The Green County Sheriff's Office is investigating Monday morning's traffic accident on Highway 11, just west of County Road G, near Brodhead. Deputies say the head-on collision at about 6:30 a.m. closed the road for approximately four-hours to aid the injured and allow accident reconstruction by the State Patrol. A female driver from one vehicle sustained injuries and was taken to Mercy Hospital and Trauma Center in Janesville. The male driver and passenger in the second vehicle were critically injured and were Medflighted to UW Hospital in Madison. Investigators say seat-belts were used. No names have been released pending notification of relatives.