South Dakota CDL DMV Knowledge Test Class A 1

Some older vehicles have front brake limiting valves with "normal" and "slippery" settings. Setting a brake limiting valve to "slippery" reduces the vehicle's stopping power, so a driver should make sure the valve is in its "normal" position. Front wheel braking has proven to be effective in all driving conditions.

To reduce the chances of becoming fatigued on a long trip, a driver should stop for a break at least once every two hours or 100 miles driven.

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.

Vehicles with air brakes are required to be equipped with a low pressure warning device. A wig wag is a type of low air pressure warning device. This device drops a mechanical arm into the driver's view if the pressure in the tanks drops to a level between 55 and 75 psi.

Always slow down before entering a foggy area. Use low beam headlights, avoid passing others, and avoid stopping on the side of the roadway. It is safest to completely avoid driving under foggy conditions, if possible.

Regrooved, recapped, or retreaded tires are prohibited on the front wheels of a bus.

Cargo should be inspected before beginning a trip, within the first 50 miles of the trip, and every three hours or 150 miles traveled thereafter. The driver of a truck transporting cargo is responsible for the cargo being safely secured throughout the trip.

Backing up is always dangerous because it is impossible to see everything that is behind you. Only drive in reverse if it is absolutely necessary.

If your brakes fail on a downgrade, your best option is to use an escape ramp. If no escape ramp is available, it is a good idea to look for a different escape route, such as a side road or open field.

A steering wheel should have no more than 10 degrees of play. This is equal to about two inches of movement at the rim of a 20-inch wheel. If there is more play than this, it may be difficult to steer.

You should finish each exercise with your vehicle in the exact position described by the examiner. You can be penalized for failing to complete an exercise exactly in the manner described by the examiner, potentially resulting in failure of the basic control skills test.

An alcohol evaporator can help prevent ice from building up in an air brake system. In cold weather, the evaporator should be checked and refilled every day.

Retarders are mechanisms in some vehicles that help slow a vehicle and reduce the need for braking. However, using a retarder may cause wheels to skid when they have poor traction. Turn off retarders when traveling under wet, snowy, or icy conditions.

Before driving, you should always verify that your service brakes are in good working order. Testing the brakes before a trip allows you to locate any problems before you need to brake while on the road.

During a trip, you should regularly make checks to ensure that your vehicle is operating properly. Check the instrument panel and gauges; look at your mirrors; and examine the tires, cargo, and lights. Use all of your senses and be alert for anything that could be an early indication of trouble.

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.

When approaching a vehicle for an inspection, you should check underneath it for fresh oil, coolant, grease, or fuel leaked onto the pavement. Any of these could indicate a problem that will need to be repaired before the vehicle is driven.

Any vehicle with air brakes must be equipped with a low air pressure warning signal.

When examining the engine compartment during a pre-trip inspection, you should check the engine oil level, the radiator coolant level, and the condition of the hoses.

Large vehicles often have curved, convex mirrors, sometimes referred to as "fisheye," "spot," or "bug-eye" mirrors. These mirrors provide a wider view than flat mirrors. However, they also make objects seem smaller and farther away than they actually are.

You should accelerate very gradually when driving under conditions that create poor traction.

Brakes can get out of adjustment quickly, especially if they are used to the point of overheating. Brake adjustment should be checked frequently.

All commercial motor vehicles are required to be equipped with the proper emergency equipment. This may include spare electrical fuses; three red reflective triangles, six fuses, or three liquid burning flares; and at least one properly charged and rated fire extinguisher.

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 control skills test.

There are two indicators that determine when you need to shift into a higher gear. One indicator is the engine speed (rpm). You should read your vehicle's manual to learn its rpm range and shift up when you reach the top of that range. The other indicator is road speed (mph). You should learn which speeds each gear can accommodate, then keep an eye on the speedometer and shift up as needed.

Black ice is a thin layer of ice that is clear enough for the road surface to be seen through it. A road covered in black ice may look like it is merely wet.

While driving, you should continually scan the road ahead to spot potential hazards well in advance. Make emergency plans for how to deal with the hazards in the event that they become dangerous.

To avoid becoming fatigued on a long trip, you should take a break after every 100 miles or two hours of driving. Driving through the night, or during any other time when you would normally be asleep, raises the danger of fatigue.

An alcohol evaporator can help prevent ice from building up in an air brake system. In cold weather, the evaporator should be checked and refilled every day.

If you stay in neutral for too long while double clutching and have difficulty switching your vehicle into the next gear, don't force it. Return to neutral, release the clutch, increase the engine speed to match road speed, and try again.

You should always slow down to a safe speed and shift into a lower gear before entering a curve.

While driving, regular mirror checks are essential to remaining aware of the traffic around you. Mirrors are also essential to helping you spot possible problems on your own vehicle.

When inspecting your vehicle, you should check the wiper blades for damage, stiff rubber, and proper securement. Clean the blades if they are dirty.

After an engine is started, the coolant temperature should begin a gradual rise toward the normal operating range.

If a pre-trip inspection reveals anything unsafe about your vehicle, you must get it repaired. It is illegal to operate an unsafe vehicle.