lolder Report post Posted June 3, 2014 At highway speeds where the ICE is running all the time, the hybrid advantage tends to disappear. The only remaining advantage is the lower Brake Specific Fuel Consumption ( BSFC ) of the Atkinson ICE and whatever additional drag reduction ( Cd ) is accomplished. You can pretty much predict the economy of a car just by looking at it's weight, BSFC of the ICE, ICE horsepower and Cd. Tires and any transmission losses have a small effect also. 2 GrySql and hybridbear reacted to this Quote Share this post Link to post Share on other sites