§ 1213. Obstruction to driver's view or driving mechanism. (a) No
person shall drive a motor vehicle when it is so loaded, or when there
are in the front seat such number of persons as to obstruct the view of
the driver to the front or sides of the vehicle or as to interfere with
the driver's control over the driving mechanism of the vehicle. In no
event shall there be more than three persons in the front seat of any
vehicle, except where such seat has been constructed to accommodate more
than three persons and there is eighteen inches of seating capacity for
each passenger or occupant in said front seat.

(b) No passenger in a vehicle shall ride in such a position as to
interfere with the driver's view ahead or to the sides, or to interfere
with his control over the driving mechanism of the vehicle.