Listed below are all documents and RMI.org site pages related to this topic.
Losses due to rolling resistance are higher for heavier vehicles than for autos. In a Class 8 tractor trailer at 65 mph, 13% of fuel is lost to rolling resistance. Wide base single tires save about half of that today, more with next-generation tires.
Short sea shipping could save heavy trucks’ fuel by shifting ton-miles onto ships and waterborne highways that travel up and down our coasts and interior waterways. This would reverse durable trends toward truck freight.
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.
Line haul trucks waste a great deal of fuel idling their engines overnight to power small “hotel loads” that cool, heat, and power personal electronics within truck cabs. Auxiliary power units reduce this use by two-thirds; electrified parking spaces eliminate it.
As with light duty vehicles, lightweighting trucks reduces tractive load. Over 2,800 lb of weight reduction potential is available, lowering the tare weight so more cargo can be carried by fewer trucks.
Parasitic loads are generated by accessories that run the engine or provide power to vehicle systems like cooling fans, alternator, actuators, power steering, air brake compressors, and liquid pumps. Serving these loads more efficiently can reduce heavy trucks’ total fuel use by 3–7% at minimal cost.
Trains can move four times more ton-miles per gallon than trucks, typically at lower cost. Rail intermodal systems, where trains move shipments over medium to long distances and trucks move goods to final destinations, could save upwards of 25% of heavy truck fuel by 2050—perhaps even 60–80%.
Coal currently dominates U.S. rail shipments. If rail intermodal is to expand across the country, trains will need to free up capacity by shipping less coal. This potential is presented in the Renew
cases within Reinventing Fire’s electricity sector.
America's vast transportation system can continue growing and improving all without oil. In 2050 we’d rely on superefficient, lightweight vehicles and planes to move ourselves and our goods. For the remaining 3.1 Mbbl/d of liquid fuel demand not supplied by electric propulsion systems, 2nd and 3rd generation biofuels (or, in trucks, natural gas if desired) could be substituted for oil.