WSDOT Perspective on Studded Tires
In 2001 the state’s Blue Ribbon Commission on Transportation recommended
that
studded tires be banned or a fee be assessed on the sale of studded tires.
Because public safety is the primary concern of the
Washington State Department of
Transportation (WSDOT), the department recommends motorists become aware
of the
hazards associated with studded tires and educated on alternatives.
Studded tires are only effective in improving traction on ice at or
near the freezing
temperature when ice is the most slippery. This condition is estimated
to occur less than
one percent of the time in Washington State. In other situations, such
as dry or wet
pavement, studded tires are less safe because stopping distances are
increased and
handling is compromised due to the metal studs. Drivers are trying to
start and stop on
metal rather than on rubber tire tread.
Studies show that studded tires offer no advantage on snow-covered roads.
This is
coupled with the fact that WSDOT is becoming more proactive in winter
maintenance,
keeping roads bare and preventing frost or black ice more frequently
through anti-icing
with chemical applications. Studded tires also give drivers a false sense
of security so
they tend to drive a bit more aggressively than they should. A five mile-per-hour
increase
in speed removes any effectiveness the tires may provide. Therefore,
many drivers are
making travel for them and their families less safe by using the studded
tires.
Studded tires create ruts in the pavement. Pavement ruts create problems
with vehicle
directional control and are hazardous in wet weather because of ponding
and
subsequent problems due to hydroplaning and reduced visibility with water
spray.
Studded tires also polish stones in cement aggregate, which makes the
surface more
slippery for all vehicles.
In recent years technological advances in tire construction led to the
development of
tires that are more effective than studded tires on ice and provide increased
traction in
snow and on wet or dry pavement. Additionally, many studless tires contain
compounds
that function like studs but don’t damage the pavement – the
tread may contain air
bubbles that grip like suction cups, or the tread may incorporate a siping
design, allowing
the tire to grip the pavement or ice better. Side-by-side comparisons
show studless tires
to have improved traction, handling, cornering, and braking compared
to studded tires.
Pavement damage is a costly problem associated with studded tires. The
estimated cost
for pavement repair on Washington State highways due to studded tires
is over $10
million annually. This is a cost borne by all taxpayers, not just the
users of studded tires.
For more detailed information related to studded tires and a variety
of links including
reports and facts on alternative tires, visit the WSDOT Winter Driving
Tips Web site at
www.wsdot.wa.gov/winter/. WSDOT hopes this information provides
enough
incentive to consider the use of alternative tires during the winter
months. They are safer
for you and your family, for other motorists, and will cost all taxpayers
less in the long
run.
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