Alcohol, drugs and illness: the CDL rules
Commercial drivers face a .04 alcohol concentration limit, stricter than for regular drivers (Texas CDL handbook, Section 1). Section 2.22 covers alcohol, drugs and illness for the General Knowledge test.
Key facts
| Part of | the General Knowledge test (80% to pass) | DL-7C p. iv |
|---|---|---|
| Handbook section | §2.22 Alcohol, drugs and illness | DL-7C p. 2-40 |
| Questions in CDL Mile's bank | 8 | CDL Mile, checked against DL-7C |
Key rules
- § 2.22.1p. 2-40
The liver clears alcohol at a fixed rate that nothing speeds up. Coffee and cold showers do not change that rate; only waiting does.
Alcohol and Driving
- § 2.22.2p. 2-42
The rules bar being under the influence of drugs that can make you unsafe, and that can include prescription and cold medicines. A drug from your doctor is allowed if the doctor tells you it won't affect your ability to drive safely.
Other Drugs
Try two questions
General Knowledge · Alcohol, drugs and illness
Which of these servings holds about the same amount of alcohol as a 12-ounce glass of 5% beer?
Tap an answer to see the explanation and the handbook page.
General Knowledge · Alcohol, drugs and illness
According to the handbook, which three things determine your blood alcohol concentration (BAC)?
Tap an answer to see the explanation and the handbook page.
More General Knowledge topics
Questions drivers ask
- What is the alcohol limit for CDL drivers?
- .04% blood alcohol concentration while driving a commercial motor vehicle, stricter than the limit for regular drivers. Driving a CMV at .04% or higher can disqualify you.
- Source: Texas CDL handbook DL-7C, Section 1.3
Sources
Texas Commercial Motor Vehicle Drivers Handbook (DL-7C), revised March 2026, Texas Department of Public Safety. Page references are to its printed page numbers. CDL Mile is independent and not affiliated with Texas DPS.
Updated for the March 2026 Texas CDL handbook (DL-7C). Last checked November 4, 2026.
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