Did you have your vehicle lights turned on Tuesday morning?

A dense fog advisory was issued by the National Weather Service for the Hays area until 10a.m.

Visibility in Hays was less than a quarter-mile, as reported by the KSU Agricultural Research Center.

Kansas law requires motorists to use headlights when the windshield wipers are operating.  Headlights are also required if visibility is less than 1,000 feet.