Back to South Dakota Tests Not South Dakota? Change state

South Dakota Doubles and Triples Test

You'll haul doubles on I-90 across the plains—where wind gusts can flip an empty trailer if you don't know your limits.

Questions

80%

To Pass

Minutes

93 questions · 25 min time limit · 80% to pass

Opens in a practice window — choose your mode inside.

Reviewed by Jack Mahana, CDL Instructor (13+ years)

Last verified: August 2026

All questions sourced from the official South Dakota CDL handbook and FMCSA regulations.

About the South Dakota Doubles and Triples Test

South Dakota lets you pull doubles on most interstates, but you don't see many triples here. That doesn't mean the test is easy. You still need to know coupling procedures, brake timing, and how wind affects a set of trailers. Most of your driving will happen on I-90 or I-29, where crosswinds can shove you into the next lane.

Winter driving matters in South Dakota. Snow and ice change how your rear trailer tracks. You'll learn about interaxle locks and when to use them. The state's commercial vehicle laws follow federal rules, but you also have unique local restrictions near the Black Hills. Know them before you go.

This practice test pulls questions straight from the South Dakota CDL manual. Each question includes an explanation. Take the test multiple times. You need to score 80% or higher—20 questions, 25 minutes, no pauses.

Topics Covered

✓Coupling and uncoupling doubles—critical on South Dakota's long rural ramps where space is tight

✓Brake system control for multiple trailers—key on I-90 downhill grades near the Missouri River

✓Wind stability and speed limits—South Dakota's open plains create sudden crosswind hazards

✓Trailer sway prevention—you face it every time a semi passes you on a two-lane highway

✓Inspecting converter dollies—common failure point in cold South Dakota winters

✓Air brake timing differences between singles and doubles—matters for merging onto I-229 in Sioux Falls

Study Tips

Use the South Dakota CDL manual, not generic guides. The state tests specific coupling procedures you'll need at places like the Flying J in Box Elder. Study the air brake section first—most doubles questions tie back to air brake timing.

Practice with the paper test at the DMV. You can take the written knowledge test at any SD driver exam station—no appointment needed for walk-ins if you arrive before noon. Bring your permit and pay the $12 fee. Answer every question; guessing is better than skipping.

South Dakota Specific Information

South Dakota offers CDL written tests at 19 driver exam stations statewide. No appointment required for the doubles/triples endorsement test—just walk in. Bring your current CDL permit and a valid ID. The fee is $12 per endorsement test. You pay at the counter.

Testing stations in Rapid City, Sioux Falls, and Pierre see the most traffic. Go early in the week if you can. Hours vary by location—check the SD DPS website before you go. You'll get your results instantly. Pass? Your license updates within a week. Fail? You can retry the next day.

Frequently Asked Questions

Do I need a separate endorsement for doubles and triples in South Dakota?

Yes. You need the Doubles/Triples endorsement (X) added to your CDL. You must pass the written test first. No separate road test for this endorsement.

Can I take the South Dakota doubles/triples test online?

No. South Dakota doesn't offer online CDL endorsement tests. You must go to a driver exam station in person. No appointment needed—just walk in.

How many questions are on the South Dakota doubles/triples test?

The official test has 20 questions. You need 16 correct (80%) to pass. You get 25 minutes. It's the same at every station in the state.

What happens if I fail the doubles/triples test in SD?

You can retake it the next business day. No waiting period. Each attempt costs $12. Use our practice test to avoid failing twice.

Does South Dakota allow triples on all highways?

No. Triples are only allowed on specific interstate segments. You won't see them often. The test still covers triples because some local carriers run them from the rail yards near Sioux Falls.

Reviewed by Jack Mahana, CDL Instructor (13+ years)

Last verified: August 2026 · FMCSA-compliant content