Kansas CDL: General Knowledge Practice Test

Not quite. The answer is Flashing your brake lights to stop someone from tailgating

Use your headlights during times of lower visibility. Use your brake lights only to warn other drivers that you are preparing to slow down or stop, or there is a hazard ahead for which you'll have to slow down. If you're being tailgated, avoid such tricks as flashing your brake lights. Handle tailgaters in a different way: Keep right and increase your following distance.

Not quite. The answer is 320 feet

Distracted driving is dangerous. 55 mph equals 80.7 feet per second. In 4 seconds, your CMV will travel 4 × 80.7 = 323 feet. For that entire distance, your eyes will be watching your phone, not the road. Studies have shown that drivers take an average of 3.8 seconds to dial their cell phones. The length of a football playing field (i.e., not counting the two end zones) is 300 feet.

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 Rust around lug nuts may mean that they are loose.

Lug nuts must all be present and checked for tightness. Rust is a sign that the lug nut is loose.

Not quite. The answer is You can use the tachometer to tell you when to shift.

One way to determine when to upshift is with your tachometer. Before driving your vehicle, check the driver's manual to find out the recommended operating rpm range. As you're driving, keep your eye on your tachometer as your vehicle increases speed. Shift up when engine rpm gets to the top of the recommended range.

Not quite. The answer is With a tractor-trailer, the trailer can push the tractor sideways.

Rear wheel braking skids occur when the rear drive wheels lock. Because locked wheels have less traction than rolling wheels, the rear wheels usually slide sideways in an attempt to "catch up" with the front wheels. With a bus or straight truck, the vehicle will slide sideways in a "spin out." With vehicles towing trailers, a drive-wheel skid can let the trailer push the towing vehicle sideways, causing a sudden jackknife.

Not quite. The answer is 2 years.

An FMCSA-approved medical examiner's physical examination is valid for up to 24 months. However, you may have to undergo a medical examination more frequently if you have a medical condition that should be monitored more often, such as high blood pressure or diabetes mellitus.

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 a Selective Catalytic Reduction (SCR) system.

The exhaust gases of diesel engines include nitrogen oxides (NOx), a major contributor to air pollution and acid rain. To reduce most nitrogen oxide emissions, today's semi-trucks are equipped with a Selective Catalytic Reduction (SCR) system. Diesel exhaust fluid (DEF) is sprayed onto a special catalyst (a material that facilitates chemical reactions). DEF is a 32.5% solution of urea in water. As exhaust gases pass over the catalyst, DEF acts as a reductant, reacting with the NOx to form harmless nitrogen gas and water vapor, with a tiny amount of carbon dioxide as well. This system can reduce NOx emissions by up to 90%. The semi-truck's Diesel Particulate Filter (DPF) reduces particulates in the vehicle's emissions.

Not quite. The answer is Pitman arm

Component E is the Pitman arm. The Pitman arm connects the drag link to the output shaft of the steering box. As the output shaft rotates, the other end of the Pitman arm moves forward or backward, causing the drag link to move left or right, which turns the front wheels in that direction.

Not quite. The answer is Front axle hanger

A front (steering axle) suspension, like the one shown here, may also employ shock absorbers to further reduce up-and-down movements, producing a smoother ride. The axle is fastened to the suspension with a U-bolt.

Not quite. The answer is 15 degrees.

Drive-wheel braking skids occur when braking causes the drive wheels to lock. Because locked wheels have less traction than rolling wheels, the rear wheels usually slide sideways in an attempt to "catch up" with the front wheels. With combination vehicles, a drive-wheel skid can let the trailer push the tractor sideways, leading to a sudden jackknife. You can recover from the skid and get the trailer back into position – if you act fast before the trailer swings out about 15 degrees. (You have only a couple of seconds to react.) Past that point, it will be very difficult to prevent a jackknife.

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 Tractor and trailer

Either the tractor or the trailer can skid. If the drive wheels of the tractor lock, the tractor may skid, and the trailer may push the tractor sideways, causing a tractor jackknife. On the other hand, if the trailer wheels lock, the rear of the trailer may swing sideways, out of your lane. (This is more likely if the trailer is empty or lightly loaded.) This will result in a trailer jackknife.

Not quite. The answer is On a curve, it lets the outside wheels turn slower.

A differential uses a series of gears to accomplish several functions. First, it transfers torque from the drive shaft to the axle. Because the axle is at 90 degrees from the drive shaft, 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 In very hot weather, you should inspect your tires every two hours or every 100 miles.

In very hot weather, inspect your tires every two hours or every 100 miles. Each time, check the tire mountings and tire pressures. Tire air pressure increases with temperature, because air expands when its temperature rises. Do not let air out of the tire, or the pressure will be too low when the tire cools off. If a tire is too hot to touch, remain stopped until the tire cools off. Otherwise the tire may blow out or catch fire.

Not quite. The answer is No.

If one-fourth or more of the leaves in any leaf spring are broken or missing, the vehicle will be put out of service until the problem is repaired.

Not quite. The answer is front; left

On shifters that have both a range selector and a splitter, the range selector is usually on the front, and the splitter is usually on the left. As you hold the shifter, your index finger can move the range selector up and down, and your thumb can move the splitter forward or backward.

Not quite. The answer is on-time performance.

FMCSA's Compliance, Safety, Accountability (CSA) program includes the following seven Behavior Analysis and Safety Improvement Categories (BASICs): Unsafe driving, crash indicator, Hours of Service compliance, vehicle maintenance, controlled substances/alcohol, hazardous materials compliance, and driver fitness. Carriers who fail to correct unsafe behaviors can be taken off the road. Your performance as a truck driver is an important part of your company's record.

Source: "CSA: Compliance, Safety, Accountability," FMCSA, https://csa.fmcsa.dot.gov/

Not quite. The answer is Yes, because brakes can get out of adjustment when they are used a lot.

Check brake adjustment often. Brakes can get out of adjustment quickly, especially when they are hot. Out-of-adjustment brakes are the most common problem found in roadside inspections.