Listed below are all documents and RMI.org site pages related to this topic.
This chart shows why less than 0.5% of the energy in a typical modern auto’s fuel actually moves the driver, and only 5–6% moves the auto. An auto's weight is responsible for more than two-thirds of the energy needed to move it. All told, 86% of the fuel energy never reaches the wheels.
Powertrain efficiency from tank to wheels can't exceed 1.0, and is around 0.17 in a typical modern car or 0.35 in a good "full hybrid," but the energy needed to move the car can be reduced severalfold by making it lighter and more slippery.
Each 10% decrease in an auto’s aerodynamic drag can raise its fuel economy by very roughly 3%.
As with lightweight autos, more aerodynamic autos needn’t cost more. A survey of currently available autos shows that lower drag vehicles, as a whole, cost no more than less aerodynamic ones.
Our Revolutionary auto class is based on RMI’s extensive work on the Hypercar. We use a cost model for superefficient battery-electric and fuel cell autos for both cars and light trucks. These vehicles, described in this table, are designed to compete with EIA’s average automobile in price and all driver attributes.
Better design can save up to 45% of U.S. heavy truck fuel, or 1.7 Mbbl/d in 2050, at a weighted-average cost equivalent to $1.00-per-gallon diesel fuel.
Integrating four major aerodynamic features can save about 10% of heavy trucks’ fuel: a nearly sealed tractor-trailer gap, full skirting of the tractor and trailer, a rear drag reducing device, and
optimized cab shape with minimal aerodynamic discontinuities.