Transport Partnership
U.S. Environmental Protection Agency
A Glance at
Clean Freight Strategies:
ombination Vehicles (LCVs)
Increasing the cargo capacity of combination trucks by using longer or multiple trailers can save fuel and reduce
greenhouse gas emissions by up to 34 metric tons per year.
What is the challenge?
The amount of cargo that a typical combination truck
can carry is limited by its trailer capacity. A typical
combination truck consists of a three-axle tractor
pulling a two-axle, 53 foot trailer, with the capacity to
carry approximately 3,800 cubic feet and 45,000
pounds of cargo.
What is the solution?
Longer combination vehicles (LCVs) are combination
trucks with multiple trailers and/or longer trailers than
those used with a standard five-axle combination
truck. Common configurations are:
Rocky Mountain Double: One trailer up to 53
feet long and one trailer up to 28.5 feet long
with a combined weight of up to 120,000
pounds
Turnpike Double: Two trailers, each up to 53
feet long with a combined weight of up to
148,000 pounds
Triple: Three trailers, each up to 28.5 feet
long with a combined weight of up to 132,000
pounds
Eight Axle Twin Trailer: Two trailers, each up
to 33 feet long with a total of eight axles and
a combined weight of up to 124,000 pounds
The extra capacity that LCVs provide enables truck
fleets to haul the same amount of cargo with fewer
trips. LCVs have slightly lower fuel economy, as
measured in miles per gallon, than typical
combination trucks. However, because LCVs carry
more cargo per trip, they require less fuel to haul a
ton of freight one mile. This measure of fuel economy
is called a ton-mile. LCVs generally have much better
ton-mile fuel economy than other combination trucks.
Since only part of a truck's fuel consumption is used
to overcome mass, the percent increase in LCV ton-
miles exceeds the percent increase in LCV fuel
consumption. Increased productivity cuts fuel
consumption and reduces greenhouse gas and air
pollutant emissions. The environmental benefits
could be slightly mitigated if LCV use rises at the
expense of freight train use, since freight trains are
generally more fuel-efficient and have lower
emissions per ton-mile than freight trucks.
Federal and state laws specify truck size and weight
limits. A 1991 federal law prevents LCV expansion
into states that did not permit these vehicles before
the law's passage. Longer combination vehicles
currently operate in 16 states west of the Mississippi
River and on turnpikes in 5 states east of the
Mississippi River. Twenty-nine states do not allow
LCVs. Of the states in which LCVs operate, 11 allow
operation of triples, 8 allow triples with permits, and
8 allow Rocky Mountain Doubles. Three states allow
operation of these LCVs without restrictions.
Additional factors may influence the more
widespread use of LCVs. LCVs have inherent
stability and control limitations becauseoftheirlength
and number of trailers. Therefore, it is important that
only experienced drivers under safe conditions
operate LCVs. Widespread use of LCVs could have
an adverse affect on bridges and other transportation
infrastructure.
The results are in ...
LCVs are more fuel-efficient, on a ton-mile basis,
than typical combination trucks. For example, a
Rocky Mountain Double consumes 13 percent less
fuel per ton-mile of freight, compared to a typical
combination truck. This saves over $3,000 in fuel
costs per year. Turnpike Doubles and Triples reduce
fuel use per ton-mile by 21 percent, saving over
$5,000 in annual fuel costs.
Next steps
Trucking firms should consider use of LCVs on routes
where their use is allowed and appropriate. For more
information on what types of vehicle configurations are
allowed in each state, contact your state or federal
department of transportation, or your state or national
trucking association.
U.S. Environmental Protection Agency A Office of Transp
February 2004, EPA420-F 03 027. ^ For more information,, vtsit: www.cpa.g _
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