Endorsements are additions to your CDL that authorize driving specific vehicles or carrying specific cargo. Getting the right endorsements expands your job market; getting irrelevant endorsements is wasted time.
Think about what you plan to drive in your first job, then identify which endorsements that job requires. Add others later as your career expands.
| Factor | Safety Endorsements (Air Brakes, Tanker, HazMat) | Vehicle Endorsements (Passenger, School Bus, Doubles/Triples) |
|---|---|---|
| Air Brakes (applies to CDL, not separate endorsement) | Required for vehicles with air brakes (most Class A; many Class B). Tested as a written restriction removal — a 'no air brakes' restriction is placed on your licence if you take the skills test in a vehicle without air brakes. | — |
| Tanker (N) | Required to transport liquid or gas in tanks of 119+ gallons. Tests liquid surge, outage, baffles, high center of gravity. | — |
| Hazardous Materials (H) | Required to transport placardable quantities of hazardous materials. Requires TSA background check in addition to written test. | — |
| Combination Vehicles (no letter — tested in Class A skills) | Covered in the Class A skills test (tractor-trailer coupling). Not a separate written endorsement. | — |
| Doubles/Triples (T) | — | Required to pull double or triple trailers. Written test only — no separate skills test beyond the Class A. |
| Passenger (P) | — | Required for buses designed to carry 16+ passengers. Skills test required in a passenger vehicle. |
| School Bus (S) | — | Required for school buses — includes Passenger endorsement requirements plus additional school bus-specific content. Most stringent endorsement. |
| X Endorsement (Tanker + HazMat combo) | Automatically issued when you hold both N and H endorsements — no separate application. | — |
Which endorsements do most trucking jobs require?
OTR TRUCKING (tractor-trailer): Class A with air brakes (restriction removed). Hazmat and tanker are valued additions that expand job options and sometimes pay. Combination vehicles are covered in the Class A skills test. FUEL/TANKER DRIVING: Class A + Tanker (N) + Hazmat (H). The HazMat background check takes 4-8 weeks — apply early. SCHOOL BUS: Class B or A + School Bus (S) + Passenger (P). Background checks, drug testing, and state-specific criminal history requirements beyond standard CDL. CHARTER/TRANSIT BUS: Class B or A + Passenger (P). SPECIALTY TRANSPORT: Varies — know your employer's requirements before applying.
The HazMat endorsement process — why it takes longer
The HazMat endorsement requires a TSA Security Threat Assessment (STA) — a federal background check that includes fingerprinting and a search of criminal, terrorism, and immigration databases. The process takes 4-8 weeks and costs approximately $86-100. Apply early if you need HazMat for your first job. The STA must be renewed every 5 years when your CDL is renewed. Certain criminal convictions or immigration status issues will result in denial regardless of passing the knowledge test.
The most valuable endorsements for most drivers
Air brakes (removing the restriction) is essentially mandatory — most commercial vehicles have them. If you're doing OTR or regional trucking, adding Hazmat and Tanker over time dramatically expands your job options and negotiating leverage. If you're doing bus driving of any kind, Passenger (and School Bus for school transport) are required. Start with what your first job needs, plan for what you want in 2-3 years.