CDE Alcohol, Drugs & Impaired Driving

Question 1

In all U.S. states, what is the legal blood alcohol concentration (BAC) limit for drivers aged 21 and older?

Accepted Answer

0.08%

Answer

The legal BAC limit for drivers 21 and older is 0.08% in every U.S. state, established through federal legislation in 2000.

Question 2

Under zero tolerance laws, what is the BAC limit for drivers under age 21 in most U.S. states?

Accepted Answer

0.01% or 0.02%

Answer

Zero tolerance laws set the BAC limit for underage drivers at 0.01% or 0.02%, making it effectively illegal to drive after consuming any alcohol.

Question 3

Which part of the brain is most immediately affected by alcohol, impairing a driver's judgment and decision-making?

Accepted Answer

Frontal lobe

Answer

Alcohol first impairs the frontal lobe, which controls judgment, decision-making, and impulse control — critical functions for safe driving.

Question 4

At a BAC of 0.05%, which driving-related skills are most noticeably affected?

Accepted Answer

Reduced coordination, reduced ability to track moving objects, and difficulty steering

Answer

At 0.05% BAC, drivers experience reduced coordination, reduced ability to track moving objects, and difficulty steering, according to NHTSA research.

Question 5

Which of the following is the ONLY reliable way to sober up after drinking alcohol?

Accepted Answer

Time

Answer

Only time allows the liver to metabolize alcohol; coffee, food, and cold showers do not reduce BAC or improve driving ability.

CDE - Comprehensive Driver’s Education Practice Test