South Carolina CDL — General Knowledge: Signals & Pavement Markings Practice Test

Question 1

Should you have to stop on the roadway or shoulder, how soon must the emergency warning devices be set out?

Accepted Answer

Within ten minutes — When you stop on a road or shoulder, you are required to set out your warning devices within ten minutes.

Answer

Within thirty seconds

Answer

Only if the stop lasts over an hour

Answer

Within thirty minutes

Question 2

The manual recommends dimming your high beams when an oncoming vehicle is within what distance?

Accepted Answer

Within 500 feet — You should lower your high beams before they cause glare, which means dimming within 500 feet of an oncoming vehicle.

Answer

Within 100 feet

Answer

Within 250 feet

Answer

Within 1,000 feet

Question 3

After you stop on a two-way road that carries traffic in each direction, where should the warning devices go?

Accepted Answer

One near the vehicle, and one about 100 feet ahead and behind — On a two-way road, put one device within 10 feet of the vehicle to mark it and one about 100 feet ahead and one 100 feet behind.

Answer

All three within 10 feet of the front bumper

Answer

At 200, 300, and 500 feet behind only

Answer

Only a single device at the rear corner

Question 4

Why should a commercial driver turn on the turn signal well before making a turn?

Accepted Answer

To discourage other drivers from trying to pass you — Signaling early is the best way to keep other drivers from trying to pass you as you begin the turn.

Answer

To let you turn without slowing at all

Answer

To satisfy a rule that the signal blink a set number of times

Answer

To make it legal to swing wide into the next lane

Question 5

As a best practice, you should also dim your high beams when following another vehicle within what distance?

Accepted Answer

Within 500 feet of the vehicle ahead — The manual recommends dimming your lights within 500 feet when you are following another vehicle so your beams do not glare in its mirrors.

Answer

Within 50 feet of the vehicle ahead

Answer

Only after you are directly behind its bumper

Answer

There is never a need to dim while following

Question 6

How can a large-vehicle driver warn following traffic that a slowdown is coming?

Accepted Answer

Lightly tap the brake pedal to flash the brake lights — Lightly tapping the brakes a couple of times flashes your brake lights and tells drivers behind that a slowdown is coming.

Answer

Wave an arm out the driver's window

Answer

Switch the headlights from low to high beam

Answer

Sound a long blast on the horn

Question 7

When you stop on a road where a hill or curve blocks the view, how should you adjust the placement of your rearmost warning device?

Accepted Answer

Move it farther back beyond the obstruction to warn drivers in time — Move the rearmost triangle farther back beyond the hill or curve so drivers get warning within 500 feet, since the obstruction hides your vehicle.

Answer

Move it closer to the bumper for visibility

Answer

Remove it entirely since the curve hides it

Answer

Stack it on top of the nearest device

Question 8

After finishing a turn in a vehicle without self-canceling signals, what should the driver remember to do?

Accepted Answer

Cancel the signal so it stops blinking — Once the turn is complete, turn off the signal so it does not mislead other drivers about your next move.

Answer

Switch it to the four-way flashers

Answer

Leave it flashing until the next intersection

Answer

Tap the brakes twice to reset it

Question 9

While setting out reflective triangles, how should you position yourself relative to oncoming traffic?

Accepted Answer

Keep the triangles between you and the approaching traffic — Hold the triangles between yourself and the oncoming traffic so approaching drivers can see you as you place them.

Answer

Toss the triangles into place from the shoulder

Answer

Walk with your back to the traffic to move faster

Answer

Stand in the traffic lane facing away

Question 10

Why does the manual advise keeping your turn signal on continuously through a turn?

Accepted Answer

So you can keep both hands on the wheel through the turn — Turning safely takes both hands, so keep the signal running until the turn is done rather than shutting it off too soon.

Answer

Because the horn will not work otherwise

Answer

So the brake lights stay lit the whole time

Answer

Because the signal must run for exactly one minute

Question 11

If you must stop on or beside a one-way or divided highway, where should you set out your three warning devices?

Accepted Answer

At 10, 100, and 200 feet toward oncoming traffic — On such a highway, set the three markers toward oncoming traffic at roughly 10, 100, and 200 feet back from the vehicle.

Answer

All three grouped directly behind the bumper

Answer

At 25, 50, and 75 feet ahead of the vehicle

Answer

At 50, 150, and 300 feet on each side

Question 12

When is it appropriate to switch on your four-way emergency flashers?

Accepted Answer

When you are moving very slowly or stopped — Switch on the four-way flashers any time your vehicle is barely moving or halted, to warn other traffic of your low speed.

Answer

Every time you make a routine lane change

Answer

Only when your headlights have failed

Answer

Whenever you enter a passing zone

Signals & Pavement Markings

Study questions with answers

1. Should you have to stop on the roadway or shoulder, how soon must the emergency warning devices be set out?

2. The manual recommends dimming your high beams when an oncoming vehicle is within what distance?

3. After you stop on a two-way road that carries traffic in each direction, where should the warning devices go?

4. Why should a commercial driver turn on the turn signal well before making a turn?

5. As a best practice, you should also dim your high beams when following another vehicle within what distance?

6. How can a large-vehicle driver warn following traffic that a slowdown is coming?

7. When you stop on a road where a hill or curve blocks the view, how should you adjust the placement of your rearmost warning device?

8. After finishing a turn in a vehicle without self-canceling signals, what should the driver remember to do?

9. While setting out reflective triangles, how should you position yourself relative to oncoming traffic?

10. Why does the manual advise keeping your turn signal on continuously through a turn?

11. If you must stop on or beside a one-way or divided highway, where should you set out your three warning devices?

12. When is it appropriate to switch on your four-way emergency flashers?

More CDL — General Knowledge topics

Practice Signals & Pavement Markings in another state