California CDL — General Knowledge: Road Signs Practice Test

Question 1

A small sign mounted underneath a crossbuck displays the numeral 2. What is it telling a commercial driver?

Accepted Answer

The roadway crosses two separate sets of rails here — Where a crossing spans more than one set of rails, a plate beneath the crossbuck gives the count. Knowing there are two tracks matters, because one train can easily screen another.

Answer

Two trains use this crossing every day

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You must remain stopped for two full seconds before proceeding

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The next crossing lies two miles further along

Question 2

What does a yellow, diamond-shaped road sign mean?

Accepted Answer

It warns of a hazard or change in the road ahead — Yellow diamond-shaped signs are warning signs. They alert you to a hazard or a change in the road ahead, such as a curve, an intersection, or a crossing, so you can slow down and prepare.

Answer

It shows the legal speed limit

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It marks a rest area for trucks

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It means the road is closed

Question 3

A round warning sign with a black X on a yellow field appears before you reach a set of railroad tracks. What is it telling you?

Accepted Answer

Reduce speed, watch and listen for a train, and be ready to halt at the rails — The yellow circular sign posted in advance of a public crossing is a warning. It asks you to cut your speed, check for an approaching train with both eyes and ears, and be ready to halt at the rails.

Answer

A train has already passed and the crossing is now clear

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Trucks above a posted weight must take the marked detour

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The tracks ahead have been permanently removed

Question 4

Signs at the top of a mountain descent state how long the grade runs and how steep it is. How should a commercial driver use that information?

Accepted Answer

To pick a safe speed and drop into a low gear before starting down — Those signs let you plan the descent before gravity takes over. Read them, settle on a speed you can hold, and get the transmission into a low gear at the top rather than partway down.

Answer

To decide whether a special permit is needed for the route

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To calculate how much fuel the descent will consume

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To confirm the weight rating of the bridge further ahead

Question 5

A bus driver reaches a railroad crossing posted with a sign reading EXEMPT. What does that sign allow?

Accepted Answer

The bus need not come to a full stop, but must still slow and check carefully — An exempt crossing releases a bus or a placarded vehicle from the mandatory stop. It does not release the driver from looking, so you still reduce speed and confirm that no train and no other traffic is a threat.

Answer

The bus may cross at its normal road speed without checking

Answer

The bus is exempt from the crossing rules but trucks are not

Answer

The bus must halt twice, once at each rail

Question 6

A sign posting a clearance such as "13 ft 6 in" at an underpass tells a truck driver what?

Accepted Answer

The maximum overhead clearance for your vehicle — It shows the maximum overhead clearance. Make sure your loaded vehicle's height is safely below the posted number, remembering that repaving or a tall load can reduce the real clearance.

Answer

The maximum weight allowed on the bridge

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The distance to the next exit

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The minimum speed on the ramp

Question 7

What is a driver being told by a sign at a bridge that gives a maximum weight?

Accepted Answer

The heaviest load that structure is rated to carry — Caltrans and local agencies post the weight a structure is rated to support, and that figure can be lower than the general legal limit for your vehicle. If your rig is heavier, take the alternate route offered.

Answer

The combined weight of every vehicle allowed on it at once

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The weight above which a toll becomes payable

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The weight at which a wide-load permit becomes necessary

Question 8

What does the white X-shaped crossbuck sign posted at a railroad crossing require of you?

Accepted Answer

It marks the crossing and obliges you to give any train the right-of-way — A crossbuck identifies the grade crossing itself. It carries a legal duty as well: any train using those tracks has priority, so you must let it pass before you cross.

Answer

It permits you to cross without slowing whenever no gate is present

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It applies only to buses and to vehicles carrying placards

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It marks the point where a highway changes its route number

Question 9

You come up behind a vehicle displaying a red triangle with an orange center. What does that emblem tell you?

Accepted Answer

The vehicle is not built to travel faster than 25 mph — That emblem marks a slow-moving vehicle. Under California law a vehicle carrying it is not built to reach speeds above 25 mph, so you will close the gap far faster than you expect.

Answer

The vehicle is hauling explosives

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The vehicle is disabled and is waiting for a tow

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The person at the wheel is a student in training

Question 10

A speed limit sign is posted on a curving freeway off-ramp. How should the driver of a heavily loaded truck treat that number?

Accepted Answer

As a limit set with cars in mind, which may still be too fast for a heavy load — Ramp speeds are posted with small vehicles in mind. A tall or heavy commercial vehicle can roll over well below that figure, so slow to a speed you know is safe before the curved part begins.

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As a figure that applies only during daylight hours

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As a minimum speed the truck must keep up on the ramp

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As a guaranteed safe speed for any legally loaded vehicle

Question 11

Diamond-shaped signs turned to stand on one point are fixed to the outside of a trailer. What information do they carry?

Accepted Answer

The hazard class of the material being hauled — Those diamonds are placards. They tell police, firefighters, and other drivers which hazard class the cargo belongs to, and a placarded vehicle carries four matching ones so the message can be read from any side.

Answer

The gross weight of the loaded trailer

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The states the carrier is authorized to enter

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The date of the trailer's last brake inspection

California CDL — General Knowledge: Road Signs practice test

Study questions with answers

1. A small sign mounted underneath a crossbuck displays the numeral 2. What is it telling a commercial driver?

2. What does a yellow, diamond-shaped road sign mean?

3. A round warning sign with a black X on a yellow field appears before you reach a set of railroad tracks. What is it telling you?

4. Signs at the top of a mountain descent state how long the grade runs and how steep it is. How should a commercial driver use that information?

5. A bus driver reaches a railroad crossing posted with a sign reading EXEMPT. What does that sign allow?

6. A sign posting a clearance such as "13 ft 6 in" at an underpass tells a truck driver what?

7. What is a driver being told by a sign at a bridge that gives a maximum weight?

8. What does the white X-shaped crossbuck sign posted at a railroad crossing require of you?

9. You come up behind a vehicle displaying a red triangle with an orange center. What does that emblem tell you?

10. A speed limit sign is posted on a curving freeway off-ramp. How should the driver of a heavily loaded truck treat that number?

11. Diamond-shaped signs turned to stand on one point are fixed to the outside of a trailer. What information do they carry?

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