ยง  211.  General  provisions.  No driver of a motor truck or motor bus
  shall drive such vehicle or be on duty for any period of time in  excess
  of  that  authorized  pursuant  to  regulation  of the commissioner. The
  commissioner is hereby authorized to promulgate  rules  and  regulations
  governing  the  hours  of  service  of drivers of motor trucks and motor
  buses. Such rules and regulations shall be no less protective of  public
  safety  than  the  rules  and  regulations  promulgated  by  the federal
  government with respect to hours of labor of operation of  motor  trucks
  and motor buses, provided, however, that with regard to drivers of motor
  buses   operated   by   a   public  transportation  authority  operating
  exclusively within its jurisdictional area, the rules and regulations of
  the commissioner shall provide that no driver of such motor buses  shall
  drive  more than twelve hours following eight consecutive hours off duty
  and no driver of such motor buses  shall  drive  for  any  period  after
  having  been on duty for fifteen hours following eight consecutive hours
  off duty and every driver of  such  motor  buses  shall  have  at  least
  twenty-four  consecutive  hours  off  duty  in  every  period  of  seven
  consecutive days and in no event shall such a driver be on duty for more
  than seventy-five hours in any period of seven consecutive days.