South Dakota DMV Practice Test 2026

SDCL § 32-23-1 sets the adult DUI per se threshold at 0.08% BAC. Under-21 drivers face a 0.02% limit under § 32-23-21. Commercial vehicle operators face 0.04% under § 32-12A-44. South Dakota's distinctive enhancement threshold is 0.17% BAC: at this level, a mandatory chemical dependency evaluation is required and the administrative license revocation increases from 30 to 120 days (§ 32-23-2.1). A third DUI within 10 years is a Class 6 felony (§ 32-23-4).

Under SDCL § 32-23-10, operating a vehicle in South Dakota constitutes consent to chemical testing. Refusing a test results in license revocation: 1st refusal = 1 year; 2nd refusal within 10 years = 2 years (§ 32-23-11). Under § 32-23-10.1, the refusal is admissible as evidence in any DUI proceeding. Refusal does not prevent prosecution — police may seek a warrant for a blood draw.

South Dakota allows instruction permits at age 14 (SDCL § 32-12-6). The instruction permit hold period is 180 days (reduced to 90 days with a state-approved driver's ed course). During the restricted minor's permit stage, a 10 PM to 6 AM curfew applies (parent/guardian must be in front seat during curfew hours). Passenger restrictions: first 6 months = immediate family only; after 6 months = 1 non-family passenger. All restrictions removed when parent/guardian is in the front seat.

SDCL establishes: interstate maximum 80 mph (§ 32-25-4); interstate minimum 40 mph (§ 32-25-5); urban unposted areas 25 mph (§ 32-25-12); school zone 15 mph when children present (§ 32-25-14); rural divided highways up to 70 mph where authorized by Transportation Commission (§ 32-25-7.1); township roads 55 mph (§ 32-25-9.2).

South Dakota has secondary enforcement for the adult seat belt law — police must have another reason to make a traffic stop before issuing a seat belt citation for adult occupants. The minimum adult fine is $25 with no points assessed. However, operators must ensure passengers between ages 5 and 18 are properly buckled (§ 32-37-1.1). Children under 5 must be secured in an approved child passenger restraint system.

SDCL § 32-26-47.1 prohibits operating a motor vehicle while using a mobile electronic device. Violations are Class 2 misdemeanors — not just traffic infractions — carrying fines up to $500 and potential jail time. South Dakota does not have a separate texting-only prohibition; the statute applies to mobile electronic device use broadly. Emergency calls to 911 are typically exempt.

South Dakota requires headlights from sunset to sunrise and during periods of low visibility such as rain, snow, or fog. Under SDCL § 32-17-7, drivers must dim headlamps to low beam when: (1) the highway is sufficiently lit to reveal a person 200 feet ahead, and (2) whenever meeting or overtaking another vehicle. The 200-foot trigger applies in both scenarios.

Children under 5 must be secured in an approved child passenger restraint system under SDCL § 32-37. Children ages 5 through 18 must wear a properly adjusted seat belt (§ 32-37-1.1). Booster seats are recommended until a child is at least 8 years old or 4'9" (57 inches) tall. Children should remain rear-facing as long as possible, then in a forward-facing harness, then a booster seat, and finally a seat belt.

Completing a state-approved driver's education course in South Dakota reduces the instruction permit hold period from 180 days (6 months) to 90 days (3 months). This is the primary benefit of driver's ed within South Dakota's GDL structure. After completing the reduced hold period, the applicant may apply for a restricted minor's permit.