GMC 1995 Safari Owner's Manual page 141

Braking
Braking action involves perception time and reaction time.
First, you have to decide to push on the brake pedal. That's perception time.
Then you have to bring up your foot and do it. That's reaction time.
Average reaction time is about 314 of a second. But that's 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 314 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's pavement or gravel); the condition of the road (wet, dry,
icy); tire tread; and the condition of your brakes.
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. 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 engine ever stops while you're driving, brake normally but don't
pump your brakes. If you do, the pedal may get harder to push down. If
your engine stops, you will still have some power brake assist. But you will
use it when you brake. Once the power assist is used up, it may take longer
to stop and the brake pedal will be harder to push.