District of Columbia CDL Practice Test

Not quite. The answer is All of the above

Once the temperature drops to freezing, some sections of the road will start to freeze before others. The first to freeze will be shaded areas and bridges. If the road appears wet, it may be covered in black ice – a thin layer of slippery ice through which you can see the actual road.

Not quite. The answer is True

Cargo that is piled up high raises a vehicle's center of gravity, making the vehicle top-heavy and therefore more prone to rollovers. This is especially true if the heaviest parts of the cargo are near the top. You can lower the center of gravity by placing the heaviest parts of the cargo underneath the lightest parts.

Not quite. The answer is Leave your high beams on.

To avoid blinding other drivers, dim your headlights whenever you're within 500 feet of an oncoming vehicle or within 500 feet of a vehicle you are following.

Not quite. The answer is True

Tires that overheat can catch fire. Underinflation causes increased flexing of the tire, which increases tire temperature.

Not quite. The answer is when a wheel may lock up.

Hard braking risks locking the wheels, resulting in a skid. An antilock braking system (ABS) is a computerized system that keeps your wheels from locking up during hard braking. A sensor at each wheel monitors how fast the wheel is turning and sends that information to a central electronic control unit (ECU), which acts like a little computer. As you're applying the brakes, if the ECU determines that one wheel is rotating much slower than the other wheels (indicating it may be about to lock up), it releases the brake on that wheel to let it turn freely. Then it reapplies the brake.

Not quite. The answer is The consistency of the concrete to be poured

"Slump" is a measure of the consistency of fresh concrete. You measure slump by forming a sample of the concrete into a standard-shaped 12-inch-high cone, and measuring how far the cone "slumps" (i.e., how much its height declines). The more it slumps, the thinner the consistency of the concrete. For example, concrete with a 5-inch slump is thinner than concrete with a 3-inch slump.

Not quite. The answer is two red flags

Under federal regulations, if the load is more than two feet wide and extends more than four feet behind the rear of the CMV, two square red flags, each 18 inches square, must be placed at the end of the load. If the load is no more than two feet wide, one square red flag will suffice. There are additional requirements on illuminating the load at night. US states may impose their own additional requirements on the transportation of oversized loads. You can learn about Washington, DC's requirements by contacting the District Department of Transportation or visiting their webpage "Oversize and Overweight Vehicles" (https://ddot.dc.gov/node/482382). [49 CFR 393.11],

Source: 49 CFR 393.87

Not quite. The answer is avoid braking until your speed has decreased to about 20 mph.

If you've moved onto a shoulder that may have a loose surface, let your vehicle slow down to about 20 mph before you brake. Braking at a higher speed on a loose surface can cause a skid.

Not quite. The answer is from the time that your eyes see something, to the time that your brain recognizes it.

Perception distance is the distance that your vehicle travels from the time that your eyes see something, to the time that your brain recognizes it. For the average alert driver, this time is about 1¾ seconds. Reaction distance is the distance that your vehicle travels from the time that your brain decides to brake, to the time that you start to press the brake pedal. For the average driver, this time is about ¾ second to 1 second.

Not quite. The answer is All of the above

If you must drive through a tunnel, there are several issues you must deal with. First, make sure that the tunnel is tall enough for your vehicle to get through it safely. Plan in advance. Know the height of your CMV and the height of the tunnel ceiling. Second, tunnels often have reduced lane widths. Your CMV may be 8½ feet wide. Drive with caution and watch the sides of your vehicle. Finally, there can be strong winds inside the tunnel, and strong crosswinds as you exit the tunnel.

Not quite. The answer is 14 consecutive 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 There are “blind spots” that your mirrors cannot show.

"Blind spots" are areas around your vehicle that your mirrors cannot show you. Large CMVs have large blind spots to the front, the rear, and both sides of the vehicle. Convex mirrors can show a wider area than flat mirrors, but at the expense of making objects appear smaller and farther away than they would in a flat mirror.

Not quite. The answer is If you do not hold the steering wheel with both hands, it could pull out of your grasp.

Hold the steering wheel firmly with both hands. Your hands should be on opposite sides of the steering wheel. If you hold the steering wheel with just one hand, it could pull out of your grasp if a front tire fails or you hit a pothole or the curb.

Not quite. The answer is Yes.

Because of the limited visibility, avoid backing up whenever possible. If you must back your vehicle, use a helper if possible. The helper can stand near the rear of your vehicle and keep an eye on your blind spots. He or she can signal you to stop before an accident can occur.

Not quite. The answer is centered.

It's best to keep your cargo centered in the cargo area. Too much weight to the front can cause steering problems. Too much weight to the rear can reduce traction available to the drive wheels. Too much weight to one side increases the chance of a rollover.

Not quite. The answer is 150 miles

A short-haul driver is exempt from the Hours of Service regulations, if he or she meets all the following requirements: (1) the driver operates within a 150-mile radius of the driver's home terminal or yard; (2) the driver goes off duty within 14 consecutive hours of work; (3) each 14 hours on duty is followed by at least 10 off-duty hours for a truck driver or 8 off-duty hours for a bus driver; and (4) the driver's employer keeps accurate records of the driver's duty status for the next six months.

Source: 49 CFR 395.1

Not quite. The answer is 4/32 inch

Front steering tires require 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 To turn quickly, keep a firm grip on the steering wheel.

In an emergency, stopping may not be the safest thing to do. The stopping distance of your vehicle at high speed can be longer than a football field. If you don't have enough room to stop, you may have to steer away from the hazard. Remember, you can almost always turn to miss an obstacle more quickly than you can stop. To turn quickly, you must have a firm grip on the steering wheel with both hands.

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 Get out of the driver's way.

First and foremost, make every attempt to get out of the driver's way. Don't let your pride or ego keep you from doing this. Don't challenge the aggressive driver by speeding up or attempting to hold your own in your travel lane.