MINNEAPOLIS (WCCO) — Here in Minnesota, ice is welcome on ponds and rinks, but on the runways at the Minneapolis-St. Paul International Airport – not so much.

In the midst of the snow and ice, there’s a unique tool being used to help airplanes land safely and smoothly.

Early Friday morning, crews at MSP Airport used their “Surface Friction Tester” vehicles to determine how slick the runways were after Thursday’s wet weather.

Using a small, fifth wheel and a formula that calculates friction, the results measured by a computer inside the vehicle are an important factor in determining whether a runway should stay open.

The airport has four of these specially-equipped cars ready for duty every day of the year.

Crews drive over the runway once to establish a base level, once again after it’s plowed and swept, and one more time after that.

“The last few days have been a challenge because first it started with snow and then it transitioned to rain,” said Jose Beltran, assistant manager of airside operations for the Metropolitan Airports Commission.

The information gathered is sent to air traffic control, pilots and individual airlines.

“No one wants to have a runway closure, but sometimes you absolutely have to for safety concerns,” said Bob Johnson, assistant manager of airside operations for the Metropolitan Airports Commission.

The last time a runway was closed here was during the April blizzard and at a time when thousands of holiday travelers are flying, nothing is more important than a safe takeoff and landing.

“Safety is always the most important issue out here. Safety is always paramount and that’s what we strive for every day and, frankly, we achieve it,” Johnson said.

The Friction Tester is also used during the summer because airplanes’ wheels can leave behind a rubber residue on the runway that can make things slippery.