Commercial Driver Handbook ( PDF ) - California Department of ...

• Adjust turning and braking to conditions.
Make turns as carefully as possible. Do not
brake any harder than necessary and do not use
the engine brake or speed retarder. (They can
cause the driving wheels to skid on slippery
surfaces.)
• Adjust speed to conditions. Do not pass
slower vehicles unless necessary. Go slowly
and watch far enough ahead to keep a steady
speed. Avoid having to slow down and speed
up. Take curves at slower speeds and do not
brake while in curves. Be aware that as the
temperature rises to the point where ice begins
to melt, the road becomes even more slippery
and you must slow down even more.
• Adjust space to conditions. Do not drive
alongside other vehicles. Keep a greater following
distance. When you see a traffic jam
ahead, slow down or stop and wait for it to
clear. Try to anticipate stops early and slow
down gradually.
Wet brakes. When driving in heavy rain or deep
standing water, your brakes will get wet. Water on
the brakes can cause the brakes to be weak, apply
unevenly, or grab. This can cause lack of braking
power, wheel lockups, pulling to one side or the
other, and a jackknife if you pull a trailer.
Avoid driving through deep puddles or flowing
water, if possible. If you cannot, you should:
• Slow down.
• Place transmission in a low gear.
• Gently put on the brakes. This presses linings
against brake drums or discs and keeps mud,
silt, and water from getting in.
• Increase engine rpm and cross the water while
keeping light pressure on the brakes.
• When out of the water, maintain light pressure
on the brakes for a short distance to heat them
up and dry them out.
CAUTION: Brake drums and linings can
overheat if you do this for too long.
• Make a test stop when safe to do so. Check
your mirrors to be sure no one is following, then
apply the brakes to be sure they are working.
If not, dry out further as described above.
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DRIVIng In VeRy hOt WeAtheR
During the pre-trip inspection, pay special attention
to the following items:
vehiCle CheCks
Tires. Check the tire mounting and air pressure.
Inspect the tires for overheating and tread separation
every two hours or 100 miles when driving
in very hot weather. Air pressure increases with
temperature. Do not let air out or the pressure will
be too low when the tires cool off. If a tire is too
hot to touch, remain stopped until the tire cools
off. Otherwise, the tire may blow out or catch fire.
Pay special attention to recapped or retreaded tires.
Under high temperatures, the tread may separate
from the body of the tire.
Engine oil. The engine oil helps keep the engine
cool, as well as lubricating it. Make sure there is
enough engine oil. If you have an oil temperature
gauge, make sure the temperature is within the
proper range while you are driving.
Engine coolant. Before starting out, be sure the
engine cooling system has enough water and
antifreeze according to the engine manufacturer’s
directions. Antifreeze helps the engine under hot
conditions, as well as cold conditions. When driving
in hot weather, check the water temperature
or coolant temperature gauge more frequently.
Make sure it remains in the normal range. If the
gauge goes above the highest safe temperature,
there may be something wrong that could lead to
engine failure and possibly fire. Stop driving as
soon as safely possible.
Some vehicles have sight glasses, see-through
coolant overflow containers, or coolant recovery
containers which permit checking coolant level
while the engine is hot. If the container is not part
of the pressurized system, the cap can be safely
removed and coolant added even when the engine
is at operating temperature. Never remove the
radiator cap or any part of the pressurized
system until the system has cooled. Steam and
boiling water can spray under pressure and cause
severe burns.