Road salt loses its effectiveness at temperatures lower than 15 degrees

With dropping temperatures, especially in the early morning hours, the Minnesota Department of Transportation strongly urges drivers in the Arrowhead Region to be especially alert for a phenomenon commonly called “black ice,” which can rapidly develop during cold temperatures.
Black ice is almost invisible and can easily catch drivers off guard.
It quickly forms in cold weather when the air temperature is just slightly warmer than the pavement, which causes moisture to rapidly freeze, creating a very thin and almost transparent layer of ice on the roadway.
Black ice can form on heavily congested highways from auto exhaust emissions, tire friction and moisture vapors given off by industries located adjacent to the highway.
In addition, black ice often forms on roadways in shaded areas, near lakes and rivers, in tunnels and on overpasses.
Although salt and sand can help minimize the effects of black ice, road salt loses its effectiveness at temperatures lower than 15 degrees.
According to Mn/DOT, motorists can increase their safety by observing the following tips
1. Be aware that black ice is almost invisible. It can form on asphalt or concrete pavements
2. Be especially careful on bridges, overpasses and tunnels and in the early morning when the air temperature is rising faster than the pavement temperature
3. Use extreme care when driving on roadways where ice may have formed. Applying pressure to your brakes while on ice can easily cause a vehicle to skid.
4. Do not use cruise control during winter driving conditions. When using cruise control your vehicle will automatically accelerate when the cruise control system senses a grade increase. On slippery roads, this sudden & unanticipated speed increase can cause the driver to loose total control of the vehicle.
5. Use a safe lower speed for winter driving conditions, regardless of the posted speed limit.
6. Keep a safe distance from the vehicle in front of you.
7. Avoid using a cell phone or other electronic communication device while driving.
8. Remember: common sense is the best rule to follow when driving in inclement conditions.