(1)    All school buses shall be painted as follows:

      (a)    With the exception of trim, the body, including hood, fenders, cowl and roof shall be painted a uniform color, national school bus glossy yellow, according to national institute of standards and technology specifications;

      (b)    The body trim, if used, shall be black; and

      (c)    The words, “SCHOOL BUS”, in black letters at least 8 inches high shall appear on both the front and rear of the upper body area or on a sign attached thereto.

   (2)   A motor vehicle described in s. 340.01 (56) (b) may, but need not, comply with sub. (1). If the motor vehicle complies with sub. (1), the vehicle shall comply with other regulations relating to school buses prescribed by the department by rule.

   (3)   No person may paint or in any way designate a motor vehicle in the manner described in sub. (1) except as expressly authorized by this section.

   (4)   When a motor vehicle in compliance with sub. (1), s. 347.25 (2), and the rules of the department relating to school bus equipment is no longer operated as a school bus, the registration of the motor vehicle for another purpose may not be permitted until the owner:

      (a)    Physically removes the signs identifying the vehicle as a school bus, the lights required by s. 347.25 (2) and such other equipment as the department may specify by rule; and

      (b)    Repaints the entire vehicle to a color other than national school bus glossy yellow or any color commonly referred to as yellow.