SmartWay
U.S. Environmental Protection Agency +
Longer Combination Vehicles
A Glance at Clean Freight Strategies
ENERGY & FUEL SAVINGS
Rocky Mountain Doubles
Gallons Saved:
2,165
gallons
Fuel Savings:
13%
Fuel Cost Savings:
$6,305
Turnpike Doubles & Triples
Gallons Saved:
3,500
gallons
Fuel Savings:
21%
Fuel Cost Savings:
$10,185
Increasing the cargo capacity of combination trucks by using longer or multiple trailers
can save fuel and reduce greenhouse gas emissions by up to 35 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 LCVfuel
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. A1991 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.
EPA-420-F-19-025 | August 2019 | SmartWay Transport Partnership | epa.gov/smartway
(continued)

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Longer Combination Vehicles: A Glance at Clean Freight Strategies (continued)
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.
SAVINGS AND BENEFITS
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 $6,300 in fuel costs per year. Turnpike Doubles and
Triples reduce fuel use per ton-mile by 21 percent, saving
over $10,000 in annual fuel costs.
21%
Less fuel

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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.

Please visit the SmartWay website at www.epa.gov/smartway
to access more tech bulletins.
SmartWay
U.S. Environmental Protection Agency^

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