CDL · General Knowledge · Nigeria

General Knowledge for the CDL Exam — Nigerian candidates

20% of the CDL test plan. The General Knowledge test (50 multiple-choice questions) is required for every CDL class and covers vehicle systems, road rules, and emergency procedures. Calibrated for Nigerian candidates.

High-stakes exams reward two skills equally: knowledge and test-craft. This page focuses on both for one of the most failure-prone areas. General Knowledge sits at roughly 20% of the Commercial Driver License content distribution — Every CDL applicant takes General Knowledge. Topics include vehicle inspection, basic control, shifting, communicating with other drivers, accident procedures, and driver wellness. In 2024, the published first attempt rate for CDL candidates globally was 65% (FMCSA — applies to Nigerian candidates testing in the U.S.). For Nigerian candidates preparing for CDL, the calibration of study to local context matters: Nigeria has West Africa's largest exam-prep market. WAEC, JAMB, and NECO are the high-stakes national tests; IELTS and PTE are dominant migration credentials.

Common failure modes

These are the patterns that cause most candidates to lose marks on this topic. Recognising them in advance is half the work.

!Misidentifying the controlled-braking vs stab-braking technique
!Confusing the proper following distance rule (1 second per 10 ft of vehicle length, plus 1 second above 40 mph)
!Wrong answer on hazardous-conditions reduced-speed rules
!Confusing the disqualification offences (DUI, reckless, leaving the scene)

Study tips

1Drill following-distance math: 50 ft trailer at 35 mph = 5 seconds; at 50 mph = 6 seconds.
2Memorize disqualification offences and their durations — first DUI = 1 year, second = lifetime.
3Practice stab-braking vs controlled braking with the FMCSA definition.
4Know the wellness requirement: 8 hours sleep, no driving over 11 hours after 10 off.
5In Nigeria, internet stability during CDL computer-based testing varies by centre — booking centres in Lagos, Abuja, or Port Harcourt typically delivers the best test-day experience.

Sample CDL General Knowledge questions

These sample items mirror the format and difficulty of real CDL questions. Practice with thousands more on the free Koydo question bank.

1
You should keep how many seconds of following distance for every 10 feet of vehicle length at speeds below 40 mph?
- A1 secondCorrect
- B2 seconds
- C3 seconds
- D5 seconds
Why this answer?
The CDL rule is 1 second per 10 feet of vehicle length below 40 mph. Above 40 mph, add 1 second. A 60-foot rig at 55 mph thus needs 7 seconds of following distance.

Frequently asked questions

How many questions are on the General Knowledge test?

Most states use a 50-question multiple-choice format. You must answer at least 40 (80%) correctly to pass.

What is the CDL General Knowledge pass rate for Nigerian candidates?

The published first attempt rate for CDL candidates globally in 2024 was 65%, according to FMCSA — applies to Nigerian candidates testing in the U.S.. Pass rates within specific topics like General Knowledge are not separately published, but the topic represents roughly 20% of the exam.

How long should Nigerian candidates study General Knowledge for the CDL?

For most candidates, focused mastery of General Knowledge requires 20–40 hours of deliberate practice — drilling sample questions, reviewing failure modes, and timing yourself against exam conditions. Nigeria has West Africa's largest exam-prep market. WAEC, JAMB, and NECO are the high-stakes national tests; IELTS and PTE are dominant migration credentials. Combine General Knowledge study with full-length mock exams in the final two weeks before your test date.

Practice CDL questions free with Koydo.

Air-brakes, hazmat, pre-trip — every endorsement, every state. Built with a Pass Guarantee.

Start free CDL practice →Practice this topic with AI