Many new vehicles come with an ambient air temperature display. Because air and road surface temperatures typically vary by as much as 15°F, knowing air temperature conditions is not enough to warn you of dangerous black ice.
The patented RoadWatch infrared road surface thermometer alerts you to changes in actual road temperatures as they occur. RoadWatch senses a 1°F change in road temperature in less than one-tenth second. An amber LED lights when the road is 35°F or below to warn you of possible icing conditions.