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MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Longer Combination Vehicles
A Glance at Clean Freight Strategies
ENERGY &
FUEL SAVINGS
Rocky Mountain
Doubles
Gallons Saved:
2,166 gallons
Fuel Savings:
13%
Fuel Cost Savings:
$8,233
Turnpike
Doubles & Triples
Gallons Saved:
3,500 gallons
Fuel Savings:
21%
Fuel Cost Savings:
$13,300
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 1 24,000 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 1 991 federal law prevents LCV
expansion into states that did not permit these vehicles before the law's passage. Longer
combination vehicles currently operate in 1 6 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, 1 1 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 because of their length 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.
Continued
U.S. EPA SmartWay | EPA-420-F-16-033 | June 2016 | www.epa.gov/smartway
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MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Longer Combination Vehicles
A Glance at Clean Freight Strategies continued
Savings and Benefits
LCVs are more fuel-efficient, on a ton-mile basis, than typical
combination trucks. For example, a Rocky Mountain Double
consumes 1 3 percent less fuel per ton-mile of freight, compared
to a typical combination truck. This saves over $8,000 in fuel costs
per year. Turnpike Doubles and Triples reduce fuel use per ton-mile
by 21 percent, saving over $13,000 in annual fuel costs.
NEXT STEPS
1 Trucking firms
should consider
use of LCVs on routes
where their use is
allowed and appro-
priate.
2For more informa-
tion on what types
of vehicle configura-
tions are allowed in
each state, contact
your state or federal
department of trans-
portation, or your
state or national
trucking association.
S
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