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Driver Fitness, Fatigue & Legal Compliance Practice Test

Question 1 of 8

What blood alcohol concentration (BAC) while operating a commercial motor vehicle (CMV) triggers mandatory CDL disqualification under federal regulations?

A 0.02% B 0.04% C 0.08% D 0.10%

✗

Not quite.

Wrong. 0.02% is not the CMV disqualification threshold. Having any detectable alcohol under the standard results in a 24-hour out-of-service order, but does not by itself trigger the 1-year CDL disqualification.

The correct answer is B: 0.04%.

49 CFR 383.51, Table 1 to Section 383.51 (alcohol concentration disqualification)

✓

Correct!

Correct. Table 1 to 49 CFR 383.51 disqualifies a driver for at least one year on a first CMV conviction for operating with a BAC of .04% or higher, far lower than the .08% standard for non-commercial drivers, reflecting the stricter standard applied to commercial operators.

49 CFR 383.51, Table 1 to Section 383.51 (alcohol concentration disqualification)

✗

Not quite.

Wrong. 0.08% is the legal intoxication threshold for a private, non-commercial vehicle in most states. It is not the CMV disqualification trigger, which is set lower at .04%.

The correct answer is B: 0.04%.

49 CFR 383.51, Table 1 to Section 383.51 (alcohol concentration disqualification)

✗

Not quite.

Wrong. 0.10% is not used as a CMV disqualification threshold in the federal CDL rules; the correct, lower threshold of .04% reflects the extra caution required of commercial drivers.

The correct answer is B: 0.04%.

49 CFR 383.51, Table 1 to Section 383.51 (alcohol concentration disqualification)