Environmental Engineering Reference
In-Depth Information
Table
.
Transportation energy consumption by
mode (
)
Light vehicles
%
Heavy-duty road vehicles
%
Aircraft
%
Water transport
%
Pipeline operation
%
Rail transport
%
Motorcycles
%
The total
ning
process adds material to the original oil so the total
volume of output is about
is more than
% because the re
% of the input oil. The
breakdown energy consumption by the elements of the
transportation system in the United States is as shown in
Table
.
This section looks at light vehicles: cars, minivans,
SUVs, and pickup trucks; which use the largest part of
transportation fuels, equivalent to
.
million barrels of oil
per day. The other sectors are important, too, but the
biggest is the light-vehicle sector and that is the focus
here.
Fuel Economy Yesterday, Today, and Tomorrow
Before looking at what can be done to improve ef
ciency
it is interesting to look at what has been happening since
the
rst US CAFE standards went
into effect.
Figure
a
shows the average fuel economy of the US
light-vehicle
.
eet and
Figure
.
b
shows the average
weight and performance of that
eet.
a
shows that mpg changed very little after
the CAFE standards came into full
Figure
.
force in
.
