FAIRBANKS (AP) — Annual bouts of freezing rain in Interior Alaska have spurred road crews to use a tool that they wouldn’t have considered until recently — trucks loaded with massive tanks of salty brine.

The Alaska Department of Transportation purchased a pair of roughly 2,000-gallon brine tanks three years ago and began using them consistently last year. Sand trucks also have been equipped with smaller tanks of brine, which blend it into the grit to help the sand better stick to slippery roadways.

Their use wouldn’t have been considered in Interior Alaska not long ago, when five straight months of sub-freezing temperatures were the norm. But winter drizzles have become a fairly common occurrence in the past decade, adding a new challenge for road maintenance.

When a heavy dose of freezing rain covered Fairbanks in November 2011, Fairbanks roads never recovered. It was then that DOT officials realized something needed to be done.

“That’s basically what’s driving this,” said Dan Schacher, the local DOT maintenance and operations supervisor. “We lived with that ice for the rest of the year.”

On Sunday through Tuesday, as temperatures crept above freezing, brining was occurring 24 hours per day to cover slippery spots near local railroad crossings and intersections. Crews paid special attention to a notoriously slick section of the Steese Highway between Chena Hot Springs Road and Farmers Loop that DOT workers have nicknamed “the luge.”

The brine trucks are capable of dispensing as much as 10,000 gallons of brine per day, spraying as much as 30 gallons per lane mile.

Periods of winter rains aren’t unprecedented in the Interior, but even longtime residents could understandably believe they almost never used to happen. National Weather Service meteorologist Rick Thoman calculated winter rain episodes of at least a tenth of an inch for roughly the past century and found only four examples from 1970 to 2000.

In contrast, Fairbanks has had winter rain in three of the past four years, including a storm last November that knocked out power in much of the Interior.

There were a few decades when winter rain was more common, most notably six examples during the 1960s. But Thoman noted that road conditions weren’t as big a factor then, since Fairbanks was a much more compact community. The Parks Highway, for example, didn’t exist.

“Even though we’ve seen these cycles, it was in a much different cultural and social environment,” Thoman said.

The shift led DOT to explore the use of road brine, which is commonly used in the Upper Midwest. A pair of $35,000 brine tanks was purchased to add to the existing fleet of DOT vehicles. A machine that blends the saltwater solution cost an additional $130,000.

Schacher said the brine was used sparingly the first year as crews experimented to figure out how it would work best in a low-humidity environment where the temperature rarely gets above freezing.

The Alaska University Transportation Center participated to research how to best use the solution in the Interior. Adding it to local roads before rains arrive has been found particularly effective, since it allows ice to be more easily peeled away.

AUTC Director Billy Connor said that developing weather protocols has been a large part of the process.

“We’ve been working on a decision model to let them know what to do at the right time,” Connor said. “That’s the important thing to know.”

The other advantage, Schacher said, is purely financial. He points to a 15,000-ton mountain of sand behind the DOT building. At $23 per ton, it’s not a cheap solution for dealing with slippery roads.

A gallon of brine costs 18 cents, which is a relative bargain. Not only is the brine more effective, he said, but it doesn’t need to be swept off streets after breakup like sand does.

“We’re dollar driven — we’ve got to do what we can as cheaply as we can,” Schacher said.

Schacher said he’s had numerous calls from motorists surprised at the sight of a brine truck in Fairbanks. Many people are concerned about the possibility of vehicle rust, but Schacher said it shouldn’t be a concern for modern vehicles at the volumes used in Fairbanks.

Connor said evolving road conditions have become a reality as Alaska’s climate warms and that it’s important for maintenance crews to adapt.

“With the changes we’re seeing in our climate, we just can’t do business as usual,” Connor said.