in vehicle size, weight, and performance. The resulting new LDV fuel economy in 2035 is double today’s value.

• Conservative scenario. The new CAFE target is met 5 years later, in 2025. This improvement rate is then extrapolated out through 2035. Under this scenario, only half of the improvement is used to reduce actual fuel consumption; the remaining half is offset by increases in vehicle size, weight, and performance. The resulting new LDV fuel economy in 2035 is 62 percent above today’s value.

Both scenarios are compared with a “no-change” baseline that corresponds roughly to meeting the EISA target for 2020. The baseline also includes some growth in overall fleet size and miles driven, but no resulting change in fuel consumption. This is because the baseline extrapolates the history of the past 20 years, during which time power train efficiency improvements essentially offset any negative effects on fuel consumption from increasing vehicle performance, size, and weight.

Based on the estimated fuel consumption characteristics of individual vehicle types, shown in Table 4.3, and the fleet efficiency improvements represented in the scenarios, Table 4.6 shows examples of the sales mixes and weight reduction that would be required to meet the CAFE targets and to meet the scenario assumptions beyond 2020. Figure 4.7 shows, for the two scenarios, the corresponding annual gasoline consumption of the U.S. in-use LDV fleet from the present out to 2035. Table 4.7 shows the cumulative fleet-wide fuel savings, as compared with the no-change baseline. These savings can be substantial so long as the proposed fuel-economy standards are met and the rate of improvement is sustained. Table 4.8 gives the corresponding annual fuel savings from the no-change baseline in 2020 and 2035.

Air transportation represents almost half of nonhighway transportation energy use (personal and freight), or about 10 percent of total transportation energy consumption. Fuel expenditures are the largest operating cost for most airlines, thereby driving their investment decisions toward higher energy efficiency. For example, Boeing’s and Airbus’s newest generation of airliners, the Boeing 787 Dreamliner and 747-8, and the Airbus 350XWB, attain a 15–20 percent improvement in fuel efficiency over the aircraft they replace. The new aircraft all employ