DENVER -- Northbound lanes of Interstate 25 near Broomfield were closed Thursday morning after a double-rollover accident that left one car upside down and another upright in the median.

Law enforcement authorities shut down the north-south artery at Colorado Highway 7 between 7:20 and 10 a.m.

Investigators said a 21-year-old woman was the only one injured and her injuries were not life-threatening.

A 2-year-old boy in the vehicle with her was also transported to St. Anthony's Central. He was checked out and had no injuries from the accident. He was secured in a child safety seat when the accident occurred, police said.

Police said the woman was traveling north on I-25 when she tried to pass a semitrailer. She clipped the front of a semitrailer and lost control of her car, slamming into an abandoned vehicle on the east shoulder of I-25, police said.

The abandoned vehicle flipped over. Then a second northbound semitrailer struck her vehicle.

The woman was ejected and airlifted to St. Anthony's Central Hospital with an apparent serious head injury.

The drivers of the semitrucks were uninjured.

The case is under investigation by members of the Broomfield Police Department Technical Accident Investigation Team.

If anyone witnessed this accident, they are asked to call the Broomfield Police Department at 303-438-6400.

Some northbound traffic managed to get by on a frontage road, but motorists who chose to wait through the I-25 tie-up encountered long delays.