Minn. Stat. § 160.215: SNOW REMOVAL; SALT AND CHEMICALS RESTRICTED.

In order to:

(1) minimize the harmful or corrosive effects of salt or other chemicals upon vehicles, roadways, and vegetation;

(2) reduce the pollution of waters; and

(3) reduce the driving hazards resulting from chemicals on windshields;

road authorities, including road authorities of cities, responsible for the maintenance of highways or streets during periods when snow and ice are prevalent, shall utilize such salt or other chemicals only at such places as upon hills, at intersections, or upon high-speed or arterial roadways where vehicle traction is particularly critical, and only if, in the opinion of the road authorities, removal of snow and ice or reduction of hazardous conditions by blading, plowing, sanding, including chemicals needed for free flow of sand, or natural elements cannot be accomplished within a reasonable time.