Control Of A Vehicle; Braking - GMC 2007 Yukon XL Owner's Manual

Control of a Vehicle

You have three systems that make your vehicle
go where you want it to go. They are the brakes,
the steering, and the accelerator. All three
systems have to do their work at the places where
the tires meet the road.
Sometimes, as when you are driving on snow or
ice, it is easy to ask more of those control systems
than the tires and road can provide. That means
you can lose control of your vehicle. See
®
StabiliTrak System on page 348.
Adding non-GM accessories can affect your
vehicle's performance. See Accessories and
Modifications on page 426.

Braking

See Brake System Warning Light on page 232.
Braking action involves perception time and
reaction time.
First, you have to decide to push on the brake
pedal. That is perception time. Then you have to
bring up your foot and do it. That is reaction time.
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Average reaction time is about three-fourths of a
second. But that is only an average. It might
be less with one driver and as long as two or
three seconds or more with another. Age, physical
condition, alertness, coordination, and eyesight
all play a part. So do alcohol, drugs, and
frustration. But even in three-fourths of a second,
a vehicle moving at 60 mph (100 km/h) travels
66 feet (20 m). That could be a lot of distance in an
emergency, so keeping enough space between
your vehicle and others is important.
And, of course, actual stopping distances vary
greatly with the surface of the road, whether it is
pavement or gravel; the condition of the road,
whether it is wet, dry, or icy; tire tread; the
condition of your brakes; the weight of the vehicle;
and the amount of brake force applied.
Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by
heavy braking — rather than keeping pace with
traffic. This is a mistake. Your brakes may
not have time to cool between hard stops. Your
brakes will wear out much faster if you do a lot of
heavy braking.