District of Columbia CDL: General Knowledge Practice Test

Not quite. The answer is One block

While driving, you should scan the road 12–15 seconds ahead. At typical speeds in urban areas, your vehicle will travel about one block in 12–15 seconds. At 60 mph, your vehicle will travel a quarter of a mile in 15 seconds.

Not quite. The answer is a third party

Lumpers (freight handlers) are persons usually employed by a third party to unload cargo from the truck at the receiver. Lumpers are tasked with operating the unloading equipment, such as fork lifts and pallet jacks, so you won't have to do this. The fee for using lumpers should be charged to the carrier; it is illegal under US law for you to be forced to eat the cost yourself.

Source: 49 US Code § 14103

Not quite. The answer is Both of the above

Your service brakes are designed to bring your vehicle to a safe, controlled stop. To test this, first release the parking brake. Pull forward at 5 mph and then apply the service brake. Check that the service brakes work properly and your vehicle does not pull to one side. This test can be performed with either air brakes or hydraulic brakes.

Not quite. The answer is Neither (a) nor (b)

If you're starting off your vehicle on an incline, take several steps to keep from rolling back. If you have a manual transmission vehicle, partly engage the clutch before you take your right foot off the brake. Apply the parking brake whenever necessary to keep from rolling back. Release the parking brake only when you have applied enough engine power to keep from rolling back. On a combination vehicle equipped with a trailer brake hand valve, the hand valve can be applied to keep from rolling back.

Not quite. The answer is read the weight limit sign.

The maximum weight will be posted in advance of a bridge. After going over a bridge, you may be asked to tell the examiner what the posted weight limit was.

Not quite. The answer is 3/8-G30; 2,650 pounds

Welded steel chain that is not marked or labeled with a grade or working load limit (WLL) is considered to have a WLL equal to that of grade 30 proof coil chain. Hence, each size 3/8" chain should be marked "3/8-G30." According to the WLL table in federal regulation 49 CFR 393.108, size 3/8" proof coil chain with grade 30 has a WLL of 2,650 pounds.

Not quite. The answer is one-half.

On a slippery road surface, your vehicle's wheels will have less traction, and the vehicle's braking distance will increase significantly. On wet roads, reduce your speed by about one-third. On snow, reduce your speed by about one-half. On ice, slow down to a crawl and stop driving altogether if possible. (On ice, your vehicle's braking distance may increase tremendously.)

Not quite. The answer is coercion.

Federal regulations define "coercion" as when a motor carrier, shipper, receiver, or transportation intermediary threatens to withhold work from, take employment action against, or punish a driver for refusing to operate in violation of federal regulations. The FMCSA's Coercion Rule explicitly prohibits motor carriers, shippers, receivers and transportation intermediaries from coercing drivers to operate in violation of certain FMCSA regulations. If you have been the victim of such coercion, you can file a coercion complaint with FMCSA, but you must do it within 90 days of when the coercion took place.

Not quite. The answer is The driver's chances of an accident increase.

As a driver's blood alcohol concentration (BAC) increases, the driver is less and less capable of driving safely. At a BAC of 0.05%, the driver's coordination starts to become impaired. At 0.08%, there is definite impairment of judgment and coordination. At 0.10%, the driver's reaction time increases. At 0.30%, there is a good chance that the driver will pass out.

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 For all of the above reasons

There are several reasons to cover your cargo, including protecting other people and the cargo itself. In addition, it will help you comply with regulations in several states.

Not quite. The answer is both of the above.

Each time you stop your vehicle during your trip, check the following: gauges, controls, mirrors, tires, lights, and securement of the cargo (if any). Use several of your senses—sight, hearing, feel, and smell—to detect signs of trouble.

Not quite. The answer is The length of a football field

For a tractor-trailer traveling at 55 mph on dry pavement, the typical perception distance is about 142 feet, the typical reaction distance is about 61 feet, and the typical braking distance is about 216 feet, for a total stopping distance of 419 feet. Air brake lag distance adds another 32 feet to this total. In comparison, the length of a football field (including the two end zones) is 360 feet.

Not quite. The answer is Brake shoes should not have oil, grease, or brake fluid on them.

The suspension system holds up the vehicle and its load, and keeps the axles in place. Therefore, broken or missing suspension parts can be extremely dangerous. Examples of such dangerous defects are a cracked spring hanger, a missing leaf spring, and a damaged frame member. Brake linings must not be loose or soaked with oil or grease. A brake lining that is soaked with oil or grease may indicate a leaking wheel seal. Replace the lining and check the wheel seal for leaks.

Not quite. The answer is Allow injured persons to become chilled or overheated.

If qualified medical personnel are at the accident scene, stay out of their way unless they ask for help. If they haven't arrived yet, try to keep injured persons warm (but neither chilled nor overheated). Don't move them unless there is a danger of fire or another accident from passing traffic.

Not quite. The answer is tire changing equipment.

Your vehicle must be equipped with a properly charged fire extinguisher and warning devices (flares, fusees, or reflective triangles). Optional emergency equipment can include tire chains in certain climates, tire changing equipment, emergency phone numbers, and an accident reporting packet.

Not quite. The answer is Differential

A differential uses a series of gears to accomplish several functions. First, it transfers torque from the driveshaft to the axle. Because the axle is at 90 degrees from the driveshaft, the differential also turns the torque by 90 degrees accordingly. The outside of a curved road is longer than the inside. On such a curve, the differential lets the outside half of the axle turn faster than the inside half of the axle, so that the outside wheels can cover a greater distance than the inside wheels. If there were no differential, the outside wheels would turn at the same rate as the inside wheels, causing at least some of the wheels to drag on the pavement.

Not quite. The answer is All of the above are true.

49% of CMV drivers smoke, compared with 27% of the general adult population. 73% of CMV drivers are obese, compared with 33% of the general population. 33% of CMV drivers have hypertension (high blood pressure), compared with 26% of the general population. Finally, only 8% of CMV drivers exercise regularly, compared with 25% of the general population.

Not quite. The answer is because you have blind spots.

It is important to use a helper when you are backing since you will be dealing with blind spots that you cannot see. Before you start, the two of you should agree on a set of hand signals - especially "Stop."

Not quite. The answer is Do all of the above.

Sadly, the valuable cargo that you're carrying makes you a target for criminals. Take a variety of steps to ensure your safety at truck stops. First, study reviews of truck stops written by other drivers, and try to avoid truck stops that have been reported as dangerous. At a truck stop, park in a well-lit area, and lock the cab doors and cargo doors on your vehicle. Hide valuables in the cab from view. Let your carrier know where you'll be staying. Don't talk about the cargo that you're carrying; some criminal might overhear you.

Source: "Truck Stop Guide: Safety Tips and Tricks for Truckers," LubeZone, August 4, 2021