Question: Is there a law that requires headlights to be on when visibility is limited or when windshield wipers are required?
Answer: The state of Wisconsin requires that motor vehicles operating on a roadway during the hours of darkness use headlights, taillights and clearance lamps which are equipped on the vehicle. In addition to headlights, a vehicle is also allowed to use adverse weather lamps or auxiliary lamps (most commonly fog lights), provided that there are not more than four of any such lights illuminated at any one time when the vehicle is being driven upon the roadway.
The state of Wisconsin does not have a specific requirement that mandates motorists to use headlights simultaneous with their windshield wipers. However, since using headlights increases the visibility of your vehicle to other motorists; the use of headlights during inclement weather can help make the roadways safer for you and for other motorists.
The state statutes governing this topic are: 347.06, 347.09, and 347.10.