Conn. Agencies Regs. § 14-36a-2
The commissioner may issue a driver's license bearing one or more of the following restrictions:
"3" - restricts the licensee who holds an "M" endorsement to the operation of a motorcycle with three wheels;
"B" - restricts the licensee to operation of motor vehicles only when such licensee is using corrective lenses;
"C" - restricts the licensee to operation of motor vehicles only when such motor vehicles are equipped with special controls or equipment;
"D" - restricts the licensee to operation of motor vehicles only when such licensee is employing a prosthetic aid;
"E" - restricts the licensee to operation of motor vehicles only when such motor vehicles are equipped with an automatic transmission;
"F" - restricts the licensee to operation of motor vehicles only when such motor vehicles are equipped with dual external mirrors;
"G" - restricts the licensee to operation of motor vehicles only during periods of daylight;
"K" - restricts the holder of a commercial driver's license to operation of commercial motor vehicles within this state as authorized in 49 CFR 383.153(a)(10), including, but not limited to, all licensees who are eighteen years of age or older but younger than twenty-one years of age;
"L" - restricts the holder of a commercial driver's instruction permit or commercial driver's license to operation of commercial motor vehicles only when such commercial motor vehicles are not equipped with any type of air brakes, in accordance with the requirements of 49 CFR 383.95;
"M" - restricts the holder of a commercial driver's instruction permit or commercial driver's license that contains a "P" endorsement to only those commercial motor vehicles listed in Group B or Group C of 49 CFR 383.91;
"N" - restricts the holder of a commercial driver's instruction permit or commercial driver's license that contains a "P" endorsement to only those commercial motor vehicles listed in Group C of 49 CFR 383.91;
"O" - restricts the holder of a class A license to operation of commercial motor vehicles only when such commercial motor vehicles are not equipped with a fifth-wheel connection;
"P" - restricts the holder of a commercial driver's instruction permit that contains a "P" or "S" endorsement to operation of commercial motor vehicles only when such commercial motor vehicles have no passengers other than a trainer or instructor;
"R" - restricts the licensee to operation of motor vehicles only when such motor vehicles are operated on roadways that are not limited access highways;
"U" - restricts the licensee to operation of motor vehicles only when such licensee is using an operable hearing aid;
"V" - indicates the existence of a medical variance, issued by the Federal Motor Carrier Safety Administration, on the medical certificate of the operator of a commercial motor vehicle, such as an exemption, Skill Performance Evaluation (SPE) certification, or grandfathering provision in accordance with the requirements of 49 CFR 391.49 or 391.64, thereby requiring the licensee to have in his or her possession the original or copy of the medical variance documentation at all times while on duty;
"W" - indicates the licensee has qualified for a medical waiver for the operation of an intrastate commercial motor vehicle based upon medical certification or a Skill Performance Evaluation;
"X" - restricts the holder of a commercial driver's instruction permit that contains an "N" endorsement only to operation of commercial motor vehicles that have a purged tank and no cargo;
"Y" - indicates the motor vehicle operator's license is for driving purposes only and is not for identification or voting purposes; and
"Z" - restricts the holder of a commercial driver's license to operation of commercial motor vehicles only when such commercial motor vehicles are not equipped with any braking system operating fully on the air brake principle.
For purposes of this section, a commercial driver's instruction permit, as described in section 14-44e of the Connecticut General Statutes, is the same as a commercial learner's permit, as defined in 49 CFR 383.5.
Conn. Agencies Regs. § 14-36a-2