Chief Bryan Larkin released the findings of an internal investigation into Kovach's fatal crash at a news conference.
Kovach, 26, was responding to a call for help from another officer when she crashed into a bus on Imperial Road South in Guelph on March 14 around 12:30 a.m.
Kovach had been driving around a curve at 115 km/hr when she lost control, as the car spun clockwise, Larkin said.
She was able to regain control of the car, but then encountered ice and lost control again. This time the car went counter clockwise and crossed the centre line.
Her cruiser was travelling at 75 km/hr when it hit the bus, which was going at a speed of around 43 km/hr.
The driver of the bus suffered minor injuries in the collision. There was no one else on the bus at the time.
Although Kovach was not wearing a seatbelt at the time of the collision, Larkin said it would not have prevented her death because of the force of impact.
Kovach's mother questions why daughter didn't wear seatbelt
After Larkin released the report, Gloria Kovach, Jennifer's mother, made her first public comments, saying she will always have questions about what happened.
She said she wonders why her daughter didn't wear her seatbelt, considering she was teased in police college for always wearing a seatbelt.
Earlier, Larkin told reporters that Kovach was asked by her mother to take the day off to go to Ottawa to be with family, but had decided to come to work.
A public funeral for Kovach was held on March 21.
Thousands gathered in the streets of downtown Guelph to watch a procession of more than 6,000 uniformed officers escort Kovach's flag-draped casket to the Sleeman Centre for the funeral service.