75 Pa.C.S. § 4924: Limitations on length of projecting loads.

(a) General rule.--Subject to the provisions of this subchapter limiting the length of vehicles and loads, the load upon any vehicle or the load upon the front vehicle of a combination of vehicles shall not extend more than three feet beyond the foremost part of the vehicle, and the load upon any vehicle operated alone or the load, other than a nondivisible load, upon the rear vehicle of a combination shall not extend more than six feet beyond the rear of the bed or body of such vehicle.

(b) Red flags and lights.--If the load on any vehicle extends more than four feet beyond the rear of the vehicle, a red flag or cloth not less than 12 inches square shall be displayed at the end of the load. During hours of darkness, a red light shall be displayed in the same position in lieu of the flag or cloth.

(c) Compliance with maximum length limitations.--Subsection (a) does not permit loads to exceed the maximum limits set forth in section 4923 (relating to length of vehicles).

(d) Exceptions.--Except for subsection (b), this section does not apply to a motor vehicle specifically designed and being used to:

(1) transport roof trusses; or

(2) transport live trees for transplanting.