Jack Del Rio Arrested For OWI After Allegedly Hitting Street Sign

11:11 AM PT -- Wisconsin head coach Luke Fickell just announced Jack Del Rio has resigned from his position on the Badgers' staff following his arrest.

"It's a tough situation," Fickell said, "decisions that all of us have to be able to take full responsibility for. So that's what Jack will do and we'll continue to move forward."

Ex-NFL head coach and current Wisconsin football adviser Jack Del Rio was busted for driving while intoxicated in Madison ... after cops say his car drove into a street sign and fence.

61-year-old Del Rio -- who joined the Badgers' staff under Luke Fickell in August -- was arrested after officers were called to the scene around 12:35 AM on Friday.

Madison PD tells TMZ Sports -- a vehicle hit a street marker, broke a fence and came to rest in a yard ... and witnesses directed cops to a man who was walking away from the area.

Once officers made contact with Del Rio, they say he showed signs of impairment and admitted to driving the vehicle involved in the crash.

Del Rio was arrested for first-offense Operating While Intoxicated/Impaired and released to a responsible party.

Wisconsin released a statement on the matter ... saying it is aware of the arrest and takes the matter "very seriously" as it gathers more information.

Del Rio was a third-round draft pick out of USC in 1985 ... and was a linebacker for the Saints, Chiefs, Cowboys and Vikings over the course of his 10-year career.

He went on to be the head coach of the Jaguars from 2003-11 and Raiders from 2015-17 ... and also served as a defensive coordinator for the Broncos and Commanders.

He has a 93-94 record as a head coach.