Maximum trailer length allowed on roads. highways and interstates.
The Federal length limits are principally minimums that States must allow for the following vehicles on the NN and reasonable access routes.
Truck Tractor-Semitrailer Combinations
The minimum allowable length limit for the semitrailer in this combination is 14.63 m (48 feet) or the grandfathered limit for a particular State. (See discussion of Grandfathered Semitrailer Lengths on page 3.) A State may not impose an overall vehicle length limit on a truck tractor-semitrailer combination operating on the NN or reasonable access routes, even if the trailer is longer than the minimum length required by Federal law (Figure 2). A State may not impose an overall length limit on a truck tractor pulling a single semitrailer or a limit on the distance between the axles of such a truck tractor.