Officer Melissa Sprangers ran into another squad car while responding to a request for backup last fall. The crash totaled both cars and sent Sprangers and another officer to the hospital.
Sprangers had been going up to 67 mph and was speeding at 62 mph when her vehicle hit the other squad, police documents showed. She was not wearing a seatbelt.
Fond du Lac police suspended her for 20 days. She had been suspended for one day for a March, 13, 2013, crash in which investigators determined she was driving too fast. She also received a written warning for a Nov. 15, 2012, accident in which she hit a parked car.
Fond du Lac Police Chief Bill Lamb admonished Sprangers for having three crashes in about a year and warned her that additional ones would result in harsher punishment.
"Further violations of city policies ... will not be tolerated," Lamb wrote in a Jan. 2 letter to Sprangers obtained by the newspaper.
Assistant Police Chief Steve Klein said the 20-day suspension showed how seriously the department considered the issue.
"It was quite a lengthy suspension for this officer which sends a strong message that we are bound by the law to drive with due regard when operating an emergency vehicle," he said. "This officer has been put on notice that any future actions such as this are unacceptable. We've already dealt with a warning and now two suspensions and we expect there will not be any future violations."
Spranger has been required to undergo remedial driving training. All officers complete a one-day driving course every two years.
Klein said officers have to be prepared for scrutiny.
"The public expects the police department to operate and respond to emergency situations in a safe manner," he said.