Iowa CDL DMV Knowledge Test Class A 2

If a vehicle is equipped, an application pressure gauge shows how much air pressure is being applied to the brakes. This gauge can help a driver identify if their brakes are beginning to fade.

A skid caused by over-acceleration can be resolved simply by removing your foot from the accelerator. Skids of this nature happen most frequently on surfaces covered in snow or ice.

Most alcohol is removed from the body by the liver, which processes alcohol at a fixed rate. Despite popular belief, techniques like drinking black coffee or taking a cold shower will not accelerate this process. The only thing you can do to become sober after drinking is allow your body the time it needs to eliminate the alcohol from your system.

To ensure that you can see as well as possible, don't wear sunglasses when driving at night. If you wear eyeglasses, make sure they are clean and unscratched. Make sure you are rested and alert before driving at night.

When inspecting your vehicle, you should check all belts for tightness and excessive wear. You should learn how much "give" is appropriate for each belt.

As the temperature begins to rise and ice on the road begins to melt, the road surface will often become even more slippery. Water from the slight melting will sit on top of the ice, decreasing the available traction even more. Always decrease your speed and drive with caution when traveling on slippery surfaces.

You must take an air brakes knowledge test to become licensed to operate a vehicle that is equipped with air brakes, including an air over hydraulic braking system.

Dry bulk tanks require special care to be driven, both because they have high centers of gravity and because the weight of the load can shift in transit.

Aggressive driving is the act of operating a motor vehicle in a selfish, bold, or pushy manner and without regard for the rights or safety of other road users.

Cargo with a high center of gravity makes a vehicle more likely to tip over than cargo with a low center of gravity. For this reason, it is important that the weight of cargo be distributed as low as possible.

Distractions while driving can be physical (such as reaching for an object), mental (such as making conversation with a passenger), or both (such as holding a phone to send texts). Strategies to help you avoid distracted driving include pre-programming radio stations; planning out your route in advance; avoiding complex or emotionally taxing conversation while driving; adjusting your mirrors before setting out; and not eating, drinking, or smoking while behind the wheel.

In an air brake system, air tanks have drains to remove accumulations of water and compressor oil. Allowing water and oil to accumulate in the system could cause damage to the brakes.

Smoking, eating, or drinking are distracting activities and should be avoided while you are driving. Instead, plan ahead and allow yourself time to stop to eat when making a lengthy trip.

In the event of a vehicle fire, you should leave the road and stop in an open area. Do not pull into a service station as fuels at the service station could catch fire. Report the fire and your location to emergency services.

Over-length, over-width, and/or overweight loads may require special permits from the Department of Transportation.

If you remain in neutral for too long while switching gears, you may have difficulty putting the vehicle into the next gear. If this happens, do not try to force the gear shift. Instead, return to neutral, release the clutch, increase the engine speed to match the road speed, and try again.

When exiting your vehicle during the basic vehicle control skills test, you must face the vehicle and maintain three points of contact at all times. If your testing vehicle is a bus, you must maintain contact with the handrail. Exiting the vehicle incorrectly may result in automatic failure of the basic vehicle control skills test.

You should cover your cargo to protect people from the cargo if it spills, as well as to protect the cargo from the weather.

During the vehicle inspection test, you will be required to do a complete inspection of your vehicle. During this inspection, you must explain to the examiner what you are inspecting and why you are inspecting those items.

The adjustment of your mirrors should be checked prior to the start of all trips. Adjust your mirrors as needed.

Wheels or rims with welding repairs are never safe to use.

Brakes are designed to take a lot of heat, but drivers should not rely solely on the brakes to slow their vehicle. Brakes may fade and lose their ability to slow down the vehicle if they become too hot, so drivers should also rely on the engine braking effect.

If your vehicle has air brakes, the air compressor drive belt should be checked before each drive. Check the tightness of the belt and verify that it is in good condition.

When inspecting a vehicle that is equipped with power steering, check the hoses, pumps, and fluid level. In particular, you should look for leaks in the hoses.

Texting while driving is dangerous and is never permitted while operating a CMV.

Hydroplaning is most likely to occur when driving on wet roads with tire pressure that is too low and tire tread that is too worn. If there is enough water on the road, hydroplaning can occur at speeds as low as 30 mph.

Completing the steps of a vehicle inspection in the same order before every trip aids in learning what the proper steps are. Additionally, you be less likely to forget a step when going through the checklist in a prescribed order.

If your vehicle begins to hydroplane, do not apply the brakes. Instead, slow down by releasing the accelerator and pushing in the clutch. This will help you to regain traction.

If confronted by an aggressive driver, don't let yourself be provoked by their actions or angry gestures. Do not risk provoking the other driver by making eye contact. Get out of their way if you can do so safely.

While driving, you should watch your vehicle's gauges for signs of trouble. Be sure to inspect your gauges before beginning a trip to ensure that they are in proper working order.

Transporting cargo that is loaded with a high center of gravity increases the risk that the transporting vehicle will tip over. Cargo should be loaded with a safe weight distribution.

Never assume that the posted height on a bridge or other overhead object is correct. Even if it was accurate when posted, things may have changed that affect clearance, either permanently (such as a repaving of the road) or temporarily (such as packed snow on the road).

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.

The average driver has a reaction time between three-quarters of a second and one second. At 55 mph, this corresponds to a distance of 61 feet traveled.

A modulating control valve allows a driver to gradually apply spring brakes. In equipped vehicles, the valve is controlled by a lever located on the dashboard.