- General Knowledge costs $15; the Commercial Learner's Permit application itself is $30.
- Every knowledge test - General Knowledge or endorsement - requires at least 80% to pass under federal CDL standards.
- Hawaii's county licensing offices administer testing under the Hawaii Department of Transportation's CDL program, referencing the 2005 Testing Model (2017).
- A failed required test means at least a one-week wait before you can retest.
Quick Facts Snapshot
If you only have five minutes before heading to the county licensing office, this is the section to read. The Hawaii CDL Permit Test (HI-CDL) is administered directly by Hawaii's county driver licensing offices under the statewide CDL program overseen by the Hawaii Department of Transportation. There's no separate private certifying body - you're dealing with the same county office that issues your regular driver license, just with an added commercial layer.
For a deeper walkthrough of who's eligible and what documents you'll need, see the full HI-CDL Requirements guide. This cheat sheet assumes you already know the basics and just need the numbers and domain breakdown reinforced.
Fee Breakdown
Money questions trip up more applicants than the actual test content. Here's exactly what you're paying for, with no guessing:
| Item | Cost |
|---|---|
| Commercial Learner's Permit application | $30 |
| General Knowledge test | $15 |
| Each special knowledge test (endorsement) | $5 |
| Aural test (if applicable) | additional $15 |
Notice that endorsement tests are priced separately and cheaply per test ($5 each), so bundling multiple endorsements - say Tanker and Combination - doesn't multiply your General Knowledge fee, only adds the smaller per-test charges. For a complete line-item cost picture including how fees stack for multi-endorsement applicants, check the HI-CDL Certification Cost breakdown.
Eligibility at a Glance
Before you can even sit for a knowledge test, Hawaii requires:
- Minimum age 18 for a Commercial Learner's Permit, 21 for a full CDL
- A valid Hawaii driver license already in hand
- Proof meeting identity, residency, and vision requirements
- Current medical certification on file
- A passing score on all required knowledge tests
These are baseline gates, not test content - but missing one means you can't even schedule a test. The full HI-CDL Requirements guide walks through documentation specifics county by county.
The 8 Exam Domains
This is the heart of the cheat sheet. HI-CDL knowledge testing is organized around eight domains, and which ones apply to you depends on the class of CDL and endorsements you're pursuing.
Domain 1: General Knowledge
Required for every applicant regardless of class. Covers basic vehicle inspection, safe driving practices, and general commercial rules of the road.
- Mandatory first test for all applicants
Domain 2: Air Brake
Required if the vehicle you'll drive uses air brakes - which most commercial trucks and buses do. Skipping this test restricts your permit.
- Affects vehicle-class eligibility if omitted
Domain 3: Passenger
Required for anyone seeking a P endorsement to transport passengers commercially, including bus operators outside the school bus category.
- Pairs with ELDT training for first-time P endorsements
Domain 4: Hazardous Material
Required for the H endorsement. Holders must also maintain TSA eligibility and retest at every renewal cycle - this endorsement doesn't simply carry forward automatically.
- Retesting required at renewal, not just initial issuance
Domain 5: Tanker
Required for the N endorsement, covering the unique handling characteristics of liquid or gas cargo in bulk tanks.
- Often combined with Hazardous Material for fuel-hauling roles
Domain 6: Combination
Covers knowledge specific to combination vehicles - tractor-trailers and similar setups - required for most Class A applicants.
- Central to Class A first-time applicants under ELDT
Domain 7: Double/Triples
Required for the T endorsement if you'll pull multiple trailers. Less common for island-based routes but still tested for interstate-capable drivers.
- Niche endorsement, worth confirming you actually need it before studying
Domain 8: School Bus
Required for the S endorsement, covering student loading/unloading procedures and specific safety rules distinct from general passenger transport.
- Also triggers ELDT for first-time S endorsement seekers
For a domain-by-domain deep dive with more sample question styles and content breakdowns, read the HI-CDL Exam Domains Guide. If you're still deciding how tough this will actually be for your situation, How Hard Is the HI-CDL Exam? puts the domains in context against real difficulty factors.
ELDT and Endorsements
Entry-Level Driver Training (ELDT) isn't optional background reading - it's a federal training requirement layered on top of Hawaii's knowledge tests for specific applicant categories:
- First-time Class A applicants
- First-time Class B applicants
- Class B-to-Class A upgrades
- First-time P (Passenger), S (School Bus), or H (Hazardous Material) endorsements
Key Takeaway
If any of the above applies to you, budget time for ELDT-approved training before you're even eligible to test - this is separate from and precedes the knowledge test itself.
