Wisconsin Governor Scott Walker signed a bill that requires drivers to turn their headlights on when weather conditions limit visibility into law on Monday, February 29, 2016.

The language, added by statute, defines the type of weather conditions: 340.01 (43d) “Period of limited visibility” means any time that weather conditions limit visibility such that objects on a highway are not clearly discernible at 500 feet from the front of a vehicle.

The Wisconsin State Patrol said that limited visibility means that you can’t see something 500 feet away, which is a little less than two high...