A driver needs to be constantly aware of changing road conditions
and adjust her driving as necessary to avoid having the vehicle go
into a skid. A skid happens whenever the tires lose their grip on
the road. This is caused in one of four ways:
- Braking too hard and locking up the wheels. Skids also can occur when using a vehicle’s speed-retarder on a slippery road surface.
- Turning the wheels too sharply.
- Supplying too much power to the drive wheels, causing them to spin.
- Driving too fast for road conditions (the most common cause).
Road conditions affecting traction
The type of road surface and its condition affect the ability of the vehicle to maintain traction:
- Asphalt is more slippery than concrete when it first rains, because it contains petroleum.
- Concrete tends to be less slippery than asphalt in rain and light snow.
- Ice forms more slowly on a gravel road than on asphalt or concrete.
- Dry sand reduces traction and can cause the vehicle to slide or skid.
- Wet leaves and standing water on the road surface can severely reduce traction.
You also need to watch the road contours while driving in slippery conditions: a high crown or crest, the banking on the road, curves in the road, soft shoulders or road edges, and potholes or frost heaves. The grade (steepness) of the road makes every slippery situation worse. This is true whether you are driving up a hill or down a hill.
Driving under slippery conditions
Going up a grade in slippery conditions:
- Downshift before you get to the grade.
- Climb the entire grade in the same gear. Having to downshift will cause you to lose traction. Use a low gear.
- Keep moving at a slow and steady pace. Maintain your momentum.
- Make sure you have adequate snow tires or chains.
Going down a grade in slippery conditions:
- Slow down as you approach the grade.
- Downshift before you start down the grade.
- Brake carefully, using the appropriate method for the kind of brakes you have (ABS or non-ABS).
Recovering from a skid
If your vehicle starts to skid, the following techniques should help you regain control:
- To correct a rear-wheel skid:
- Stop braking - This will let the rear wheels roll again, and keep the rear wheels from sliding any further. If on ice, push in the clutch on a standard-shift equipped vehicle to let the wheels turn freely.
- Steer quickly - When a vehicle begins to slide sideways, quickly steer in the direction you want the vehicle to go. As a vehicle turns back on course, be ready, as it has a tendency to keep right on turning. Unless you turn the steering wheel quickly the other way, you may find yourself skidding in the opposite direction.
- To correct a front-wheel skid:
- Driving too fast for conditions causes most front-wheel skids. Other causes are lack of tread on the front tires and not enough weight on the front axle. In a front-wheel skid, the front end tends to go in a straight line, regardless of how much you turn the steering wheel. On a very slippery surface, you may not be able to steer around a curve or turn. When a front-wheel skid occurs, the only way to stop the skid is to let the vehicle slow down.
COPYRIGHT ©2002, ISO Services, Inc.
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