Following distance, passing and large vehicles

Key points

1. Keep a minimum following distance of 4 seconds behind the vehicle in front.

   Source: Handbook p. 51

   “Always try to keep a minimum following distance of 4 seconds between your car and the vehicle in front.”
   South Dakota Driver License Manual, Handbook p. 51

2. You are too close if you pass the fixed point before counting to one thousand four.

   Source: Handbook p. 51

   “You are following too closely if you pass the stationary point before counting to one thousand four.”
   South Dakota Driver License Manual, Handbook p. 51

3. At night add at least 1 second of following distance, and at least 2 on unfamiliar roads at night.

   Source: Handbook p. 66

   “Increase the following distance by adding at least one additional second for night driving conditions and at least two additional seconds for driving on unfamiliar roadways at night.”
   South Dakota Driver License Manual, Handbook p. 66

4. Passing safely needs over 1600 feet, about one third of a mile, of clear road.

   Source: Handbook p. 53

   “That means you need over 1600 feet or about one-third of a mile to pass safely.”
   South Dakota Driver License Manual, Handbook p. 53

5. As a rule, pass only one vehicle at a time and pass on the left.

   Source: Handbook p. 53

   “As a rule, pass only one vehicle at a time and pass on the left side.”
   South Dakota Driver License Manual, Handbook p. 53

6. Return to your lane after passing when you can see both headlights of the passed vehicle in the mirror.

   Source: Handbook p. 53

   “When you can see both headlights of the vehicle you have just passed in your rearview mirror, it is safe to return to the driving lane.”
   South Dakota Driver License Manual, Handbook p. 53

7. Truck No Zones: a car can vanish up to 20 feet in front of the cab and up to 200 feet behind.

   Source: Handbook p. 56

   “A car can disappear from their view while it is up to 20 feet in front of the cab, on either side of the truck (especially alongside the cab), and up to 200 feet behind!”
   South Dakota Driver License Manual, Handbook p. 56

8. If you cannot see the truck driver in their side mirror, they cannot see you.

   Source: Handbook p. 56

   “if you can’t see the truck or bus driver in their side mirror, they can’t see you.”
   South Dakota Driver License Manual, Handbook p. 56

9. A loaded truck at 55 mph needs at least 335 feet to stop, more than one and a half times a car's distance.

   Source: Handbook p. 63

   “traveling at 55 mph requires a minimum of 335 feet before coming to a complete stop, or greater than 1½ times the stopping distance of a car.”
   South Dakota Driver License Manual, Handbook p. 63

10. If tailgated with no right lane, wait until the road ahead is clear and passing is legal, then slowly reduce speed.

    Source: Handbook p. 52

    “If there is no right lane, wait until the road ahead is clear and passing is legal, then slowly reduce speed.”
    South Dakota Driver License Manual, Handbook p. 52

Numbers to know

3 questions from the South Dakota practice test

1. 1. What following distance should you normally keep behind the vehicle ahead?

   1. One car length for every 20 mph of speed
   2. A minimum of 4 seconds
   3. At least 2 seconds in town and 3 seconds on highways
   4. Close enough to read the rear license plate
   Show answer

   A minimum of 4 seconds. South Dakota teaches a minimum 4 second following distance for ordinary driving. That time gap gives you room to notice a problem, react, and brake without relying on the driver ahead to keep moving. The 2 or 3 choice “At least 2 seconds in town and 3 seconds on highways” is tempting because older advice often used shorter gaps, but it is not the standard in this manual. Pick a roadside object, start counting when the rear of the lead vehicle passes it, and stay back until your count reaches four.

2. 2. How does the South Dakota manual define a truck's No-Zone?

   1. The lane reserved for trucks on hills
   2. The 100 feet directly in front of a truck only
   3. Any area where trucks are prohibited
   4. The areas around trucks and buses where cars disappear into blind spots or are so close they restrict the driver's ability to stop or maneuver
   Show answer

   The areas around trucks and buses where cars disappear into blind spots or are so close they restrict the driver's ability to stop or maneuver. Trucks and buses have blind spots called No-Zones. The manual defines them as the areas around trucks and buses where cars disappear into blind spots or are so close that they restrict the truck or bus driver's ability to stop or maneuver safely. Both kinds greatly increase the potential for a crash. The No-Zone surrounds the vehicle on the sides, front and rear, not just ahead, and it has nothing to do with truck restrictions or hill lanes.

3. 3. Why should you avoid passing several vehicles at once?

   1. You should pass only one vehicle at a time as a general rule
   2. South Dakota allows passing only on gravel shoulders
   3. Multiple passes are allowed only within city limits
   4. You must wait for the driver behind to honk first
   Show answer

   You should pass only one vehicle at a time as a general rule. The manual advises passing only one vehicle at a time as a general rule. Multiple vehicles require a much longer opening and leave you exposed in the passing lane longer, especially if an oncoming vehicle appears or one of the vehicles ahead moves. The city limits choice invents an exception that is not part of the rule. A concrete cue is the length of the line ahead: if you cannot complete one clean pass and return safely, wait.

Source: the South Dakota Driver License Manual, Safe Driving Tips. 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.