CDL Endorsements & Requirements

Pursuant to 49 CFR § 383.93, all commercial drivers who drive certain types of vehicles or haul certain types of cargo must have the appropriate endorsements on their CDL licenses to show that they have the additional specialized knowledge required for these operations. There are five kinds of CDL endorsements that may be required, depending on the vehicle or type of cargo:
 
T - Double and Triple Trailers:  required on the CDL if the driver tows two or three trailers of 10,001 lbs or more GCWR. The driver must pass the doubles/triples written exam to add the “T” endorsement to their CDL.  This endorsement can be added to a Class A CDL.

 
N – Tanker Vehicles:  required on the CDL if the driver hauls liquids or liquefied gases in bulk (1,000 gallons or more). The driver must pass the tanker written exam to add the “N” endorsement to their CDL. This endorsement can be added to a Class A, B, or C CDL.
 
NOTE:  cement mixers do NOT require the tanker endorsement

 
P - Passenger Endorsement:  required on the CDL if the driver wishes to transport 16 or more passengers, including the driver. The driver must pass the passenger written exam and pass a full drive skills test in a passenger vehicle to add the “P” endorsement to their CDL.  This endorsement can be added to a Class A, B, or C CDL.
 
If the driver already possesses a CDL and wants to add the P endorsement, he/she must pass the passenger written exam and purchase an instruction permit with the “P” endorsement prior to drive skills testing in a passenger vehicle.  
 
NOTE:  If the driver takes their drive skills test in a class B passenger vehicle and is issued a CDL license class B with P endorsement, this driver is also qualified to drive other vehicles in the class B category.  However, a driver who completes a drive skills test in a non-passenger class B vehicle CANNOT drive a passenger vehicle/bus.

 
S - School Bus:  required on the CDL if the driver wishes to operate a school bus used to transport students to/from home/school or to/from school-sponsored events. The driver must pass the school bus written exam and pass a full drive skills test in a school bus to add the “S” endorsement.  The driver must either possess a CDL with a “P” endorsement and permit with “S” endorsement or permit with both “P” and “S” endorsements prior to taking the full drive skills test in a school bus.  The “S” endorsement will not stand alone – it requires a “P” endorsement.  This endorsement can be added to a Class A or B CDL.
 
NOTE:  Out-of-state customers surrendering an out-of-state CDL with an “S” endorsement, must take and pass the school bus written and drive skills tests for the “S” endorsement to be added on their Colorado CDL. (There is no reciprocity for out-of-state CDLs with the “S” endorsement.) The customer may drop the “S” endorsement to transfer the out-of-state CDL to a Colorado CDL without the “S” endorsement.

 
H - Hazardous Materials (HAZMAT) or X - Tanker & HAZMAT:  required on the CDL of any driver, regardless of the class of vehicle, who wishes to haul hazardous material or hazardous waste in amounts requiring placarding under DOT regulations. The driver must pass the HAZMAT written exam to add the “H” endorsement to their CDL. Customers holding only a class “R” license who wish to transport hazardous materials in amounts requiring placards must take the CDL drive skills test in a representative vehicle, in addition to the written exam to obtain, at minimum, a class C CDL.  The HAZMAT endorsement can be added to a Class A, Bo, or C CDL.
 
Drivers applying for a new, renewal or out-of-state transfer for an “H” or “X” endorsement must also pass a background check before adding the “H” or “X” endorsement. This includes drivers who dropped their “H” or “X” by request (no grace period), drivers whose license is expired more than one year, or who are reinstating from a restraint action that requires the issuance of a new license and they want the “H” or “X” back on their CDL.
 
 
For additional information, call 303-205-5694 or fill out the web form.