years. Originally the application was for gear oils, transmission fluids, slideway lubricants (for elimination of stick-slip from slideways) and multipurpose tractor fluids for wet brakes, etc., in fact anywhere where controlled movement is required. Following the Gulf crisis in 1978, fuel economy for all vehicles became an international issue. This led to the introduction of friction modifiers into automotive crankcase lubricants, the objective being to improve fuel efficiency via the crankcase lubricant. In the US, additional pressure was imposed on the oil and additive companies by the introduction of corporate average fuel economy (CAFE) regulations. (CAFE certification is a US Government requirement for engine manufacturers.) Reproducible measurement of fuel saving due to the lubricant was set as a target for the industry. This led to the development of the Sequence VI test for fuel consumption. To satisfy the Sequence VI, the lubricant must show decreased fuel consumption relative to a reference lubricant in a General Motors 3.8 litre stationary bed engine. From September 1995 this test has been replaced by the Sequence VIA, which uses a Ford 4.6 litre engine in a similar manner although a different test sequence. For oils claiming Fuel Efficiency under the ILSAC GF-2 designation, the degree of improvement relative to a specified test lubricant is dependent on the starting viscosity of the lubricant. The engine test is relatively insensitive to friction modifiers and more sensitive to the lubricant viscosity. In Europe the Mercedes M 111 engine is used in a similar manner, although it is expected to be more susceptible to friction modifiers.