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News Release

January 21, 2003

State agencies issue safety alert on 'black ice'


ST. PAUL, Minn. – The Minnesota Departments of Transportation and Public Safety today issued a safety alert warning drivers of black ice. Black ice forms when the air temperature is warmer than pavement, which causes moisture to rapidly freeze and create a thin, transparent layer of ice on the roadway. Mn/DOT's Traffic Management Center reported an increase in the number of crashes in the Twin Cities during last week's cold snap. The Minnesota Department of Public Safety reported that icy conditions, including black ice, were contributing factors in more than 12,000 crashes in Minnesota in 2001, which resulted in 47 deaths.

"Black ice can be one of the most dangerous conditions on winter roads," said Lieutenant Governor Carol Molnau who also serves as Mn/DOT Commissioner. "It is almost invisible and can catch drivers off guard," she added. Black ice is clear and appears black because the dark asphalt surface underneath shows through. It can form on heavily congested highways from auto emissions, but other roads are susceptible including those in shaded areas, near lakes and rivers, in tunnels and on overpasses.

Drivers can increase safety by observing the following tips:

  • Be aware that black ice is almost invisible.
  • Be especially careful on bridges, overpasses and tunnels and in early morning when the air temperature is rising faster than the pavement temperature.
  • Never brake while driving on ice. Applying pressure to your brakes while on ice will cause a vehicle to skid. Brake only during your approach.
  • Keep your distance. The distance needed to stop on ice is twice as long as under normal driving circumstances. Keep at least a three-car distance from the vehicle directly in front of you.

Black ice is neutralized with salting and sanding. However, drivers should be aware that salt loses its effectiveness at about 15 degrees and colder. In temperatures below 15 degrees, Mn/DOT uses either sand or de-icing liquids that are effective at lower temperatures.
Travelers in Minnesota can get up-to-date information on road conditions, construction and weather reports from Mn/DOT's 511 traveler information service. By phone, dial 511 (not available on Verizon) or on the Internet at

Dial up or log on before you go.

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Sonia Pitt, Mn/DOT
Telephone: 651/296-8895
Cell phone: 651/402-1395

Kevin Smith, DPS
Telephone: 651/296-8383
Cell phone: 612-760-3274


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395 John Ireland Blvd.
Mail Stop 150
St. Paul, MN

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Fax: 651/297-4776