Figure 7-27.—Reflective triangle placement: one way or
divided highway.
rule of thumb used for measuring how much distance
you should maintain from the vehicle in front of you is
at least 1 second for each 10 feet of vehicle length at
speeds below 40 mph. At greater speeds, you must add
1 second for safety; for example, if you are operating a
40-foot vehicle, you should allow at least 4 seconds
between you and the vehicle ahead. In a 60-foot tractor-
trailer, you need 6 seconds. For over 40 mph, you need
5 seconds for a 40-foot vehicle and 7 seconds for a
60-foot tractor and trailer.
To measure distances, wait until the vehicle ahead
passes a shadow on the road, a pavement marking, or
some clear landmark. Then count off the seconds as “one
thousand-and-one, one thousand-and-two” and so forth,
until your vehicle reaches the same spot. Compare your
count with the rule of 1 second for every 10 feet of
length. If you are operating a 40-foot truck and only
counted up to 2 seconds, you are too close.
LOADING AND SECURING CARGO
As a tractor-trailer operator, you must have an
understanding of the basic procedures and safety rules
used when transporting construction supplies and
equipment. Improper loading of any load can be a
danger to yourself and others around you, cause damage
to the tractor-trailer, affect the steering of the tractor, and
so forth. The operator, whether or not you loaded and
secured the load yourself, is responsible to inspect the
load, to recognize overloads and poorly balanced
weight, and to ensure that the load is properly tied,
strapped, or chained down, and covered (if required).
NOTE: It takes less time to tie down a load than it
takes to report the reason a load fell off a trailer.
Vehicle Weight Definitions
The operator is responsible for knowing how much
weight is loaded on the tractor-trailer and knowing the
total weight of both the unit and cargo. The terms used
for vehicle weight is as follows:
Payload allowance or payload is the maximum
weight of material that can be transported.
Gross vehicle weight (GVW) is the total weight of
a single vehicle plus its load.
Gross combination weight (GCW) is the total
weight of a powered unit including the trailer(s) and
cargo.
Gross vehicle weight rating (GVWR) is the
maximum GVW specified by the manufacturer for a
single vehicle, including the load.
Gross combination weight rating (GCWR)is the
maximum GCW specified by the manufacturer for a
specific combination of vehicles, including the load.
Curb weight is the total weight of the empty truck
with the fuel tank, cooling system, and crankcase filled.
Additionally, it also includes the weight of tools, spare
tire, and all other equipment specified as standard. How-
ever, this weight does not include the weight of the
payload and operator.
Axle weight is the weight transmitted to the ground
by one axle or one set of axles.
Tire load is the maximum safe weight a tire can
carry at a specified pressure. This rating is stated on the
side of each tire.
Suspension systems have a manufacturer’s weight
capacity rating.
Coupling device capacity are rated for the
maximum weight they can pull and/or carry.
Operating Conditions
The maximum payload of a truck is determined by
subtracting the curb weight and weight of the driver
(175 pounds) from the manufacturer’s gross vehicle
weight rating. The maximum gross vehicle weight
rating for a specified operating condition applies only
when the tires and equipment on the truck are according
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