The X Endorsement
The X endorsement is the one that confuses people, because there is nothing to study for it specifically. It is not a test. Hold both the hazardous materials (H) and tank vehicle (N) endorsements, and your commercial license shows X in place of listing the two separately.
How to get it
Pass both underlying knowledge tests:
- Hazardous Materials — 30 questions · 80% to pass
- Tank Vehicles — 20 questions · 80% to pass
Because hazmat is one of the two, everything that gates hazmat gates X as well — the ELDT theory requirement and the TSA security threat assessment. Practice both here:
- HazMat practice test — 30 questions
- Tank vehicles practice test — 20 questions
Why it exists
A tanker carrying a hazardous liquid is the combination that most concerns regulators: surge dynamics and a hazardous load in the same vehicle. The X code tells an inspector at a glance that the driver is cleared for both, which is why it replaces the separate codes rather than sitting alongside them.
Renewal
X inherits hazmat's five-year clock. When the hazmat half expires, so does X — see the renewal guide.
More CDL guides
See every CDL knowledge test and guide →
Frequently asked questions
Is there an X endorsement test?
No. There is no separate X knowledge test. You pass the hazmat (H) and tank vehicle (N) tests, and the X code replaces both on your license.
Do I need ELDT for the X endorsement?
Yes, because hazmat is half of it. First-time hazmat applicants need entry-level driver training theory from a registered provider before taking the knowledge test.
