Any motor bus company which wishes to adopt a new schedule of operations or discontinue a service shall, not less than twenty days prior to the effective date of such schedule, give notice thereof to the Department of Transportation and to the chief executive officer of each municipality affected by such schedule. Notice shall also be posted in each bus operated on the route affected by such change and at each ticket agency serving such route and published in a newspaper or newspapers having circulation in the affected area not less than ten days prior to the effective date of such schedule. No such schedule shall be effective until approved by the Department of Transportation.