(a) A motor vehicle when operated in combination with another vehicle is not required to display a lighted lamp, other than a taillamp, if the lamp is obscured because of its location by another vehicle in the combination of vehicles.
(b) Subsection (a) is not an exception for the lighting as provided by this chapter of:
(1) front clearance lamps on the frontmost vehicle in the combination; or
(2) rear lamps on the rearmost vehicle in the combination.