Adjusting Speed - The faster your vehicle is going, the more distance it will take to turn, slow or stop. For example, stopping at 60 mph does not take twice the distance it takes at 30 mph as one might think, but over three times the distance. Driving safely means adjusting your speed for road and traffic conditions, how well you can see, and obeying speed limits.
Adjusting To Road Conditions - There are various road conditions where to be safe you must slow down. For example, you must slow down before a sharp curve, when the roadway is slippery, and when there is standing water on the road.
The only contact your vehicle has with the road is through the tires. How good a grip the tires have with the road depends on the type and condition of the tires and the type and condition of the road surface.
Many drivers do not pay enough attention to the condition of their tires or to the condition of the roadway. It is important that the tires be in good condition and have enough air in them. See the vehicle owner's manual for correct tire pressure.
You do not have as much traction on gravel or dirt roads as you do on concrete or asphalt roads. When driving on gravel or dirt, you must slow down. It will take you much longer to stop and it is much easier to skid when turning.
Curves - A vehicle can travel much faster in a straight line than it can in a curve. It is easy to go too fast in a curve. If you go too fast, then the tires will not be able to grip the road and the vehicle will skid. Always slow down before you enter the curve so you do not have to brake in the curve. Braking in a curve can cause the vehicle to skid.
Slippery roads - Slow down at the first sign of rain, snow or sleet. These all make the roadway slippery. When the road is slippery, the vehicle's tires do not grip as well as they do on a dry road. How slow should you go? On a wet road you should reduce your speed about 10 mph. On packed snow you should cut your speed in half. Use snow tires or chains when the road has snow on it. On ice, you must slow to a crawl. It is very dangerous to drive on ice.
If at all possible, do not drive when the roads are icy. In some areas where there is a lot of icy weather, special studded tires are allowed. Because these tires can cause road damage, they are not allowed in many areas or on certain roads, or during summer months. (See Prohibited Equipment.)
Some road surfaces are slippery at certain times or places. Here are some clues to help you spot slippery roads:
- On cold, wet days shady spots can be icy. These areas freeze first and dry out last.
- Overpasses and other types of bridges can have icy spots. The pavement on bridges can be icy even when other pavement is not. This is because bridges can be colder and more icy than other roadways.
- When the temperature is around the freezing point, ice can become wet. This makes it more slippery than at temperatures well below freezing.
- If it starts to rain on a hot day, pavement can be very slippery for the first few minutes. Heat causes the oil in the asphalt to come to the surface. The road is more slippery until the oil is washed off.
Water on the roadway - When it is raining or the road is wet, most tires have good traction up to about 35 mph. However as you go faster, your tires will start to ride up on the water, like water skis. This is called hydroplaning. In a heavy rain, your tires can lose all traction with the road at about 50 mph. Bald or badly worn tires will lose traction at much lower speeds. The best way to keep from hydroplaning is to slow down in the rain or when the road is wet.
If it feels like your tires have lost traction with the surface of the road you should:
- Ease your foot off the gas pedal.
- Keep the steering wheel straight. Only try to turn if it's an emergency. If you must turn, do it slowly, or you will cause your vehicle to skid.
- Do not try to stop or turn until your tires are gripping the road again.
If you must drive in slippery conditions, review Dealing with Skids in the Emergencies section at the back of this manual.
Adjusting To Traffic - Vehicles moving in the same direction at the same speed cannot hit one another. Crashes involving two or more vehicles often happen when drivers go faster or slower than other vehicles on the road.
Keep pace with traffic - If you are going faster than traffic, you will have to keep passing others. Each time you pass someone, there is a chance for a collision. The vehicle you are passing may change lanes suddenly, or on a two-lane road, an oncoming vehicle may appear suddenly. Slow down and keep pace with other traffic. Speeding does not save more than a few minutes an hour.
Going much slower than other vehicles can be just as bad as speeding. It tends to make vehicles bunch up behind you and causes the other traffic to pass you. If vehicles are piled up behind you, pull over when safe to do so and let them pass. You should either drive faster or consider using roads with slower speeds.
Entering into traffic - When you merge with traffic, try to enter at the same speed that traffic is moving. High-speed roadways generally have ramps to give you time to build up your speed. Use the ramp to reach the speed of other vehicles before you pull onto the road. Do not drive to the end of the ramp and stop or you will not have enough room to get up to the speed of traffic. Also, drivers behind you will not expect you to stop. If they are watching the traffic on the main road, you may be hit from the rear. If you have to wait for space to enter a roadway, slow down on the ramp so you have some room to speed up before you have to merge.
Leaving traffic - Keep up with the speed of traffic as long as you are on the main road. If the road you are traveling has exit ramps, do not slow down until you move onto the exit ramp. When you turn from a high speed, two-lane roadway, try not to slow down too early if you have traffic following you. Tap your brakes and reduce your speed quickly but safely.
Slow moving traffic - Some vehicles cannot travel very fast or have trouble keeping up with the speed of traffic. If you spot these vehicles early, you have time to change lanes or slow down safely. Slowing suddenly can cause a traffic accident.
- Watch for large trucks and small underpowered cars on steep grades or when they are entering traffic. They can lose speed on long or steep hills, and it takes longer for these vehicles to get up to speed when they enter traffic.
- Farm tractors, animal-drawn vehicles, and roadway maintenance vehicles usually go 25 mph or less. These vehicles should have a slow-moving vehicle decal (an orange triangle) on the back.
Trouble spots - Wherever people or traffic gather your room to maneuver is limited. You need to lower your speed to have time to react in a crowded space. Here are some of the places where you may need to slow down:
- Shopping centers, parking lots, and downtown areas - These are busy areas with vehicles and people stopping, starting and moving in different directions.
- Rush Hours - Rush hours often have heavy traffic and drivers that always seem to be in a hurry.
- Narrow bridges and tunnels - Vehicles approaching each other are closer together.
- Toll plazas - Vehicles are changing lanes and preparing to stop and then speeding-up again when leaving the plaza. The number of lanes could change both before and after the plaza.
- Schools, playgrounds, and residential streets - These areas often have children present. Always be alert for children crossing the street or running or riding into the street without looking.
- Railroad crossings - You need to make sure that there are no trains coming, and that you have room to cross. Some crossings are bumpy, so you need to slow down to safely cross. Do Not Block The Crossing.