The Alberta Serious Incident Response Team says the 21-year-old drove the quad off her family's property near Gleichen and onto a highway on Sunday.
A Mountie spotted her swerving from lane to lane and followed her from a distance with emergency lights holding back traffic.
She eventually made it onto Calgary's Deerfoot Trail, where she was going 80 km/h.
When Calgary police joined the pursuit, the woman exited the freeway and lost control of the quad, hitting a fence.
She was thrown from the vehicle, landed on a bicycle path and was taken to hospital with serious injuries.
ASIRT says in a statement that its investigators are examining a video taken from a police helicopter of the pursuit and the crash.
"This evidence is currently being reviewed, but it appears the RCMP and (Calgary Police Service) officers involved took actions to keep the woman safe."
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