The Wisconsin DOT contracts with all 72 county highway
departments in the state to maintain the state highway system.
(Interstates, federal and state numbered highways)
There are 113,000 miles of local streets and county and state highways in
Wisconsin including 11,612 miles (31,429 lane miles. One lane
mile equals a one mile roadway that is 12 feet wide) of state maintained highways.
The Milwaukee County Metro Area has 1,136 lane miles to plow. This figure
includes freeway lane miles, ramps and frontage roads. The
downtown area, however is maintained by the city of Milwaukee
and not the Milwaukee County Highway Department.
Wisconsin average snowfall ranges from about 40 inches in the
south to as much as 160 inches along the shores of Lake
On average, about 35 to 40 winter weather events hit Wisconsin
Blowing snow and fog that occur periodically can cause severe
visibility restrictions for drivers.
While only a couple large freezing rain events normally strike
the state each winter, the state experiences numerous freezing
drizzle and freezing fog events that cause roads to ice over.
Frost on bridge decks and pavements typically occurs in
October, November, and March.
There are over 1,500 county highway department employees that
are licensed to operate a snowplow.
Approximately 729 of them are permanently assigned to the state maintained highway
operators on the state system are required to hold a current
Commercial Drivers License (CDL).
snowplow drivers are not involved in snow and ice operations,
they work on priority maintenance projects including equipment
maintenance, crack sealing and pothole patching, maintaining
clear zones, maintaining drainage systems, emergency shoulder
repair, sign maintenance and repair, vegetation management, etc.
Snowplows typically travel at 25-35 mph, which in many
cases is significantly slower than the posted speeds.
driver's field of vision is also severely restricted.
It is illegal (State Statute 346.915) to follow a
snowplow closer than 200 feet upon any highway having a posted speed limit of more than 35 mph if the
snowplow is engaged in snow and ice removal.
It is legal to pass a snowplow but care should be
taken when attempting this maneuver because it's often
difficult to see past the snowplow because of the snow
cloud. Also the snowplow's wing blade can extend
up to 10 feet beyond the width of the truck. Many
snowplow wing blades are hit each season by vehicles attempting to
pass the snowplow.
Last winter (03-04) there were 59 crashes involving
snowplows and motor vehicles on the state maintained
highway system. One crash involved a fatality.
Twenty-eight of the 59 crashes last winter involved a snowplow
being rear ended or hit while being passed by a vehicle
that was traveling in the same direction as the
In the past 21 years (1984-2004), there were 17 snowplows involved in fatal crashes in Wisconsin.
snow removal program divides the state maintained highways
into 5 categories based on the highway's traffic
volumes, use, and configuration. The goal for each category of
roadway is to achieve "passable roadways" during a
Passable roadways are defined as roadways that are free of
drifts, snow ridges, and as much ice and snow pack as is
practical and can be traveled at reasonable speeds. A reasonable
speed is one in which a vehicle can travel without losing
Category 1 highways receive more attention and resources than
other highway categories thus it will take less time to achieve bare/wet
pavement and ultimately bare/dry pavement on these
highways. Category 1 highways
typically carry more than 75,000 vehicles per day while category
5 highways have less than 5,000 vehicles per day.
removal times can vary depending on moisture content of the snow
and weather conditions. Heavy, wet snow followed by a cold snap
could require more time to clear than dry snow.
The county highway departments who maintain the state highway
system are not
liable for injuries caused by ice or snow accumulation on the roadway unless it has been there for
more than 3 weeks (State Statute 81.15). That being stated, it typically takes only a
day or two, even in the worst storms, to remove the majority of
the ice and snow from the pavement.
Snow Removal Techniques
This winter, 64 of the 72 counties in Wisconsin are using a
technique called anti-icing, which can save time and
money by reducing the effort and materials needed to
remove snow and ice.
prevents the formation of frost and the bonding of snow and
ice to the pavement.
Anti-icing agents, which are primarily liquids, are applied before
or early in a snow storm.
removal techniques include pre-wetting and de-icing.
Pre-wetting is the addition of calcium chloride, magnesium chloride, salt brine or other
liquid agents to
salt and sand. This helps the mixture stick to
the road instead of blowing off to the shoulder, which
reduces the amount of material needed. It also helps the
salt start working more quickly. (Currently only a handful
of counties do not pre-wet their salt.)
uses chemical or mechanical means to break the bond that has
formed between ice and the pavement.
WisDOT uses an advanced Road Weather Information System (RWIS)
and customized forecasts to track weather and pavement
conditions. The RWIS has 61 sites across the state that
include weather sensors and sensors embedded in the roadway.
data helps determine when to mobilize staff, time
deicing/anti-icing agent applications, and choose the best
agent to use.
an average of 385,000 tons of salt and 20,000 tons of sand per
season statewide. The total storage capacity of salt for use on
state maintained highways is about 410,000 tons.
The Milwaukee area uses an average of 93,000 tons of salt per season.
and type of snow or ice storms has a more significant impact on
expenditures than snowfall totals since staff and equipment may
be mobilized even if only 0.10 inches of snow or freezing rain falls.
Weekend and evening storms are also more costly than weekday
storms because the crews work on overtime.
Salting is cost effective down to a
pavement temperature of only about 15-20 degrees. It takes about 13
times more salt to melt ice when the pavement temperature is 0°F
than when it is 30°F.
Sand is sometimes used to improve traction on ice. However, it
only takes about 30 vehicles traveling at highway speeds to blow
the sand off the roadway.
County highway departments have 729 trucks available for snow
removal on the state maintained highway system.
equipped trucks weigh 12-25 times more than the average car (a
typical single axle maintenance truck weighs 23,000 pounds and a
tandem tri-axle truck weighs 50,000 pounds).