10.1 Alcohol & Drugs

Why alcohol and drugs sit at the centre of crash causation

Chapter 3 grouped crash causes into human, mechanical, and environmental factors. Drink- and drug-impaired driving is a pure human factor that multiplies every other risk: you misread signs (Chapter 7–8), misjudge gaps (Chapter 5–6), fail SIPDE (Chapter 9), and lose the patience defensive driving requires. The Nigerian Highway Code’s motorist section is blunt: do not drink and drive. The FRSC Driver’s Licence CBT treats DUI as a named offence with a code and fine, not as a lifestyle preference.

Quick Answer: DUI (driving under the influence of alcohol or drugs) is an offence; FRSC practice-bank sample fine is ₦5,000. Legal BAC for a private vehicle is 0.05% — 50 mg of alcohol per 100 ml of blood (also stated as 0.5 g per litre). Impairment starts before that limit. Illegal drugs and some medicines that cause drowsiness also count. Effects include slowed reaction, poor judgment, and tunnel vision. Best exam and life answer: never drive after drinking — especially as a learner or newly licensed driver.

Alcohol does not only “make people drunk.” It changes vision, judgment, coordination, and reaction time. That is why a stem that says “I only had two beers and I feel fine” is still a wrong attitude on the CBT: feeling fine is not a legal or physiological measurement.

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DUI as a traffic offence

On FRSC offence schedules used in practice banks:

Memorise the pairing DUI → ₦5,000 for CBT stems. Do not confuse it with SUV seat-belt fine (₦2,000) or SLV speed fine (₦5,000) — same naira figure as DUI for SLV, different code and cause.

What “under the influence” covers

• Alcohol above the legal BAC limit, and in practice any amount that impairs safe control.
• Illegal drugs that alter perception or motor control.
• Legal medicines (prescription or over-the-counter) that warn of drowsiness, dizziness, or slowed reflexes — practice material treats driving under those effects as prohibited and aligned with DUI-style liability.

A medical note does not create a free pass to drive while sedated. If a drug impairs you, you do not drive; you arrange another way home or delay the journey.

Beyond the fine

Practice explanations also note that DUI may involve vehicle impoundment, further evaluation, or court referral depending on circumstances. The exam’s first job is the code, fine, and principle; real-world consequences can be harsher than the sample fine alone. Licence points, insurance problems, and crash civil liability sit outside the CBT score but reinforce why the answer is always refuse to drive impaired.

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Legal BAC for private vehicles

Lock the number in two equivalent forms so either stem wording works:

Exceeding this limit for a private passenger vehicle constitutes driving under the influence. CBT distractors often use foreign limits such as 0.08% (common in some other countries) or 0.02% / 0.10%. For this guide and FRSC practice bank, choose 0.05% (50 mg per 100 ml).

Why the limit is not a “target”

Many candidates treat 0.05% as a budget: “I can drink until just under.” That fails both safety and exam logic for three reasons:

1. Impairment starts earlier. Judgment and reaction degrade at lower concentrations. Tunnel vision and overconfidence can appear while you still believe you are sharp.
2. You cannot self-measure BAC at a party. Body weight, food, sex, fatigue, and drink strength change absorption. Guessing is gambling.
3. Learner and new-driver risk is higher. You are still building automatic vehicle control. Alcohol removes the spare mental capacity SIPDE needs (Search 20–30 seconds ahead, Identify, Predict, Decide, Execute).

Zero-tolerance mindset for learners: plan no alcohol on any day you will drive. If you drink, you do not drive — taxi, ride-hail, designated sober driver, or stay overnight. “I will sleep one hour and then drive” is not reliable clearance.

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How alcohol impairs driving (exam-ready effects)

Link each effect to a road failure:

The Code’s motorist teaching also notes harm to vision and coordination alongside judgment and reaction. On a stem asking “why is drink-driving dangerous?”, prefer answers that name these performance failures, not jokes about “feeling happy.”

Alcohol and other human factors

Alcohol rarely acts alone:

• Phone use (UPD) while impaired is double human failure.
• No seat belt (SUV) while impaired turns a survivable crash into a fatal ejection risk (Section 10.2).
• Speed (SLV / DGD) under impairment destroys remaining safety margin.
• Fatigue after parties or long celebrations — the “morning after” can still leave residual impairment and poor sleep.

Defensive driving assumes others may err; an impaired driver is the error generator. Do not become that person.

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Drugs and medicines

Illegal drugs (stimulants, depressants, hallucinogens, cannabis in impairing use, etc.) can distort time sense, risk assessment, and motor skill. FRSC DUI language covers drugs, not alcohol alone.

Medicines that matter for CBT:

• Labels warning drowsiness, do not operate machinery, may cause dizziness.
• Combinations (medicine + alcohol) that amplify sedation.
• “I have a prescription” does not equal “safe to drive.”

Correct behaviour:

1. Read the label and ask a pharmacist/doctor about driving.
2. If impaired or warned not to drive — do not drive.
3. Never “test yourself” in traffic to see if you feel okay.

Practice-bank style rule: driving with impaired reflexes from such medicines is strictly prohibited and treated under DUI-related thinking.

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Social pressure and Nigerian real-world scenes

CBT scenarios often hide impairment inside a story:

Scenario A — After a naming ceremony. Relatives insist “just drive us home; you only took small stout.” Correct: refuse; arrange another driver or wait until fully sober next day with zero residual plan to drive that night.

Scenario B — Commercial pressure. A taxi or company driver is told to keep working after drinking. Correct: refuse the trip. Public risk is higher; the Highway Code’s commercial motorist duties do not create an alcohol exception.

Scenario C — “I’m a good driver.” Skill does not cancel pharmacology. Expert drivers still need reaction time and judgment; alcohol steals both.

Scenario D — Medicine for malaria or cold. Drowsy antihistamine or strong painkiller before a long Abuja–Lagos-style run. Correct: delay journey or change driver; do not rely on kola or loud music (Chapter 9.3 already rejected those as fatigue cures).

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Decision rules for the CBT

1. DUI code fine sample = ₦5,000 (not ₦2,000, not ₦50,000).
2. Private-car BAC = 0.05% = 50 mg/100 ml = 0.5 g/L.
3. Prefer never drink and drive over “stay just under the limit.”
4. Medicines that impair = do not drive.
5. Effects: slowed reaction, poor judgment, tunnel vision (plus coordination/vision themes).
6. Link impairment to human crash causes and failed SIPDE.

Study checklist for Section 10.1

• Quote BAC in both 0.05% and 50 mg per 100 ml.
• Name DUI and ₦5,000.
• List three body/mind effects without looking.
• Explain why “under the limit” is still unsafe.
• State the medicine rule in one sentence.

Link forward

Section 10.2 covers seat belts, child restraints, and safety kit — the equipment that saves lives when prevention fails. Section 10.3 covers sharing the road with vulnerable users, who die first when an impaired driver loses control. Chapter 11 revisits offence codes (DUI, SUV, CRV, EWT) in the full FRSC fine table context.

BAC memory card (say aloud)

• Percent: zero-point-zero-five percent.
• mg/100 ml: fifty milligrams per one hundred millilitres.
• g/L: zero-point-five grams per litre.
• Action: if you drank, do not drive — do not try to “sit at 0.04.”

DUI versus “I feel fine”

Exam writers love confidence language. The correct counter is physiological: alcohol slows reaction, impairs judgment, and creates tunnel vision long before you admit you are drunk. Combine that with Nigeria’s mixed traffic (okadas, pedestrians, markets) and the safety case for zero alcohol before driving becomes non-negotiable for a responsible Class B candidate.