The report describes EPA laboratory fuel economy and exhaust emission testing of PetroMoly HP 5W-30 motor oil (hereafter, PetroMoly) at EPA's National Vehicle and Fuel Emissions Laboratory (NVFEL) in Ann Arbor, Michigan. PetroMoly, a product of Worldwide PetroMoly Corporation, is described in their Product Data Sheet as a high performance oil which, when used as a replacement for a conventional motor oil, offers 'Increased fuel economy up to 10%' and 'Reduced toxic emissions up to 60%' in addition to other claimed benefits. EPA's Vehicle Programs and Compliance Division (VPCD) agreed to test PetroMoly on one vehicle because evidence from independent laboratory testing conducted on two vehicles exhibited a statistically significant improvement in fuel economy of four to five percent in city driving and two to three percent in highway driving. The conclusions drawn from EPA evaluation tests are necessarily of limited applicability. An all encompassing evaluation of the effectiveness of a product in achieving performance improvements on the many types of vehicles that are in actual use would require a large sample of test vehicles.