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CDL General Knowledge Test · CDL General Knowledge Test

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CDL General Knowledge Test Seeing and Communicating Summary

Importance
★★★★☆ (4 / 5)
Weight
About 6 of 50 CDL General Knowledge Test questions (12%)

Looking 12 to 15 seconds ahead, using flat and convex mirrors, signaling early, flashing brake lights to warn drivers behind, and placing warning devices when you stop.

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Seeing and Communicating: must-know points

  • Look 12 to 15 seconds ahead: about one block in town and about a quarter mile on the highway.
  • Convex mirrors make things look smaller and farther away than they are.
  • Put out warning devices within 10 minutes of stopping on a road or shoulder.
  • On a two-way road: within 10 feet of the front or rear corner, plus 100 feet behind and 100 feet ahead.

Seeing and Communicating: 7 sample questions

Practice questionReviewedCDL General Knowledge Test › Seeing and Communicating★★★★☆

Question 1. How far ahead should you look while driving?

  1. ① 4 to 5 seconds ahead
  2. ② 30 to 40 seconds ahead
  3. ③ 12 to 15 seconds ahead
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Answer: ③ 12 to 15 seconds ahead

Key point: Look 12 to 15 seconds ahead

Good drivers look 12 to 15 seconds ahead. In town that is about one block. On the highway it is about a quarter of a mile. Keep shifting your eyes between near and far.

Wrong choices

  • 4 to 5 seconds ahead: This is not far enough. You may have to stop or change lanes suddenly.
  • 30 to 40 seconds ahead: This is farther than the rule. You also need to watch closer things.
Practice questionReviewedCDL General Knowledge Test › Seeing and Communicating★★★★☆

Question 2. How do objects look in a convex (curved) mirror?

  1. ① Smaller and farther away than they really are
  2. ② Larger and closer than they really are
  3. ③ Exactly the same as in a flat mirror
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Answer: ① Smaller and farther away than they really are

Key point: Convex mirror: smaller and farther away

Convex mirrors show a wider area than flat mirrors. But everything looks smaller and farther away than it really is. Allow for this when you judge space.

Wrong choices

  • Larger and closer than they really are: This is the opposite of what a convex mirror does.
  • Exactly the same as in a flat mirror: Convex mirrors show a wider area but change how things look.
Practice questionReviewedCDL General Knowledge Test › Seeing and Communicating★★★★☆

Question 3. You must stop on the shoulder of a highway. How soon must you put out your warning devices?

  1. ① Within 30 minutes
  2. ② Within 10 minutes
  3. ③ Only after dark
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Answer: ② Within 10 minutes

Key point: Put out warning devices within 10 minutes

When you stop on the road or shoulder, turn on your four-way flashers and put out your warning devices within 10 minutes, day or night.

Wrong choices

  • Within 30 minutes: 30 minutes is too long. Federal rules require 10 minutes.
  • Only after dark: You must put them out day or night.
Practice questionReviewedCDL General Knowledge Test › Seeing and Communicating★★★★☆

Question 4. You stop on a two-lane road with traffic in both directions. Where should you place your three warning triangles?

  1. ① One within 10 feet of the front or rear corner, one 100 feet behind, and one 100 feet ahead
  2. ② At 10 feet, 100 feet, and 200 feet behind the vehicle
  3. ③ All three right next to the rear bumper
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Answer: ① One within 10 feet of the front or rear corner, one 100 feet behind, and one 100 feet ahead

Key point: Two-way road: 10 ft, 100 ft behind, 100 ft ahead

On a two-lane road with traffic both ways (or an undivided highway), place warning devices:

  1. Within 10 feet of the front or rear corner to mark the vehicle
  2. 100 feet behind the vehicle
  3. 100 feet ahead of the vehicle

Wrong choices

  • At 10 feet, 100 feet, and 200 feet behind the vehicle: That pattern is for a one-way or divided highway.
  • All three right next to the rear bumper: Drivers would not get enough warning.
Practice questionReviewedCDL General Knowledge Test › Seeing and Communicating★★★★☆

Question 5. You stop on a divided highway. Where should you place your warning triangles?

  1. ① 10 feet from the corner, 100 feet behind, and 100 feet ahead
  2. ② At 10 feet, 100 feet, and 200 feet toward approaching traffic
  3. ③ At 50 feet, 500 feet, and 1,000 feet behind the vehicle
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Answer: ② At 10 feet, 100 feet, and 200 feet toward approaching traffic

Key point: Divided road: 10, 100, 200 ft toward traffic

On a one-way or divided highway, traffic comes from only one direction. Place the warning devices 10 feet, 100 feet, and 200 feet back toward the approaching traffic.

Wrong choices

  • 10 feet from the corner, 100 feet behind, and 100 feet ahead: That pattern is for a two-way road.
  • At 50 feet, 500 feet, and 1,000 feet behind the vehicle: These distances are not the rule.
Practice questionReviewedCDL General Knowledge Test › Seeing and Communicating★★★★☆

Question 6. You see a hazard ahead that will make you slow down. How should you warn drivers behind you?

  1. ① Turn on your high beams
  2. ② Wave your arm out the window
  3. ③ Tap the brake pedal lightly a few times to flash the brake lights
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Answer: ③ Tap the brake pedal lightly a few times to flash the brake lights

Key point: Flash brake lights to warn drivers behind

Drivers behind a large vehicle often cannot see what is ahead. A few light taps on the brake pedal flash your brake lights and warn them you will slow down. Use four-way flashers when you are driving very slowly or are stopped.

Wrong choices

  • Turn on your high beams: High beams do not warn drivers behind you.
  • Wave your arm out the window: Drivers behind a large vehicle may not see your arm.
Practice questionReviewedCDL General Knowledge Test › Seeing and Communicating★★★★☆

Question 7. A driver behind you seems to want to pass. Should you wave them by when the road ahead looks clear?

  1. ① Yes. Truck drivers can see farther ahead, so it helps them
  2. ② Yes, but only by flashing your turn signal
  3. ③ No. Do not direct traffic. You could cause a crash and be blamed for it.
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Answer: ③ No. Do not direct traffic. You could cause a crash and be blamed for it.

Key point: Never signal other drivers to pass

Some drivers try to help by signaling when it is safe to pass. Do not do this. You could cause a crash, and you could be blamed for it.

Wrong choices

  • Yes. Truck drivers can see farther ahead, so it helps them: You may misjudge, and the driver may crash on your signal.
  • Yes, but only by flashing your turn signal: Signaling others to pass is still directing traffic.

Test yourself.

Seeing and Communicating: 5 questions →CDL General Knowledge Test: 5 questions →