Most tractor trailer trucks have a height between 13 1/2 to 14 feet. There are special allowances and restrictions in some states for low clearances on certain roads.
Unlike the length and width of the truck, there is no federal requirement for the height of a tractor trailer. States can make their own regulations for this aspect. In terms of other dimensions, the maximum width is 8 1/2 feet. The minimum trailer length limit is set at 48 feet. There are certain exceptions to this regulation, including those tractor trailers that have been determined as "grandfathered" in their respective states.