ITD crews in the Montpelier, Preston and Malad areas will use a different method of winter maintenance on selected highways entering from Utah and Wyoming this winter.
Depending on the prevailing weather conditions and temperature, salt may be used exclusively or combined with small amounts of sanding material. Routes targeted for the new treatment include Interstate 15 from the Idaho/Utah line to Malad, U.S. 91 from the state line to Preston, U.S. 89 from the state line to Montpelier, and U.S. 30 from the Idaho/Wyoming state line to Montpelier.
ITD's use of salt on those segments will mirror the approach Utah uses to clear snow accumulations so motorists traveling from Utah will not experience a radical change when they reach the state line, explains Steve Gertonson, ITD District 5 maintenance engineer. Utah has experienced good success with salt-only applications for many years.
Recent tests in northern Idaho also proved effective in the treatment of highways that receive regular winter snowfalls.
Crews don't immediately begin snow removal from the highways in Utah. Instead, once the snow depths reach 3-5 inches, trucks apply salt to begin melting the accumulation; when snow turns to slush, plows push it from the highway. The remaining salt/water solution on the highway surface also helps prevent ice build-up and should eliminate conditions called "broken snow floor" where patches of packed snow remain after plowing.
Instead of placing a salt/sand mixture several times during a storm, the concept is to put an initial, heavier application of salt at the beginning of a storm, thus lowering the freezing point on the road surface and preventing accumulation, Gertonson explains.
The difference regular drivers on Idaho's experimental segments will notice is that snow removal will not begin immediately when a storm arrives. They should anticipate small accumulations before treatment and should drive accordingly, Gertonson says.
The experimental salt application and slush removal should result in personnel, equipment and fuel savings.
"We anticipate this test use of salt only will result in a number of important benefits," Gertonson says. "The most important result should be improved safety for motorists."
Increased use of salt also should make spring cleanups easier and less costly than the removal of more traditional sanding materials. It also should reduce the risk of windshield breakage from sand and gravel and improve the environment by adding fewer particulates into the air.
ITD crews will will continue to treat highways outside the trial segments as they have in the past.
Soil samples have been taken along each selected route to monitor chloride levels and help protect the environment, but Gertonson expects no adverse impact. The amount of straight salt applied to highways should be about the same as with repeated salt-sand applications.
Motorists who drive through an area that has been treated with salt only should wash their vehicles often to prevent salt accumulations and minimize corrosion.