technological and econometric models to estimate technological improvements by size class and
performance and size class mix choices by consumers.
Under OTA’s assumptions about future gasoline prices and economic growth--prices increasing
to $1.55/gallon by 2015, from $1.15/gallon in 1994, in constant (1994) dollars^9 (growth rate of
about 1.5 percent per year), personal income growing at 0.9 percent per year--the model projects
a fuel economy of 34.0 mpg for domestic cars and 24.9 mpg for domestic light trucks in
2015, which is a 24 percent increase relative to 1995. These increases are expected to be
attained even in the absence of new fuel economy standards or other measures aimed at increasing
automotive efficiency. Details on the four vehicle classes are provided below.
In general, a number of new technologies are expected to be gradually introduced into the fleet
during the 1995 to 2015 period, simply because the technologies are relatively cost-effective, and
for competitive reasons. For example, high-strength, low-alloy steel optimized structures should
be used widely by 2005, while plastic parts (mostly non-load bearing) will be widespread by 2015.
Drag reduction to CD levels of 0.28 will be commonplace for cars by 2015 and a significant
fraction will be at CD levels of 0.25. Four-valve engines will almost completely replace two-valve
engines in cars by 2005, and in light trucks by 2015. Variable valve timing of both the “two stage”
type and fully variable type will be widespread. Major technological changes to the four classes
considered for 2005 and 2015 are summarized in table 4-1.
The general trends in technology adoption are quite similar across classes, although the
compact van and pickup truck classes lag the two-car classes technologically. This is based on the
historical fact that introduction of new technologies into the light-duty truck (LDT) fleet has
typically lagged by five to seven years behind their introduction in Cars.l0 Table 4-2 has the fuel
economy forecast for each class along with vehicle weight and horsepower. Fuel economy of the
cars is expected to increase by about 24 percent between 1995 and 2015, while the light-truck
fuel economy increase is a little less than 20 percent.
These overall fuel economy increases hide the fact that technologies contribute about 10
percent additional fuel economy that is lost to changes in other vehicle attributes. Safety
standards and customers’ choices of safety equipment such as antilock brakes and traction control
will add 60 to 80 lbs per vehicle, affecting subcompacts disproportionately in weight. These
safety improvements are expected to cause a 1.5 to 2 percent decrease in fuel economy. The
forecast also assumes that federal Tier II standards will essentially equal low emission vehicle
(LEV) standards and be in place by 2005. Unless there are significant improvements in
technology, LEV standards will cause about a 2 percent fuel economy penalty. Consumer
demand for size, luxury, and performance will increase both weight and horsepower of the
vehicle. In the OTA baseline, increases to body rigidity and size within each market class will
contribute to a 6 percent increase in weight (over what it would be otherwise), and a 4
percent decrease in fuel economy. Finally, the model predicts that, if fuel prices rise as
projected, performance increases will likely be restrained and lead to only a small 2 percent
reduction in fuel economy.
(^9) Based on U.S. Department of Energy, Energy Information Administration, Annual Energy Outlook, 1994 (Washington, DC: February 1994),
baseline case. 10
Energy and Environmental Analysis, Inc.,“The Fuel Economy Model: Documentation Report to EIA,” October 1993.