Every state's CDL manual carries the same set of federal disqualification rules, and the general knowledge test draws on them. The key idea many applicants miss: several of these offenses count even when you are driving your personal vehicle, not a commercial one.
Major offenses
A first conviction for any of the following costs you your CDL for at least 1 year:
- Driving under the influence of alcohol or a controlled substance
- Driving a CMV with a blood alcohol concentration (BAC) of 0.04% or higher
- Refusing an alcohol test required by implied consent laws
- Leaving the scene of an accident
- Using a vehicle to commit a felony
- Driving a CMV while your CDL is revoked, suspended or canceled, or while you are disqualified
- Causing a fatality through negligent operation of a CMV
If the offense happens while you are driving a CMV placarded for hazardous materials, the minimum rises to 3 years. A second conviction for any of these, in a separate incident, means disqualification for life. Using a vehicle in a felony involving controlled substances is a lifetime disqualification on the first conviction.
One related rule shows up on tests often: if you have any detectable alcohol under 0.04% while driving a CMV, you are put out of service for 24 hours.
Related: What to Expect on the CDL General Knowledge Test
Serious traffic violations
These include speeding 15 mph or more over the posted limit, reckless driving, improper or erratic lane changes, following too closely, a traffic violation connected with a fatal accident, and driving a CMV without a CDL, without it in your possession, or without the proper class or endorsement.
- 2 serious violations within 3 years: at least 60 days.
- 3 or more within 3 years: at least 120 days.
Violations in your personal vehicle count too, if the conviction results in your driving privileges being revoked, canceled or suspended.
Railroad-highway grade crossing violations
Failing to slow down and check for a train, failing to stop when required, not leaving enough room to clear the tracks, ignoring a signal or crossing guard, or getting stuck because of low undercarriage clearance:
- First violation: at least 60 days.
- Second within 3 years: at least 120 days.
- Third within 3 years: at least 1 year.
Out-of-service order violations
Driving after being placed out of service is treated seriously:
- First violation: at least 90 days (at least 180 days if hauling hazmat or 16 or more passengers, including the driver).
- Second within 10 years: at least 1 year (3 years with hazmat or 16+ passengers).
- Third or more within 10 years: at least 3 years.
How to remember it
A useful pattern: major offenses are measured in years, serious violations in days, and a repeat of a major offense is for life. If a test question mentions hazmat, look for the longer period. Try our CDL practice questions.