Method and device for generating a signal warning of slipperiness on a roadway

A method of generating a signal indicating a condition suitable for formation of slipperiness on a roadway, the method comprising:

• using an infrared (IR) radiation source to emit IR radiation in a direction of at least one reference surface arranged in or on the roadway or arranged in or on a location adjacent to the roadway;
• receiving, by a road condition sensor, backscattered IR radiation from the at least one reference surface, the road condition sensor being oriented relative to the at least one reference surface to capture IR radiation backscattered from the at least one reference surface;
• evaluating the backscattered IR radiation from the at least one reference surface to detect a slippery condition on the at least one reference surface;
• and
• outputting a detection signal if the slippery condition is detected from the backscattered IR radiation,
• wherein the slippery condition forms on the at least one reference surface before the slippery condition forms on the roadway, and
• wherein the at least one reference surface is comprised of a roughened surface texture and is formed of a material different from a material forming the roadway.