- Every South Dakota knowledge test - General Knowledge included - requires an 80% score to pass.
- You get only one knowledge test attempt per day, so cramming the night before matters more than most realize.
- The CLP is valid for one year but must be held 14 days minimum before skills testing.
- General Knowledge covers 50 questions; HazMat has 30; Air Brakes has 25; most other endorsements have 20.
Quick-Reference Snapshot
This page is built to be the one-tab-open reference you keep next to your SD-CDL Study Guide 2026: How to Pass on Your First Attempt while you drill practice questions on the main SD-CDL practice test platform. It condenses the numbers, the domain list, and the process steps administered by the South Dakota Department of Public Safety Driver Licensing Program under the 2025 AAMVA CDL testing system into a single scan.
| Test | Question Count | Passing Score |
|---|---|---|
| General Knowledge | 50 | 80% |
| Air Brakes | 25 | 80% |
| HazMat | 30 | 80% |
| Combination Vehicles | 20 | 80% |
| Passenger | 20 | 80% |
| Doubles/Triples | 20 | 80% |
| Tank Vehicle | 20 | 80% |
| School Bus | 20 | 80% |
Fees and Registration Fine Print
The core CDL application fee is $43, and each additional endorsement knowledge test adds $20. If you're scheduling skills testing with an authorized third-party tester, budget $150 plus tax for that portion separately. These numbers matter for planning because they compound quickly if you fail and have to pay again - and remember, you're limited to one knowledge test attempt per day, so failing General Knowledge in the morning means waiting until tomorrow to retry, not the next hour.
- $43 - CDL application fee
- $20 - per endorsement knowledge test
- $150 + tax - authorized third-party skills test
- One attempt per calendar day per knowledge test
- Passed tests and fees remain valid for six months
That six-month validity window is the single most important scheduling fact on this page. If you pass General Knowledge and an endorsement test in January but don't complete skills testing or add remaining endorsements before the window closes, you may need to retest and repay. A full cost breakdown, including how these fees stack for multi-endorsement plans, lives at SD-CDL Certification Cost 2026: Complete Pricing Breakdown.
Eligibility and CLP Timeline
Baseline Eligibility
Before you can even sit for a knowledge test, South Dakota requires:
- Minimum age of 18
- A valid South Dakota Class 1 or Class 2 license already in hand
- Passing identity, residency, and medical requirements
Once you clear those checks and pass your knowledge test(s), your Commercial Learner's Permit (CLP) is issued. Three timing rules govern what happens next:
- The CLP is valid for one year from issuance.
- You must hold the CLP for at least 14 days before you're eligible for skills testing - no same-week shortcuts.
- If your CLP expires before you complete skills testing, you have up to 180 days after expiration to still convert it to a full CDL.
Key Takeaway
Don't schedule your skills test for day 10 of your CLP - it won't be honored. Build your calendar around the 14-day minimum hold, and treat the 180-day post-expiration window as a safety net, not a plan.
One more timing detail that trips people up: any applicable Entry-Level Driver Training (ELDT) must be completed before skills testing or before your first HazMat knowledge test - whichever applies to your endorsement path. Confirm exactly which prerequisites apply to you in SD-CDL Requirements 2026: Eligibility, Prerequisites & How to Qualify.
The 20 Domains, Condensed
South Dakota's knowledge and skills content spans 20 domains. Rather than memorizing them as an unordered list, group them mentally by function - it mirrors how questions are actually written. For the full walkthrough of each area, bookmark SD-CDL Exam Domains 2026: Complete Guide to All 20 Content Areas.
Group A - Rules, Systems, and Inspection (Domains 1-3, 17)
Safe operations regulations, safe vehicle control systems, CMV safety control systems, and vehicle inspections form the regulatory backbone of General Knowledge questions.
- Expect scenario questions about pre-trip checks and system failures, not just definitions
Group B - Core Driving Mechanics (Domains 4-6, 9-10)
Basic control, shifting, backing, speed management, and space management cover the physical handling skills that also show up conceptually on the written test.
- Shifting questions often pair with the Combination Vehicles endorsement content
Group C - Perception and Judgment (Domains 7-8, 11-14, 20)
Visual search, communication, night operation, extreme driving conditions, hazard perceptions, emergency maneuvers, and fatigue and awareness test decision-making under changing conditions.
