Changing winter driving habits could reduce use, ill effects of road salt

To keep roadways safe in snowy, winter conditions, the reliance on salt differs widely from one Wisconsin county to another. This creates challenges for state officials trying to reduce overall usage of road salt and limit corrosion of infrastructure and its toxic effects on the environment and drinking water supplies.

“Wisconsin is the only state that contracts out for snow removal,” said Shannon Haydin, the stormwater runoff section manager in the Bureau of Watershed Management for the Wisconsin Department of Natural Resources. “And there are no regulations about how much salt you put down.”

Allison Madison, program manager for Wisconsin Salt Wise — a coalition of organizations working to reduce salt pollution — said 1 to 2 million tons of salt is spread every year on municipal roads, parking lots and sidewalks. That includes about 500,000 tons of salt on state roads and interstates.

“It’s a lot of salt. We’re not on a sustainable trajectory here,” Madison said.

Road salt usage is trending downward dramatically in many parts of the state, Madison said.

“We have seen some local agencies drop their salt use by 30 percent to 50 percent in the last several years,” she said. “All the folks out there clearing our roads want to do the right thing: keep people safe and protect our environment at the same time.”

Motorists have a key role to play, too, Haydin and Madison recently said on WPR’s “The Larry Meiller Show.”

“Changing people’s behavior would absolutely go a long way in reducing the amount of salt we use,” Haydin said.

Road crews could apply less salt if more motorists avoided driving when roadways are not yet cleared of snow and ice.

Haydin said drivers should be “paying attention to the weather the night before and getting up earlier. People should be reminded to slow down and give themselves more time.”

The harmful effects of salt, or sodium chloride, on roads are clear: “It impacts our fisheries. It makes our fish smaller. It can also lead to harmful algae blooms in the summer,” Haydin said.

Unsafe levels of salt are also leaching into drinking water, she said.

Between 2014 and 2024, 36 percent of community wells tested at least once for sodium by the DNR exceeded 20 milligrams per liter.

“That’s the limit recommended for people on a low salt diet,” Haydin said. “So, individuals with high blood pressure may be getting excess salt just from drinking their water every day and not accounting for that.”

And then there’s the damage salt does to personal vehicles and public infrastructure.

“All the salt we put down on our roads can do a lot of damage to our vehicles, but it also prematurely ages our bridges, roads, sidewalks and buildings,” Madison said. “For every dollar that we spend on salt, we’re doing about $10 of damage to our infrastructure. It adds up pretty quick.”

Alternatives to road salt have their own benefits and pitfalls

There are several alternatives to road salt available to municipalities and individuals. But many of those options are less effective and less affordable, Haydin and Madison said.

Madison said she supports brining roadways. Salt brine, she explained, is rock salt diluted with water, which reduces the amount of salt used.

There are also “cousins” of rock salt that can melt ice at colder temperatures. But magnesium chloride and calcium chloride can “cost 20 times as much” and “cause other additional environmental problems that varies from species to species,” Madison said. She added that calcium chloride and magnesium chloride can often do more damage to metals and concrete, respectively.

She said a lot of municipalities have experimented by using agricultural byproducts such as beet juice. The sugars don’t melt ice and snow, she explained, but when added to a brine solution, it slows refreezing and has a less corrosive effect.

“Sugars, though, do end up in our water, just like salt. So, that is a concern,” Madison said. “We don’t want to just apply anything at high rates, whatever tool we’re using.”

Sand, wood ashes and barn lime, when spread on driveways and walkways, can improve traction. They won’t melt snow and ice, but they are good alternatives to salt for homeowners.

The goal, Madison said, is to lessen the amount of road salt municipalities and snowplow operators spread.

“They feel pressure from residents to do more and to get down to bare pavement immediately,” she said. “But if you don’t need to be on the road during a snow event, stay home and wait it out. And if [the amount of road salt used] is a concern to you, let your municipalities know that you would prefer to see them lighten up.”