PERFORMANCE AND COST OF OTHER TYPES OF LIGHT-DUTY VEHICLESMost of the results of OTA’s analyses of mid-size autos apply similarly, on a percentage basis,
to other auto size classes—such as subcompacts—and to light trucks. There are, however, some
interesting differences. For example, the aerodynamics of different vehicle classes are subject to
different constraints. Subcompacts are unlikely to attain as low a drag coefficient as mid-size
vehicles because their short lengths inhibit optimum shapes for minimum drag. Pickup trucks, with
their open rectangular bed and higher ride height have relatively poor drag coefficients, and four-
wheel-drive pickups are even worse, because of their large tires and higher ground clearance. And
compact vans and utility vehicles have short noses, relatively high ground clearance, and box-type
designs that restrict drag coefficients to relatively high values. Although each vehicle type can be
made more aerodynamic, it is unlikely that light-truck drag values will decline quite so much as
automobile drag values can.
Another important difference is market-based—historically, introduction of new technologies
on light-duty trucks has typically lagged by five to seven years behind their introduction in cars.
Although this lag time might change, it is likely that some lag will continue to persist.
Differences in the functions of the different vehicle classes will affect fuel economy potential, as
well. For example, the load-carrying function of many light trucks demands high torque at low
speed, and may demand trailer-towing capability. The latter requirement, in particular, will
constrain the type of performance tradeoffs that might be very attractive for passenger cars using
electric or hybrid-electric powertrains.
Whereas OTA expects the business-as-usual fleet of automobiles to improve in fuel economy
by about 24 percent between 1995 and 2015, the fuel economy of the light truck fleet is expected
to increase a bit less than 20 percent. Prices will scale with size: for example, for hybrids,
subcompact prices will increase by about 80 percent of the mid-size car’s price increment,
compact vans by about 110 percent, and standard pickups by about 140 percent, reflecting the
different power requirements of the various vehicle classes.
LIFECYCLE COST---WILL THEY OFFSET HIGHER PURCHASE PRICES?Although vehicle purchasers may tend to focus on initial purchase price more than on operating
and maintenance (O&M) costs and expected vehicle longevity in their purchase decisions, large
reductions in O&M costs and longer lifespans may offset purchase price advantages in vehicle
purchase decisions. For example, diesel-powered vehicles typically cost more than the same model
with a gasoline engine, and often are less powerful, but are purchased by shoppers who respect
their reputation for longevity, low maintenance, and better fuel economy, or who are swayed by
diesel fuel’s price advantage (in most European nations), or both. Proponents of advanced vehicle
technologies, especially EVs and fuel cell EVs, often cite their claimed sharp advantages in fuel