Conn. Gen. Stat. § 14-292: Marking of vehicle operated by student driver.

When any motor vehicle is in use on any highway of this state for the purpose of instructing any person in the operation of a motor vehicle, for compensation or as a part of any school program, the person giving such instruction shall cause to be displayed in a conspicuous place on the front and rear thereof a distinctive marker, not less than twelve inches long nor six inches high, in such form as the Commissioner of Motor Vehicles prescribes, and bearing the inscription “Student Driver”. Failure to display the distinctive markers required by this section shall be an infraction.