Winter Road Maintenance Practices

What are ODOT winter maintenance practices?

ODOT winter maintenance practices include plowing, sanding, and applying winter anti-icing liquids. The combination of practices used at each site may vary to accommodate the different climate, traffic, and storm conditions encountered. ODOT's goal is to provide safe roadway. However, it is always up to the motorist to drive according to conditions.

ODOT maintenance practices include:

  • Plowing: Using snowplows and other equipment to remove snow and ice from bridges and roads.
  • Sanding: Applying material specified for each area (includes various sizes of gravel or cinders) on highways to improve vehicle traction.

Winter liquid products are used in several ways:

  • To melt snow and ice on the road surface(used as a deicer).
  • To help prevent snow and ice from sticking to the road surface (used as an anti-icer).
  • In conjunction with sand to help the sand stick to icy roads(used to pre-wet sand).

What winter anti-icing/deicing liquids are used by ODOT?

ODOT uses the following type of winter anti-icing/deicing liquid:

Magnesium chloride:

  • Contains a corrosion inhibitor to reduce impacts to vehicles.
  • Works well at cold temperatures.
  • Fairly inexpensive.

The anti-icing/deicing liquid used by ODOT is selected for the ability to meet the needs of Oregon’s various temperature, weather, and environmental conditions. ODOT may use other anti-icing/deicing liquid products as needed to increase efficiencies in winter maintenance operations.

Why does ODOT use winter anti-icing/deicing liquids?

ODOT uses winter anti-icing/deicing liquids as tools to improve safety, improve the efficiency of time spent plowing, and address environmental concerns resulting from other methods of snow removal. Other states that use winter anti-icing/deicing liquids have had reductions in wintertime motor vehicle crashes. Additionally, the anti-icing/deicing liquids can be cheaper than sanding and may reduce the amount of time spent plowing.

How do winter anti-icing/deicing liquids work?

Winter anti-icing/deicing liquids are applied to the road in order to lower the freezing temperature of water and to prevent ice and snow from forming a bond to the roadway surface. These products are used for:

  • Anti-icing: The product is applied to the road before a storm to reduce the buildup of snow and ice, to prevent the ice or snow from forming a bond to the roadway surface and to help in removal of the snow or ice after the storm.
  • De-icing: The product is applied to a layer of ice or snow that is on the road. This will assist in melting the ice or snow.
  • Pre-wetting: The product is mixed into sanding material. This makes the sanding material stick to the ice or snow, and helps to prevent traffic from blowing the sanding material off the road.

What vehicle maintenance is recommended when driving roads treated with anti-icer/deicer liquids?

It is recommended to wash vehicles regularly. Winter maintenance anti-icers/deicers won't crack windshields or chip paint like sand, but may leave a film on vehicles. Even though the magnesium chloride product contains a corrosion inhibitor, it still can cause corrosion. Regularly wash vehicles to remove anti-icer/deicer liquid, sanding and road dirt encountered during winter months.

To further protect vehicles it is critical to keep a safe following distance behind plows and sand and anti-icer/deicer applicator trucks. This will reduce vehicle exposure to anti-icers/deicers and falling sand and will reduce the potential for crashes.

Are ODOT practices safe for the environment?

ODOT has worked with several environmental regulatory agencies to ensure its winter maintenance program is not only cost effective, but environmentally friendly as well.

Efforts to protect the environment include:

  • Researching anti-icer/deicer types and application rates to ensure there are no significant impacts to streams or fish.
  • Using anti-icers/deicers instead of sanding material to reduce air pollution. Sanding materials can increase particulate (small particles) air pollution.
  • Anti-icer/deicer products used are on the Pacific Northwest Snowfighters Association Qualified Products List.
  • Maintaining strict standards for winter anti-icers/deicers and sand to ensure products are clean and free of pollutants.
  • Applying the least amount of anti-icer/deicer and sand necessary to maintain the driving surface.
  • Minimizing the use of anti-icers/deicers and sand near environmentally sensitive areas.
  • Updating winter maintenance practices and policies, as new technologies become readily available.

How does ODOT use salt?

There is growing evidence that low levels of road salt, used in combination with the snow-fighting tools we already use, may be able to improve highway safety and mobility with minimal impact to the environment. ODOT is conducting a five-year pilot project (2012-2017) on two highways in Oregon to test this.

The two test areas connect Oregon with other states that already use salt on the same highways.

  • U.S. 95, in the southeastern corner of Oregon, runs about 120 miles between Nevada and Idaho, which both use salt. ODOT is experimenting with using salt in limited situations on this highway except in an area near a city water supply.
  • Interstate 5 over the Siskiyou Pass connects Oregon with California, which already uses salt on the Interstate. ODOT is experimenting with using salt in limited situations on 11 miles of this highway.

Why doesn't ODOT just use sand?

The use of sand does not work well under every winter roadway condition. In many cases, winter anti-icer/deicer liquids work better than sand. The anti-icers/deicers have been shown to be very effective for melting or preventing black ice. Anti-icers perform well in some freezing rain or light snow conditions. In addition, anti-icers can keep snow from firmly sticking to the pavement, and can be applied ahead of the storm, so the road is ready for traffic. Anti-icers/deicers do have limitations and are not always the best tool for the conditions.

Sand is the best tool for improving traction on packed snow and in heavy snowfall conditions, but sand requires a lot of handling. It requires repeated applications because it is easily blown off the road by traffic. In some areas, sand has to be swept up and hauled away for disposal, all of which add substantial costs. Even though ODOT has strict standards limiting the size of sanding particles, sand can chip windshields, headlights, and paint.

Both sand and winter anti-icer/deicer liquids have drawbacks, but each has strengths that, under certain conditions, make each one valuable for improving safety. However, it is always up to the motorist to drive at speeds appropriate for the road and weather conditions.

ODOT Information Sources?

For questions regarding winter road maintenance practices, contact Scott Rattay, ODOT Maintenance & Operations Branch at (503) 986-4484.