On a bus, it is acceptable to lock some roof hatches in a partially-opened position to provide fresh air, but this should not be made a regular practice. Remember that opening these hatches will slightly increase a bus's clearance.

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. You should be very careful when temperatures are below freezing and the road looks wet.

To test hydraulic brakes, you should pump the brake pedal three times, then apply firm pressure to the brake pedal and hold for five seconds. The pedal should not move. If it does, there may be a leak.

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

To reduce the risk of distraction, do not engage in complex or emotionally intense conversations while driving. Pre-programming radio stations before your trip and avoiding eating, drinking, or smoking while at the wheel can also help you avoid becoming distracted while driving. Remember that mental distractions that take your attention away from the task of driving can be just as dangerous as physical distractions.

If you are being tailgated, it is advisable to open up the space in front of your vehicle, making it easier for the tailgater to get around you. Speeding up may be counterproductive because the driver may continue to tailgate you at the higher speed, only increasing the danger.

When inspecting the engine compartment, you should check the oil level, coolant level, and windshield washer fluid level, among other things. In both cold and hot weather, it is important that the engine have enough coolant.

There are several reasons why driving at night is more difficult than driving during the day. It is more difficult for drivers to see hazards, the glare of headlights can affect drivers' vision, and there are more fatigued drivers on the road.

It is important for you to be aware of your surroundings at all times. To do this, regularly check your mirrors. You should make a particular point of checking your mirrors when merging, changing lanes, turning, and performing tight maneuvers.

When planning to turn left at an intersection, make sure you have reached the center of the intersection before beginning the turn. If you turn too soon, off-tracking may cause the left side of your vehicle to hit another vehicle.

Hydroplaning is an effect in which a vehicle's tires lose traction with the surface of the road and instead glide along a layer of water. There does not have to be a large amount of water on the road for this to occur. Hydroplaning can begin at speeds as low as 30 mph.

Black ice is a layer of ice that is thin and clear enough for the road to be visible through it. The surface will look like a wet road. Always be alert to black ice if the road looks wet when the temperature is below freezing.

On a downgrade, the force of gravity will cause a vehicle to speed up. Adjust your speed before approaching a hill to reduce overuse of your brakes.

Drivers with blocked vision may pose hazards to others on the road. Examples of such drivers include those who haven't scraped ice off of their windshields; those driving vehicles loaded with large items blocking the windows; and those who are driving rental trucks without being used to the limited rear visibility of a truck.

When backing a straight truck, you would turn the wheel in the direction you want to go. By contrast, when backing a vehicle with a trailer, you must turn the steering wheel in the direction opposite of where you want to go. Once your trailer starts to turn, you should turn the steering wheel the other way to follow the trailer.

You should shift your vehicle's transmission into a low gear before staring a downhill grade. Be prepared for gravity to increase your vehicle's speed when traveling downhill.

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.

If you are unsure of which method is appropriate to use to extinguish a fire, you should wait for firefighters to arrive and let them handle it. This is especially important when dealing with hazardous materials fires.

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.

Cargo must be properly secured to prevent it from moving in transit. Loose cargo can be dangerous to the driver operating the CMV, as well as to other road users.