Gypsum Express News

Maintaining a SAFE Following Distance Prevents Collisions
April 10, 2008

The American Trucking Associations (ATA) says the most
frequent complaint against truck drivers is “tailgating.”
Tailgating is also a frequent cause of crashes, especially
rear-end collisions, because tailgating significantly reduces
the space cushion with the vehicle ahead. Rear-end collisions
represent 23 percent of all collisions. In greater than 90 percent
of rear-end collisions, driver inattention/distraction and/or
following too closely are contributing factors. Most rear-end
collisions are preventable if motorists would simply slow down
and increase the space between their vehicle and the vehicle
ahead to a safe distance based upon the road, traffic and weather
conditions present.

BE AWARE OF YOUR STOPPING DISTANCE.
Many drivers do not always consider that stopping
distance is directly proportional to several factors. The
National Safety Council’s (NSC’s) Defensive Driving
Course Guide for the Professional Truck Driver explains
that a vehicle’s stopping distance depends on the
following factors:

1. The vehicle you are driving (type, condition, weight
load, tires, brakes and speed). For instance, a car
traveling on a dry road at 55 mph takes almost 346 feet
to stop, while a truck traveling on the same road at 55
mph takes almost 477 feet to stop. Speed increases the
distance a vehicle travels while the driver reacts to a
dangerous situation and extends the distance necessary
for the vehicle to stop. Whenever you double your speed,
it takes approximately four times as much distance to stop
and your vehicle will have four times the destructive
power if it crashes.

2. The driving conditions, such as road type, road surface
and weather. Your stopping distance will vary depending on whether
you are driving on a level, inclining or declining section of
roadway; on a paved, gravel, dirt or muddy road surface; or on a
dry, wet or icy road.

3. The driver’s perception distance, which is the number
of feet your vehicle travels from the time an event occurs,
such as when the brake lights ahead light up, until the
driver spots it and recognizes the hazard. The average
perception time for a driver in good physical and mental
condition who is focused on driving is approximately
1.75 seconds – plenty of time for the traffic conditions
to change right in front of you.

4. The driver’s reaction distance, which is the number
of feet the vehicle travels from the time the driver
recognizes the hazard and gets their foot over the
brake. Average reaction time for a driver in good
physical and mental condition is ¾ of a second and
is equal in feet to the first digit of your speedometer
reading added to your total speed. For example:

20 mph = 22 feet reaction distance
40 mph = 44 feet reaction distance
50 mph = 55 feet reaction distance
55 mph = 60 feet reaction distance
60 mph = 66 feet reaction distance

5. The vehicle’s braking distance, which is the number
of feet the vehicle travels from the time the driver
applies the brake until the vehicle stops. Unlike
four-wheel vehicle drivers, truck drivers must
add air-brake lag distance to their total braking
distance. Air-brake lag takes approximately
½ second of additional time. This distance increases
with the speed of the vehicle. The NSC says brake
test studies show that, in some cases, braking distance
can vary by 10 percent to 20 percent. To allow for this
variance, always leave an extra margin of safety.
STOPPING DISTANCE =
PERCEPTION DISTANCE + REACTION DISTANCE
+ BRAKING DISTANCE

KEEP A SAFE FOLLOWING DISTANCE AT ALL TIMES
Following distance is the distance between the front
bumper of your vehicle and the rear bumper of the
vehicle ahead. The NSC recommends that truck drivers
keep at least a six-second following distance when
driving in ideal conditions. As your speed increases
and/or as driving conditions change, add one or more
additional seconds. To determine a safe following
distance for your truck, follow these NSC guidelines:

• For speeds below 40 miles per hour, use one second
for each 10 feet of your vehicle length. It is wise to
round any half second that results from this formula to
the next higher whole second. (i.e., 60-foot vehicle = 6
seconds; 65-foot vehicle = 7 seconds rounded; 70-foot
vehicle = 7 seconds)

• For speeds above 40 miles per hour, use the above
formula plus ADD one more second to your following
distance.

• For special vehicles, such as a trailer hauling autos
or other over-length cargo, ADD additional seconds
based upon the total vehicle length, including the cargo
overhang.

• ADD one second for each type of adverse condition
that exists, such as snow, rain, fog, ice, darkness, gravel
road, roadway work zone, driver fatigue, etc.

• ADD one second for every two hours of driving time.

• ADD a tailgater’s following distance to your following
distance. This will give you and the tailgater more time
and distance to slow down. Most importantly, it gives
you more time to slow your vehicle at a rate of speed
that will keep you from being
rear-ended by the driver who is
tailgating you.

