§ 142. School  bus. Every  motor  vehicle  owned  by  a  public  or  governmental  agency  or private school and operated for the  transportation of pupils, children of pupils, teachers and other persons  acting in a supervisory capacity, to or from school or school activities  or  privately owned and operated for compensation for the transportation  of pupils, children of pupils, teachers and other persons  acting  in  a  supervisory capacity to or from school or school activities.