Section 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.