Illinois CDL: General Knowledge Practice Test

Not quite. The answer is 35 mph.

It's usually safest to drive at the speed of traffic rather than constantly pass other vehicles or invite other drivers to pass you. However, if there are lower speed limits posted for CMVs, obey them.

Not quite. The answer is To provide power to the cab while the engine is off

A power take-off (PTO) is a device that can transfer power from the idling engine to some secondary application, such as an implement or hydraulic pump. For example, a PTO can raise or lower the bed of a dump truck. An auxiliary power unit (APU) provides electrical power to run your cab's heater, A/C, and appliances without idling the engine. Idling the engine produces air pollution, so most states limit how long you can idle your engine (although they may make an exception for operating a PTO).

Not quite. The answer is 30 days.

You must notify your employer within 30 days of conviction for any traffic violation except parking, even if you weren't driving a CMV at the time. Legally, paying the fine on a traffic ticket constitutes an admission of guilt: you are waiving your right to challenge the ticket in court.

Not quite. The answer is All of the above

Some prescription medications and some over-the-counter cold medicines may cause drowsiness. Always check the label. If you're still unsure, ask your pharmacist or doctor before taking them.

Not quite. The answer is All of the above

A skid occurs when the tires lose their grip of the road. This can happen in any of four ways: (1) Over-braking: Braking too hard and locking the wheels. Skids can also occur if you use the speed retarder on a slippery road. (2) Over-steering: Turning the wheels more sharply than the vehicle can turn. (3) Over-acceleration: Supplying too much power to the drive wheels, causing them to spin. (4) Driving too fast: Most serious skids result from driving too fast for road conditions.

Not quite. The answer is Rough acceleration can cause mechanical damage.

From a stopped position, accelerate smoothly and gradually. Jerking forward or rough acceleration can cause mechanical damage (possibly including damage to the coupling if you're pulling a trailer).

Not quite. The answer is 11 hours

According to the Hours of Service (HOS) regulations, the driver of a cargo-carrying vehicle must not drive after a period of 14 consecutive hours after coming on duty following 10 consecutive hours off duty. The driver may not drive for more than 11 hours during this on-duty period.

Source: "Summary of Hours of Service Regulations," FMCSA, https://www.fmcsa.dot.gov/regulations/hours-service/summary-hours-service-regulations

Not quite. The answer is Stop and sleep.

The only way to overcome sleep debt is to sleep. Don't take any chances and don't try to beat nature, especially not with drugs or pills.

Not quite. The answer is Both of the above are correct.

Cargo that is not secured properly can fall off your vehicle, possibly creating road hazards or injuring other road users. Loose cargo can move or shift forward in a quick stop or crash, possibly injuring you or your passengers.

Not quite. The answer is are caused by driving too fast or trying to stop too quickly.

Over-braking and over-steering can cause skids. Both over-braking and over-steering are more likely when you're driving too fast.

Not quite. The answer is Upshift.

If your hydraulic brakes fail while you're driving, try pumping the brake pedal to build up enough hydraulic pressure to stop your vehicle. If this fails, downshift to use engine braking and apply the parking brake. Release the parking brake before you lock the wheels. If all else fails, look for an escape route. Head for an escape ramp or an open field and let your vehicle slow to a stop.

Not quite. The answer is Both of the above

When changing lanes, check your mirrors at each of the following times: (1) before you change lanes, to make sure there is enough room; (2) after you have signaled, to check that no one has moved into your blind spot; (3) right after you start the lane change, to double-check that your path is clear; and (4) after you complete the lane change.

Not quite. The answer is Underinflated tires and dual tires that touch

Tires that overheat can catch fire. Underinflation causes increased flexing of the tire, which increases tire temperature. Dual tires that touch each other or other parts of the vehicle can overheat due to friction.

Not quite. The answer is Windshield washer antifreeze should be used.

Prevent your windshield from freezing in cold weather. Fill your windshield washer reservoir with a windshield washer antifreeze that is rated for the cold temperatures in which you expect to be driving.

Not quite. The answer is Signal before you change lanes, and change lanes slowly and smoothly.

To change lanes, (1) make the necessary traffic checks first; (2) give the proper signals; and (3) smoothly change lanes when it is safe to do so.

Not quite. The answer is Tires of mismatched sizes should not be used on the same vehicle.

Tires should never be mismatched in size or type. Radial tires and bias-ply tires should not be used together on the same vehicle. Steering axle tires must have a tread depth of at least 4/32 inch. All other tires must have a tread depth of at least 2/32 inch.

Not quite. The answer is 66,000 pounds

To avoid overloading bridges, a bridge formula is used to specify a lower maximum axle weight for axles that are closer together. The Federal Gross Bridge Weight formula is W = 500 ( L N / (N - 1) + 12 N + 36 ) where W is the maximum allowed weight of a group of axles (rounded off to the nearest 500 pounds), L is the distance between the outer axles of the group, and N is the number of axles in the group. "L N" means L multiplied by N, and "12 N" means 12 multiplied by N. In this case, we consider the drive axles and trailer axles as one group of 4 axles. Therefore, N equals 4. The distance between the outer axles of this group is 36 feet. Therefore, L = 36. L × N = 144. N - 1 = 3. 144 divided by 3 = 48. 12 × N = 48 also. 48 + 48 + 36 = 132. Multiply this figure by 500 to get 66,000 pounds. Finally, round off the result to the nearest 500 pounds, which in this case is still 66,000 pounds.

Source: 23 CFR 658.17

Not quite. The answer is Under wet or icy road conditions

Retarders can slow your vehicle on a downgrade so you can avoid straining the service brakes. Many retarders can absorb as much or more horsepower as the engine can develop. But when the drive wheels have poor traction (such as on a slippery surface), some retarders can cause the drive wheels to lock, which can result in a skid. Therefore, you should turn the retarder off whenever the road is wet, icy, or snow covered.

Not quite. The answer is restore traction to the tires.

If braking or steering force exceeds the tires' traction with the road surface, a skid may result. You can recover from the skid by restoring sufficient traction.

Not quite. The answer is Tie rod

Component A is the tie rod. The tie rod connects the left and right steering knuckles to each other so that the left and right front wheels will turn in unison.