- These domains reward reasoning through a scenario, not rote recall
Group D - Specialized Vehicle Behavior (Domains 15-16, 19)
Skid control and recovery, relationship of cargo to vehicle control, and mountain driving address how load and terrain change vehicle behavior - frequent territory for Combination Vehicles and Tank Vehicle endorsement questions.
- Cargo securement principles resurface across multiple endorsement tests
Group E - Hazardous Materials (Domain 18)
Hazardous materials is its own dedicated domain and maps directly onto the 30-question HazMat knowledge test - the largest endorsement exam on the list.
- Remember: applicable ELDT must be done before your first HazMat knowledge test attempt
Endorsement Test Breakdown
Not every applicant needs every endorsement, so plan your knowledge tests around the job you actually want. Someone targeting tanker routes doesn't need School Bus content, and vice versa. Matching test choice to job goal is covered in more depth in SD-CDL Jobs and in the broader worth-it analysis at Is the SD-CDL Certification Worth It? Complete ROI Analysis 2026.
- Air Brakes (25 questions): required if your vehicle uses air brake systems - ties heavily to Domain 3, CMV safety control systems.
- HazMat (30 questions): the longest endorsement test; requires ELDT completion before the first attempt.
- Combination Vehicles (20 questions): pulls from shifting, backing, and cargo-relationship domains.
- Passenger (20 questions): emphasizes communication and visual search domains for passenger safety scenarios.
- Doubles/Triples (20 questions): builds on Combination Vehicles knowledge with added space management emphasis.
- Tank Vehicle (20 questions): focuses on cargo-to-vehicle-control relationship under liquid load conditions.
- School Bus (20 questions): layers communication and emergency maneuver domains onto passenger safety rules.
Final-Week Review Schedule
If you've already done the deep study work outlined in the full study guide, use the final week to convert broad domain knowledge into exam-day speed. This is the one place we'll apply general study methodology - but tied directly to South Dakota's specific test structure.
General Knowledge Domains (Groups A & B)
- Drill rules, systems, and core driving mechanics questions against the 80% bar
- Time yourself against the 50-question format
Perception Domains (Group C)
- Focus on hazard perception, night operation, and fatigue-related scenario questions
- Review missed items immediately, not the next day
Your Chosen Endorsements
- Run full-length practice sets matching your actual endorsement question counts (20, 25, or 30)
Weak-Spot Cleanup
- Retest only the domains where you scored under 80% in practice
- Confirm CLP hold-time and ELDT prerequisites are satisfied before booking skills testing
For candidates wondering whether this level of prep is proportionate to the test's actual difficulty, How Hard Is the SD-CDL Exam? Complete Difficulty Guide 2026 breaks down what makes certain domains harder than others.
Mistakes That Cost a Retest Day
Because only one attempt per day is allowed, an avoidable mistake doesn't just cost a fee - it costs an entire day of momentum. The most common ones:
- Scheduling skills testing before the 14-day CLP hold is satisfied. The appointment won't count.
- Skipping ELDT before a HazMat attempt. This can invalidate the attempt entirely.
- Letting the six-month validity window lapse between passing a knowledge test and completing the rest of the process.
- Underestimating shorter tests. A 20-question endorsement test still requires 80% - that's no more than four missed answers.
- Not confirming Class 1 or Class 2 license status before applying, which stalls eligibility from the start.
Practicing under realistic question counts and timing on SD-CDL Exam Prep's practice platform is the fastest way to catch these gaps before they become appointment-day surprises. For a data-informed view of how these mistakes affect outcomes broadly, see SD-CDL Pass Rate 2026: What the Data Shows.
Key Takeaway
Treat the 14-day CLP hold, the six-month test validity, and the 80% threshold as three non-negotiable checkpoints - miss any one and your timeline resets.
FAQ
50 multiple-choice questions, and you need 80% correct to pass.
Only one attempt per day, per test, so plan retakes for the next day if you don't pass.
One year from issuance, with a required 14-day minimum hold before skills testing and up to 180 days after expiration to still convert it to a full CDL.
$43 for the application, plus $20 per endorsement knowledge test, and roughly $150 plus tax for third-party skills testing.
Yes - applicable ELDT must be completed before your first HazMat knowledge test attempt or before skills testing, depending on your path.