The Alberta Serious Incident Response Team says no charges will be laid.
The agency investigated after the 21-year-old woman was injured in Calgary in October.
She had driven a quad off her family's property near Gleichen (GLEE'-shehn) and onto a highway, where she maintained speeds with other cars and swerved across lanes of traffic.
A Mountie followed her from a distance with emergency lights to hold back traffic.
Police in Calgary planned to catch her at a traffic stop after she got on Deerfoot Trail but, before they could, the woman lost control of the quad and hit a fence.
She was taken to hospital with serious injuries. ASIRT says she continues to recover at home.
In a news release, the agency says motorists provided video clips and details that cleared officers of any wrongdoing.
"The evidence confirmed that all of the police officers involved attempted to protect the young woman and everyone else on the road."