Vision, fatigue, distraction and aggressive driving

Key points

1. For an unrestricted license you need 20/40 or better with both eyes and no worse than 20/50 in either eye.

   Source: Handbook p. 18

   “To qualify for a driver license without restrictions, an applicant must score 20/40 or better with both eyes, but no worse than 20/50 in either eye.”
   South Dakota Driver License Manual, Handbook p. 18

2. Most people need 7 to 9 hours of sleep to stay alert.

   Source: Handbook p. 18

   “Get adequate sleep - most people need 7 to 9 hours to maintain proper alertness during the day.”
   South Dakota Driver License Manual, Handbook p. 18

3. Plan to stop about every 100 miles or 2 hours.

   Source: Handbook p. 18

   “Plan to stop about every 100 miles or 2 hours.”
   South Dakota Driver License Manual, Handbook p. 18

4. If you feel tired, pull off and take a 15 to 20 minute nap or find a place to sleep.

   Source: Handbook p. 19

   “If you start feeling tired, stop driving and pull off at the next exit or rest area to take a 15 to 20-minute nap or find a place to sleep for the night.”
   South Dakota Driver License Manual, Handbook p. 19

5. Texting, reading texts and social networking while driving are prohibited by state law.

   Source: Handbook p. 19

   “Texting, reading texts, and social networking is prohibited by state law.”
   South Dakota Driver License Manual, Handbook p. 19

6. Aggressive driving includes speeding, following too closely, unsafe lane changes and ignoring traffic controls.

   Source: Handbook p. 19

   “Some behaviors typically associated with aggressive driving include speeding, following too closely, unsafe lane changes, improperly signaling, and failing to obey traffic control devices”
   South Dakota Driver License Manual, Handbook p. 19

7. If angry or upset, give yourself time to cool off before driving.

   Source: Handbook p. 22

   “If angry or excited, give yourself time to cool off.”
   South Dakota Driver License Manual, Handbook p. 22

8. Never drive around lowered railroad gates or try to beat a train.

   Source: Handbook p. 22

   “Driving around lowered gates or trying to beat the train can be fatal.”
   South Dakota Driver License Manual, Handbook p. 22

Numbers to know

3 questions from the South Dakota practice test

1. 1. In South Dakota, which driving action belongs in the aggressive-driving category?

   1. Checking mirrors before changing lanes
   2. Stopping behind a marked stop line
   3. Following too closely or making unsafe lane changes
   4. Yielding to pedestrians in a crosswalk
   Show answer

   Following too closely or making unsafe lane changes. The manual identifies behaviors such as speeding, close following, unsafe lane changes, poor signaling, and disobeying controls as aggressive driving patterns. Mirror checks and yielding are defensive behaviors, not examples of aggression. A cue is intentional pressure on others, such as crowding a bumper or darting between lanes to gain position. Aggressive driving is about dangerous intentional behavior, so do not answer with a normal skill like mirror checking.

2. 2. What kind of windshield or mirror clutter should a South Dakota driver avoid?

   1. Sun visors that remain above the windshield line
   2. Any factory rearview mirror adjustment
   3. Clean paper towels kept inside the vehicle
   4. Objects that block the driver's view
   Show answer

   Objects that block the driver's view. South Dakota's visibility advice is direct: do not hang items from the mirror or crowd the windshield with decals when they can block your view. A factory mirror adjustment is not the problem; the issue is extra material in the sight line. Before driving, use the cue of your forward view through the glass and remove anything that hides pedestrians, signals, or the edge of the road.

3. 3. What condition should your windshield wipers be in before driving in rain or snow?

   1. They may be skipped if the windshield is recently cleaned
   2. They only need to function on the driver's side
   3. They should work well and clear water properly
   4. They should be replaced only after winter ends
   Show answer

   They should work well and clear water properly. South Dakota treats wipers as part of keeping the vehicle safe to operate. They should be in good condition, and blades that do not clear water well should be replaced. The driver's-side-only choice is too narrow because poor clearing anywhere can reduce visibility. Use the cue of streaking, skipping, or water left on the glass; those signs mean maintenance is needed before bad weather driving.

Source: the South Dakota Driver License Manual, Be in Shape to Drive. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.