Scoring and Retest Rules
Every knowledge test under the HI-CDL program - General Knowledge or any special endorsement test - requires a minimum score of 80% under federal CDL standards. There's no partial credit system or curve; you either clear 80% or you don't.
If you fail a required test, Hawaii's rule is a mandatory wait of at least one week before you can retest. That means a failed attempt doesn't just cost you the retest fee - it costs you real calendar time, which matters if you're on a hiring timeline. For the exact scoring mechanics and what "passing" really means test by test, see HI-CDL Passing Score: Exactly What You Need to Pass. If you want a broader look at how applicants actually perform, the HI-CDL Pass Rate article covers what's publicly known without guessing at numbers that aren't documented.
Permit and CDL Terms
Once you're certified, how long your credential lasts depends entirely on your age bracket:
| Age Range | Standard CDL Term |
|---|---|
| 21-24 | 4 years |
| 25-71 | 8 years |
| 72 and older | 2 years |
Hazardous Material (H) endorsement holders have an extra layer: they must maintain TSA eligibility continuously and retest the Hazardous Material knowledge test at every renewal - not a one-time hurdle.
One-Week Cram Schedule
If you're close to test day and need a tight review plan rather than a full study program, here's a compressed schedule built around the domains most applicants actually need - General Knowledge plus one or two endorsements. For a full multi-week preparation plan, use the HI-CDL Study Guide; this version is deliberately condensed.
General Knowledge (Domain 1)
- Review vehicle inspection sequence and safe driving rules
- Take practice questions until consistently above 80%
Air Brake (Domain 2)
- Focus on system components and pre-trip checks
- Skip only if your vehicle class truly doesn't require it
Your Specific Endorsement Domain
- Passenger, Hazardous Material, Tanker, Combination, Double/Triples, or School Bus - whichever applies
- Cross-reference ELDT training material if it's your first time seeking that endorsement
Full Review and Scheduling
- Retake mixed practice sets across all tested domains
- Confirm fees and documents before your county office appointment
Notice this schedule deliberately front-loads Domain 1 and Domain 2 because nearly every applicant needs them, then customizes the back half around whichever single endorsement domain actually applies to your goals.
Printable Cheat Sheet Summary
Keep this list handy on test day:
- Permit fee: $30
- General Knowledge test: $15
- Each endorsement test: $5
- Aural test: +$15 if applicable
- Passing score: 80% minimum, every test
- Minimum ages: 18 (permit), 21 (CDL)
- Failed test wait: at least 1 week before retest
- CDL term: 4 / 8 / 2 years by age bracket
- Testing standard referenced: 2005 Testing Model (2017)
Before you decide which domains to prioritize, it's worth understanding where HI-CDL holders actually work - see HI-CDL Jobs for the kinds of positions that hire around specific endorsements, and HI-CDL Salary Guide if compensation is part of your decision-making. If you're still weighing whether pursuing the full credential and its endorsements makes sense for your career path, Is the HI-CDL Certification Worth It? lays out the tradeoffs without inflating numbers.
To practice under realistic conditions before your county appointment, run through timed question sets on our HI-CDL practice test platform - it's built specifically around these eight domains rather than generic trucking trivia. If you haven't locked in a testing date yet, review HI-CDL Exam Dates: Testing Windows, Deadlines & Scheduling so your cram schedule lines up with an actual appointment.
FAQ
No. General Knowledge (Domain 1) is required for everyone, and Air Brake (Domain 2) applies to most vehicle classes, but Domains 3 through 8 are endorsement-specific - you only test on the ones matching the endorsements you actually want.
Each special knowledge test costs $5, so adding a single endorsement after you already hold a CDL is inexpensive compared to the initial permit and General Knowledge fees.
You must wait at least one week before retesting. There's no same-day or next-day retake option under Hawaii's CDL testing rules.
Yes. Class B-to-Class A upgrades are specifically listed as requiring ELDT, the same as first-time Class A or B applicants.
It depends on your age: four years for ages 21-24, eight years for ages 25-71, and two years for age 72 and older. Hazardous Material endorsement holders must also retest and maintain TSA eligibility at each renewal.