What Is The Size Of The Ssandard Semi-Trailer

semi trailer 48 feet

The standard semi-trailer dimensions as set by the U.S. Department of Transportation allow for lengths of 48 to 53 feet. That is the standard length the federal government has set for use on highways across the country.

Commercial motor vehicles, semi-trailers or tractor-hauled trailers also have a maximum width of 102.36 inches, while height is between 13 and 14 feet.

Standard trailer lengths in North America

Note that the federal government hasn’t set any limit on what a state can allow in terms of the height of semi-trailers.

Variations in length and height are common, but width is more standardized. The exception comes in situations like when a trailer truck needs a special rear-view mirror, which may extend the width of the tractor.

The standard dimensions of semi-trailers therefore are:

length: 48 feet

height: 13 feet 6 inches

width: 102 inches

If a truck is hauling a double trailer, then each trailer will be 28 feet long.

In North America, the standard lengths of semi-trailers are 28 ft, 32 ft, 34 ft, 36 ft, 40 ft, 45 ft, 48 ft, and 53 ft. Some states also allow trailer lengths of 57 ft and above, though most have no minimum trailer length for state-wide roads.

For example, Arizona allows a maximum trailer length of 57′ 6″ on its highways and 53 feet on non-Interstate roads.  Most other states allow semi-trailers with a maximum length of 53 feet on Interstate highways and a maximum of 48 feet on non-designated state roads.

Different states have specific laws regulating the height at which commercial vehicles and trailers are allowed to use highways.