Stopping Distance
An average vehicle traveling at 55 mph takes approximately 400 feet to come to a complete stop, while a large truck traveling at the same speed can take almost 800 feet to stop. Note that these stopping distances apply under perfect road conditions (and that's assuming the tires and brakes are in tip-top shape). You need to increase stopping distance in less-than-perfect driving conditions (for example, if the road is wet).
How important is it to give yourself enough stopping space? Well, imagine for a moment that black-and-green wall in the cartoon below is your vehicle….or worse…a small child crossing the street.
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Preview Speed
The faster you drive, the less control you have over your vehicle. If you can only see 100 feet ahead because of weather conditions, do not drive at a speed that requires 200 feet to stop. You must either adjust your speed and drive according to the environmental conditions or find a safe place to wait out the bad weather.
Preview Slippery Roads
Preview
A road that is normally safe can become dangerous when wet. Slow down when there is water, snow, or ice on the road in order to avoid rear-ending another vehicle.
Some road surfaces are more slippery than others. Here are some guidelines for adjusting speeds in certain conditions:
Wet roads: reduce speed 5 to 10 mph.
Packed snow: cut speed in half.
Ice: slow to a crawl.
In heavy rain, your tires can lose all contact with the road at a speed of about 55 mph. When this happens, your vehicle will hydroplane. "Hydroplaning" occurs when a thin film of water builds up between the tires and pavement and makes steering and braking practically impossible. If your vehicle starts to hydroplane, do not panic and apply the brakes. Instead, slow down gradually.
To help avoid a skid on slippery surfaces, do the following:
Drive more slowly and keep a greater distance behind the vehicle ahead.
Slow down as you approach curves and intersections.
Avoid fast turns.
Avoid quick stops. "Pump" the brakes to slow or stop (unless you have anti-lock brakes, which should not be pumped).
Shift to low gear before going down a steep hill.
Avoid especially slippery areas, such as ice patches, wet leaves, oil, or deep puddles.
If the brakes get wet - for example, from driving through a puddle - and your braking ability is reduced, dry your brakes by lightly pressing the gas pedal and brake pedal at the same time so that the vehicle drives against the pressure of the brakes. Do this only until the brakes begin working.