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South Dakota driving lesson · Sharing the Road

Trucks and buses: No-Zones and stopping

A 3-minute lesson from the South Dakota course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.

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Read time
3 minutes
Course unit
Sharing the Road
Checkpoint questions
6
Source pages
59, 60

Trucks and buses are bigger and less maneuverable, need longer to stop and accelerate, and have much larger blind spots than cars. More than 250,000 crashes between cars and commercial vehicles happen each year.

250,000+

Crashes between cars and commercial vehicles each year

Handbook p. 59 ↗

Minimum stopping distances at 55 mph

Minimum stopping distances at 55 mph
VehicleDistance
Loaded truck, clear dry road (p.59)290 feet
Bus300 feet
Loaded truck, ideal conditions (p.60)335 feet, over 1.5 times a car
Handbook p. 59 ↗

No-Zone

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 safely.

Handbook p. 59 ↗

Know the rule

Side No-Zones are big on both sides; the right-side blind spot starts behind the cab and can extend the length of the truck. If you can't see the driver's face in the side mirror, the driver can't see you. Don't ride alongside longer than needed.

Handbook p. 60 ↗

Know the rule

Front No-Zone: don't enter the road or change lanes in front of a large vehicle. After passing, see its whole front in your rearview mirror before pulling in, and keep your speed.

Handbook p. 60 ↗

Know the rule

Rear No-Zone: the blind spot directly behind can extend up to 200 feet. Don't follow closely, and position your car where the driver can see it in the side mirrors.

Handbook p. 60 ↗

Know the rule

On steep hills large vehicles slow to about 35 mph and use the right lane. Avoid the right lane on hills and near truck weigh stations, where trucks re-enter faster traffic.

Handbook p. 60 ↗
Truck blind spots (No-Zones)
Truck No-Zones: front, sides and rear
Following too closely behind a truck
Too close behind a truck: you can't see ahead and it can't see you

Put it into practice

You're cruising beside a semi's right side, just behind the cab. That's its biggest blind spot. Either pass steadily or drop back until you can see the driver's face in their side mirror.

Check your understanding

Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.

The handbook's Large Trucks and Buses overview (p.59) says a loaded truck at 55 mph on a clear, dry road needs at least how far to stop?
  1. 500 feet
  2. 158 feet
  3. 100 feet
  4. 290 feet

Answer: 290 feet

The p.59 overview gives a minimum of 290 feet for a loaded truck at 55 mph (the p.60 No-Zone section cites 335 feet under ideal conditions).

Handbook p. 59 ↗
At 55 mph, buses may require a minimum stopping distance of about how far?
  1. 300 feet
  2. 158 feet
  3. 200 feet
  4. 500 feet

Answer: 300 feet

Buses may require a minimum of 300 feet to come to a complete stop at 55 mph.

Handbook p. 59 ↗
According to the Front No-Zone description, a loaded truck's stopping distance at 55 mph is roughly how many times that of a car?
  1. Over 1.5 times a car's stopping distance
  2. About the same as a car's
  3. Slightly less than a car's
  4. About three-quarters of a car's

Answer: Over 1.5 times a car's stopping distance

A loaded truck's front No-Zone stopping distance of about 335 feet at 55 mph is greater than 1.5 times a car's stopping distance.

Handbook p. 60 ↗
How can you tell if a truck driver cannot see you in their side mirror?
  1. If you can see the whole trailer
  2. If you can't see their face, they can't see you
  3. If you are more than 50 feet back
  4. If their turn signal is off

Answer: If you can't see their face, they can't see you

A good rule of thumb: if you can't see the truck driver's face in their side mirror, they can't see you.

Handbook p. 60 ↗
How far behind a large truck or bus can its rear No-Zone (blind spot) extend?
  1. Up to 200 feet
  2. Up to 50 feet
  3. Up to 20 feet
  4. Up to 500 feet

Answer: Up to 200 feet

Large vehicles have huge blind spots directly behind them that can extend up to 200 feet.

Handbook p. 60 ↗
Why should drivers avoid the right lane near truck weigh stations when possible?
  1. It is closed to all non-commercial vehicles
  2. It has a lower posted speed limit
  3. Large vehicles re-enter faster traffic there
  4. Weigh stations often have speed cameras

Answer: Large vehicles re-enter faster traffic there

Avoiding the right lane near weigh stations reduces the chance of a crash as trucks merge back into traffic.

Handbook p. 60 ↗
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