What's the Passing Score on the Kentucky CDL General Knowledge Test?
40 out of 50 — 80% — passes Kentucky's CDL General Knowledge test. The number itself is federal, but the fine print around a missed attempt is where Kentucky's own rules take over.
Where the number comes from, and where it doesn't matter as much
49 CFR Part 383 fixes the CDL general knowledge test at 50 questions and 80% nationwide — no state input, Kentucky included.
What actually differs here: a failed attempt requires only a 24-hour wait before retesting, and there's no cap on how many times you can retry within your CLP's 180-day validity window.
Kentucky's two-tier BAC rule for commercial drivers
Kentucky enforces a graduated response to alcohol in a commercial vehicle: a driver testing between 0.01% and 0.039% BAC is placed out of service for 24 hours, while 0.04% or above brings a full one-year disqualification.
That two-step threshold, rather than a single cutoff, is a detail the exam expects you to know precisely, not just approximately.
The parts of the test that pull scores down
Air brake systems and hours-of-service limits are the two topics most likely to cost points, since both hinge on exact numbers (PSI thresholds, hour caps) rather than driving intuition.
Cargo securement sequencing is another common miss — remembering that the first check happens within 50 miles, then every 150 miles or 3 hours after, is easy to get backwards under pressure.
Read the explanation on every practice question, correct or not — it's what actually closes these gaps, not just re-answering until you get lucky.
Frequently Asked Questions
Can Kentucky require a higher passing score than 80% for the CDL test?
No. 49 CFR Part 383 fixes the CDL general knowledge test at 50 questions and an 80% passing threshold nationwide — Kentucky State Police administers that federal standard rather than setting its own.
How long must I wait to retake the Kentucky CDL knowledge test after failing?
24 hours, and you may retake it as many times as needed within your CLP's 180-day validity period.
What score should I aim for on practice tests?
Aim for 90% or higher consistently before your appointment. That buffer above the 80% minimum accounts for first-attempt nerves and any last-minute rule changes.
Ready to put this into practice?
Start a free Kentucky cdl practice testLast reviewed: 2026-07-22