Maps and Data - Average Fuel Consumption at Increasing Road Grades

This chart shows how many gallons (in gasoline gallon equivalents [GGEs]) five different vehicle types consume over 100 miles as the road grade increases from -5% to 5%. As the hybrid electric vehicles (HEVs) and battery electric vehicles (BEVs) go downhill, their consumption drops to zero gallons per hundred miles as a result of their regenerative braking systems. In contrast, the conventional vehicles (CVs) still consume fuel at -5% grade. On an uphill grade, all cars consume more fuel than at a 0% grade. For HEVs and BEVs, fuel consumption increases steadily as road grade increases from -3% to 5%. On the other hand, conventional vehicle consumption increases steadily as the grade changes from downhill to flat, and then drastically increases on uphill grades. Both conventional and hybrid SUVs were more affected by incline than their sedan counterparts, most likely because they are heavier.