2010 Pennsylvania Code
Title 75 - VEHICLES
Chapter 45 - Other Required Equipment
4533 - Rear wheel shields.

     § 4533.  Rear wheel shields.
        Every truck with a gross weight exceeding 11,000 pounds,
     trailer and truck tractor (without a semitrailer) driven on a
     highway shall be so constructed or equipped as to bar water or
     other road surface substances thrown from the rear wheels of
     such vehicle or combination at tangents exceeding 22 1/2
     degrees, measured from the road surface, from passing in a
     straight line to the rear of such vehicle or combination.
     (Dec. 9, 2002, P.L.1278, No.152, eff. 60 days)