FOLLOW THESE ADDITIONAL SAFETY TIPS
The NSC, ATA and Baldwin &
Lyons, Inc. recommend the following
additional ways to make sure you are
maintaining a safe following distance:
• To determine correct following
distance, watch the vehicle ahead of
you pass a definite mark (such as a
pole, sign or other marker) and begin
counting to yourself “one-thousand
and one, one-thousand and two, onethousand
and three, one-thousand
and four, one-thousand and five,
one-thousand and six.” If the front
bumper of your vehicle reaches the
mark before you finish counting,
you are following too closely.
Momentarily slow down and check
your following distance again.

• Increase following distance and
decrease speed under adverse
road or weather conditions.
Decrease your speed and increase
your following distance when
roads are slippery due to rain,
snow, ice, loose dirt, mud, etc.
These conditions increase stopping
distances 3 to 12 times. As a
professional driver, you should
drive no faster than conditions
will permit in order to come to a
controlled stop and avoid a collision.

• Slow down in fog! Fog is often
unexpected, and visibility can
deteriorate rapidly. Watch for
foggy conditions and be ready to
reduce your speed and increase your
following distance immediately
when encountering fog on the
roadway. Fog can create a deadly
optical illusion and cloud your
judgment. The fog can be thicker
than you realize and cause other
vehicles, including the one ahead of
you, to be more difficult to see until
it is too late to avoid a collision.
The fog may also be “covering up”
a collision in front of you, which
would prevent you from having
adequate time and space to properly
react and stop.

• Be extra cautious on two-lane
roads. On two-lane roads, always
follow at a distance that will permit
a faster driver to pass and return to
the right lane easily.

• When passing another vehicle,
change lanes at the two-second
distance. If you cannot safely
complete the pass, drop back
and maintain a safe following
distance while you wait for another
opportunity. Until then, determine
if the pass is really necessary.

• In stop-and-go traffic, scan
ahead for vehicles making quick
stops or lane changes and continue
to maintain a safe following distance.
When the safe following distance
is taken away, regain that space
by momentarily slowing down.
Covering your brake pedal with your
foot will save your reaction time.

• Always watch traffic ahead.
Traffic can slow down or stop
suddenly on any road, at any time.
If you see brake lights ahead, act
immediately to increase your
following distance and adjust
your speed according to the
conditions so you can make a safe,
controlled stop.

• Reduce speed appropriately
before entering a curve or ramp.
Negotiate curves at a reduced speed
consistent with the sharpness of
the curve, available sight distance,
prevailing road and traffic conditions
and the stability of your load. Enter
the curve or ramp 10 mph below the
posted advisory speed. Advisory
speeds posted on most curve and
ramp signs are for passenger vehicles
and may not give the professional
truck driver an accurate idea of how
fast he/she can take the curve safely
and come to a stop if necessary.
Some ramps and curves have a
separate advisory speed for trucks.
That should be your guideline for
determining a safe speed.

• Stay alert and pay attention. Get
adequate sleep before your trip.
Fatigue and/or drowsy driving
will prevent you from accurately
judging your following distance and
noticing and reacting to warning
signs, slowed or stopped traffic, and
unexpected and sudden maneuvers
by other motorists.

• Always keep your total focus
on your driving. Professional
drivers always keep their eyes
on the road around them, never
diverting attention from the primary
obligation of controlling the vehicle
and protecting the drivers around
them. In-cab distractions, such
as using a cell phone, satellite
communication system, etc., will
lead to hazardous consequences.
Do not let in-cab distractions divert
your attention from the task of
driving. Do not let yourself become
complacent by reaching into a
cooler, pouring coffee, reading a
map, adjusting the radio, talking
on a cell phone, or using a satellite
communication system. These types
of activities can distract you long
enough that you may fail to maintain
a safe following distance, fail to
notice and avoid hazards or traffic
in front of you, and/or be unable to
react appropriately. If you only look
down for a second and then look
back up and find traffic has come to
a complete stop right in front of you,
then you were following too closely
and were not sufficiently observant
of the conditions in front of and
around you.

• Be patient, cautious and
courteous at all times. Frustration
and inattention can easily lead to
crashes. A split second burst of
aggressive driving in heavy traffic
or in a cramped construction zone
is just not worth the often tragic
consequences. Never respond to
“road ragers.” Instead, give them
plenty of space to get out of your
safety zone.