Road Management & Engineering Journal
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MDSHA (Maryland State Highway Administration) Strategies for Winter Operations
(This article is reproduced, with permission, from the Winter 2000-2001 (Volume 17, Number 1) issue of
Tech Notes the newsletter of the Maryland Transportation Technology Transfer Center's Local
Technical Assistance Program at the University of Maryland in College Park, Maryland.)
All agencies have to develop their own winter maintenance programs and policies. The
Maryland State Highway Administration (MDSHA) recently summarized their strategies
with a few facts and figures. In addition to plowing snow, most programs include two
main strategies to handle ice:
- Anti-Icing proactive preventive winter maintenance strategy of
applying a liquid chemical to roads and bridges prior to the onset of precipitation
in order to prevent snow and ice from bonding to the pavement.
- Deicing -- traditional winter maintenance strategy of breaking the
snow/ice/pavement bond after it has occurred. It requires more material to break
the bond than to prevent it. SHA is expanding its anti-icing operations in an
attempt to lessen its overall salt usage.
MATERIALS FOR THE 2000-2001 WINTER SEASON
Of a variety of possible materials, SHA uses:
- Rock Salt (sodium chloride) is the principal winter material used by
SHA. It is effective down to 20 degrees Fahrenheit and at approximately $34
per ton, is relatively inexpensive.
- Salt Brine (liquid sodium chloride or liquefied salt) is a solution that can
be used as an anti-icer on bridge decks prior to the onset of storms, or as a
deicer on road surfaces during a storm. The material has a freeze point of -6
degrees Fahrenheit. Salt brine costs approximately 5 cents per gallon to
manufacture, after the initial purchase of a brine maker for $5,500. Salt brine
will be used at the brine making facilities and, in addition, will be distributed to
thirteen other maintenance shops in Southern Maryland and on the Eastern
- Magnesium Chloride (mag) is the principal liquid winter material used by
SHA. Mag is used in anti-icing and deicing operations just as salt brine is used.
The material has a freeze point of approximately -26 degrees Fahrenheit. SHA
evaluated the effectiveness and cost savings of using this material in conjunction
with salt versus using salt only. At 67 cents per gallon, magnesium chloride was
found to be the most effective in the colder regions of the state.
- Abrasives including sand, crushed stone, slag are used to increase
traction for motorists during storms. They have no snow melting capability. SHA
uses a limited amount of this material, concentrating its efforts on melting and
plowing snow and ice from the pavement.
- Calcium Chloride is a solid (flake) winter material used during extremely
cold winter storms.
- CMAK is a costly, non-chloride liquid chemical used in environmentally
sensitive or other selected areas for winter operations.
In addition to its fleet of salt spreading/snow plowing dump trucks, SHA uses:
- 5 salt brine machines: The shops with these machines produce brine
for themselves and for surrounding shops.
- 7 truck-mounted liquid applicator spray tanks: These units are used to
spray liquid chemicals on roads and bridges prior to precipitation to prevent
snow and ice from bonding to the pavement (anti-icing operations).
- 177 truck-mounted saddle tanks: This equipment is used to prewet salt
as the salt is spread on the highways. Prewetting salt helps it adhere to the
pavement (reducing waste), go into brine solution quicker (more effective) and
work at low temperatures.
- 6 fixed location overhead spray systems: These systems are used to
prewet salt on trucks that do not have saddle tanks. The systems increase the
effectiveness of salt.
- 1 automated bridge anti-icing system: This technology automatically
sprays a liquid chemical on the I-68 bridge over Street Road in Allegany County,
prior to the formation of frost or precipitation.
- 10 wing plows: A wing plow is an extra plow mounted on the right side
of a plow truck, allowing crews to clear more snow from road and shoulder.
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