Arizona CDL Knowledge Test Class A: Practice Test

Tire load is defined as the maximum safe weight that a tire can carry at a specified pressure.

If you must drive so slowly that you will impede the flow of traffic, you should turn on your four-way flashers to alert drivers behind you (as long as local laws allow the use of flashers).

After a vehicle is started, the warning lights and buzzers should go out after a few seconds. If the warning signals do not turn off, there may be something wrong with the vehicle.

There should be at least 4/32 of an inch of tread depth in every major groove on front tires and 2/32 of an inch on other tires. Valve stems should not be cut or cracked. Tire sizes should not be mismatched.

You may be able to tell that another driver is distracted if you can see them drifting within a lane or across lane dividers; traveling at inconsistent speeds; being preoccupied with a cell phone, a map, food, or other items; or engaging in conversation with passengers.

The air compressor of an air brake system is connected to the engine through gears or a v-belt. The compressor may be air-cooled or cooled by the engine cooling system.

When driving through a work zone, follow the posted speed limits. If workers are present, you should slow to a speed that is even lower than the posted limit.

In an air brake system, the air compressor pumps air into the air storage tanks. The air compressor is controlled by the air compressor governor.

Roads are particularly slippery when it first begins to rain. The water mixes with oil drippings on the road that have not yet washed away, creating a slippery and dangerous mixture.