What does BAC measure?
Correct answer: The concentration of alcohol in a person's blood.
BAC describes alcohol concentration, not simply a drink count. Its value depends on factors including amount consumed and time.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 79 (physical PDF 93) — What Is Blood Alcohol Concentration?. ↗
Compared with spreading the same amount over several hours, drinking it rapidly generally does what?
Correct answer: Raises alcohol concentration more quickly.
The rate of consumption affects alcohol accumulation. Rapid drinking gives the body less time to process it and is not a safe way to prepare to drive.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 79 (physical PDF 93) — Rate of Alcoholic Consumption. ↗
Two people drink the same amount. Why should they not assume their driving ability is affected equally?
Correct answer: Body size and composition can affect alcohol concentration.
People differ in how alcohol affects them. Matching another person's drink count does not establish that you can drive safely.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 79 (physical PDF 93) — Body Weight and Fat. ↗
Does eating a meal prevent consumed alcohol from reaching the blood?
Correct answer: No; food can slow absorption but does not remove the alcohol.
Food is not a way to eliminate consumed alcohol or guarantee safe driving. The handbook distinguishes slower absorption from removal.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 79 (physical PDF 93) — Amount of Food in the Stomach. ↗
A driver who has been drinking asks for strong coffee before driving. What should you understand?
Correct answer: Coffee does not sober the driver; the body needs time to process alcohol.
Coffee, exercise and cold showers do not speed the removal of alcohol. Arrange a sober ride instead of relying on a quick remedy.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 79 (physical PDF 93) — How Does Alcohol Affect the Body?. ↗
After drinking, someone feels unusually confident about a risky pass. What may this indicate?
Correct answer: Impaired judgment and reduced awareness of danger.
Alcohol can reduce judgment and inhibitions. Confidence can increase while the ability to make safe decisions gets worse.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 80 (physical PDF 94) — Judgment. ↗
Why is alcohol especially dangerous when judging another vehicle's distance at night?
Correct answer: It can impair vision, depth judgment and glare recovery.
Driving depends on accurate visual information. Alcohol can interfere with depth perception and the ability to recover from headlight glare.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 80 (physical PDF 94) — Vision. ↗
How can alcohol affect an emergency braking response?
Correct answer: It can delay the response and reduce coordination.
Recognizing danger and coordinating eyes, hands and feet can be impaired. A slower response leaves less time to avoid a crash.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 80 (physical PDF 94) — Reaction Time and Coordination, continues on printed page 81. ↗
Although someone may initially feel stimulated after drinking, alcohol is classified as what?
Correct answer: A depressant that reduces alertness and control.
The apparent stimulation can come from reduced inhibitions. Alcohol depresses functions needed for alert, controlled driving.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 81 (physical PDF 95) — Alertness and Concentration. ↗
Why is combining alcohol with a sedating medicine particularly dangerous before driving?
Correct answer: The combination can intensify impairment.
Alcohol and other depressants can interact strongly. Do not assume the effects are small or offset each other.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 81 (physical PDF 95) — Every Day Drugs — combining alcohol and medicines. ↗
An over-the-counter cold medicine warns that it may cause drowsiness. What should you do before driving?
Correct answer: Heed the warning and check with a pharmacist if unsure about its effects.
Non-prescription medicines can impair driving. Read the label and get professional advice when the effect on driving is unclear.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 81 (physical PDF 95) — Every Day Drugs — non-prescription medicines. ↗
Does having a valid prescription make it safe to drive while impaired by that medicine?
Correct answer: No; a prescription does not make impaired driving safe or lawful.
The handbook warns that a prescription is not a defense for driving under the influence. Discuss driving effects with the prescriber or pharmacist.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 81 (physical PDF 95) — Every Day Drugs — prescribed sedatives. ↗
You are unsure whether two medicines can be combined safely before driving. Who should you consult?
Correct answer: A doctor or pharmacist.
Medicine interactions require reliable advice. Do not test the combination by driving and seeing how it feels.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 81 (physical PDF 95) — Every Day Drugs — questions about combinations. ↗
A driver has no alcohol in the blood but is impaired by another drug. Does zero BAC rule out a DUI?
Correct answer: No; impairment by other drugs can also lead to a DUI.
A zero alcohol result does not establish that a driver is unimpaired. Tennessee also prohibits driving under the influence of other intoxicating drugs.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 81 (physical PDF 95) — Driving Under the Influence of Drugs or Alcohol. ↗
Is a BAC below .08% proof that a person can drive safely?
Correct answer: No; impairment can occur below that level.
The legal alcohol threshold is not a safe-driving target. Judgment and other driving abilities can be impaired below it.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 81 (physical PDF 95) — Driving Under the Influence — BAC below .08. ↗
Your planned driver has been drinking and you are ready to leave. What is the safer choice?
Correct answer: Arrange a sober driver or another safe ride.
The risk applies to passengers as well as drivers. Choose an unimpaired ride instead of relying on slow driving or a supposed sobering remedy.
Source: Tennessee Comprehensive Driver License Manual (publication notice July 1, 2022; file retrieved September 14, 2026), printed page 82 (physical PDF 96) — Not Just Driving — Riding With Others. ↗
