Office of Operations Freight Management and Operations

Freight Facts and Figures 2013

Figure 3-11. Permitted Longer Combination Vehicles on the National Highway System: 2011

Longer combination vehicles (LCVs) include truck tractors pulling a long semi-trailer and a short trailer (often called a Rocky Mountain Double), a long semi-trailer and a long trailer (often called a Turnpike Double) or a short semi-trailer and two trailers (called a Triple). Although all states allow conventional combinations consisting of a 28-foot semitrailer and a 28-foot trailer, only 14 states and 6 state turnpike authorities allow LCVs on at least some parts of their road networks. Allowable routes for LCVs have been frozen since 1991.

Figure 3-11

Figure 3-11. U.S. map showing that longer combination vehicles are allowed from Chicago to the Pennsylvania-Ohio border on I-80, the New York State Thruway and the Massachusetts Turnpike, the Florida Turnpike, the Kansas Turnpike, Interstate highways in eastern Colorado, and many routes in Oklahoma, Utah, Nevada, the Dakotas, Montana, Wyoming, Idaho, Oregon, and Washington.

[JPEG 1.67MB, PDF 2.08MB]


Empty triples are allowed on I-80 in Nebraska. NHS mileage as of 2011, prior to MAP-21 system expansion.


U.S. Department of Transportation, Federal Highway Administration, Office of Freight Management and Operations, 2013.


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