European urban driving cycle (UDC) comprised of acceleration speed, cruise speed, deceleration speed and multiple start-stop cycles is a standard to quality check the vehicles for its fuel consumption. During the UDC the friction between automotive components can also influence the fuel consumption. Here, we investigate the role of sliding friction during the UDC by reproducing the UDC profile using a ball-on-disk tribometer. Ball and disk made of EN52100 was used in testing the friction behavior of 0W30 and 0W30 with nanodiamonds. Real time friction measurements in 0W30 shows a run-in friction that represents boundary lubrication during the acceleration and deceleration speed whereas during the cruise speed the friction decreased continuously indicating a hydrodynamic lubrication. Addition of nanodiamonds to 0W30 does not influence the friction profile however it reduces the friction. Friction reduced by 20 %, 30 % and 14 % during acceleration, cruise and deceleration, respectively. However, the mean wear scar diameter of the ball remained the same for 0W30 and 0W30 with nanodiamonds. By assuming the fuel consumption due to friction in the car we estimate a fuel saving due to nanodiamonds as 10 L / 100 L (maximum) and 4 L/ 100 L (minimum) during the cruise speed and deceleration, respectively. Overall, we show different lubrication regimes during the UDC and the benefits nanodiamonds in reducing the fuel consumption.