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

Control of a Vehicle

The following three systems help to control your
vehicle while driving — brakes, steering, and
accelerator. At times, as when driving on snow or
ice, it is easy to ask more of those control
systems than the tires and road can provide.
Meaning, you can lose control of your vehicle.
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See StabiliTrak System on page 337.
Adding non-dealer/non-retailer accessories can
affect your vehicle's performance. See Accessories
and Modifications on page 385.

Braking

See Brake System Warning Light on page 222.
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.
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.
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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 the 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. The brakes might not have time
to cool between hard stops. The brakes will
wear out much faster if you do a lot of heavy
braking. If you keep pace with the traffic and allow
realistic following distances, you will eliminate a
lot of unnecessary braking. That means better
braking and longer brake life.
If your vehicle's engine ever stops while you
are driving, brake normally but do not pump
the brakes. If you do, the pedal could get
harder to push down. If the engine stops,
you will still have some power brake assist.