Increasing vehicle efficiency has been one of the key drivers of the automotive industry worldwide due to new government emission legislations and rising fuel costs. While original equipment manufacturers (OEMs) are responding with innovative hardware designs for new models, lubricant companies are developing additive solutions to reduce frictional losses in the engine thereby increasing fuel economy of both new and existing vehicles.Fuel efficiency of the vehicle can be measured in a variety of driving cycles, including the New European Driving Cycle (NEDC), Japanese JC-08, and FTP-75 (Federal Test Procedure). The type of vehicle used in fuel economy evaluation in the same cycle plays a significant role. Fuel consumption rates for the same vehicle measured in these driving cycles vary due to the differences in the cycles. Thus, to assess the effect of the lubricant on fuel efficiency in various cycles, the fuel consumption is measured relative to a reference oil.In this paper we compare the rate of fuel consumption in the chassis dynamometer test in three driving cycles; NEDC, JC-08, and FTP-75, using the same industry reference oil. We then demonstrate the effect of the formulated lubricant on fuel economy improvement (FEI) in these cycles in the same vehicle. In addition, the comparison of FEI due to the lubricant in different vehicles is done using the same driving cycle. Finally, the effect of the lubricant viscosity and select additives on FEI in various cycles is studied. We show that while the absolute value of fuel economy improvement due to the lubricant depends upon the driving cycle and vehicle type, the ranking of the lubricants in FEI in the same vehicle stays the same in various driving cycles.