Metro area drivers will continue to face ice-covered highways through Sunday and possibly into Monday as plunging temperatures counteract the heavy doses of road salt and slow the melt.

While sunshine Saturday helped melt some icy stretches, officials still advised people to avoid driving through the weekend because the salt and chemicals that snowplows are dropping by the ton are taking longer to work in the cold.

“The metro system is certainly still a challenge,” said Kevin Gutknecht, spokesman for the state Department of Transportation. “I want to counsel patience. This is the worst compacted snow we’ve seen in a long time. Chemicals are slowly but surely starting to work. It just takes time with these ­temperatures.”

Monday’s commute should be better, though crews will have a better sense of that by Sunday afternoon. Across Minnesota, the State Patrol had responded to 964 crashes, more than 2,300 vehicles off the road, 1,082 stalled vehicles, 74 jackknifed semitrailer trucks and 4,414 calls for service from Thursday through Saturday afternoon.

While metro drivers dealt with slick roads, outstate drivers faced poor visibility, especially blinding, blowing snow in southern Minnesota. Gov. Mark Dayton declared a state of emergency on Friday, directing the Minnesota National Guard to assist any stranded motorists.

MnDOT continued to classify metro road conditions as difficult, with traffic slowing to speeds that often topped out at 20 miles per hour on interstates.

The State Patrol advised drivers to check for road conditions, but said that if in doubt, stay home.

Gutknecht said about 200 plows are working 24/7 on metro roads, putting down tons of salt and brine, and using different blades to try to scrape the ice. But the salt, which he said still remains the best tool against ice, works best at temperatures above 20 degrees — something the metro isn’t forecast to reach this week.

“In some areas, it’s starting to work, but it just takes time,” he said. Both St. Paul and Minneapolis have ended snow emergency parking restrictions. But to clear the way for emergency crews on narrow streets, Minneapolis put winter parking restrictions into effect. Beginning at 8 a.m. Sunday, parking is banned on the even-numbered side of non-snow emergency streets through April 1.