(Photo by Stina Sieg - KJZZ)

This photo, from Christmas Day 2015, shows just how bad U.S. 180 can get on winter days

Snow in the forecast plus a three-day weekend often means one thing in Flagstaff: traffic. The Arizona Department of Transportation is warning motorists to be prepared for delays.

During the winter, traffic tends to backup along U.S. 180, a highway that heads north out of the city toward the Arizona Snowbowl and other recreation areas. ADOT spokesman Steve Elliot said his department began warning people about the traffic last year.

And this winter, he’s seen fewer Tweets to ADOT asking about why that stretch of highway is so slow.

“So I think people who are going in there are knowing what to expect, and hopefully are making some choices about when they decide to come back, because there really is one route back to Flagstaff,” Elliott said, “and if everyone heads home at the same, it can be pretty congested.”

Elliott adds drivers should never park along the highway’s shoulder.

“It’s dangerous, and it actually can make the traffic worse,” he said. “So, we tell people, they really, really, really need to get off the highway to play in the snow. Park safely in designated areas.”

ADOT recommends motorists taking that route should bring winter coats, blankets, a fully charged cellphone — and plenty of gas.

People can check if recreation areas are open and if they have snow on the Flagstaff Chamber of Commerce website or can call a snow-play hotline at (844) 256-SNOW.