A Pleasant Grove mother died Tuesday morning in an early morning accident on the southbound Golden State Freeway.

Stephanie M. Keiper, 29, was driving the family’s 1994 Toyota Camry along the I-5 when the car drifted onto the west shoulder and hit the guardrail, causing the vehicle to overturn and go down the hillside, coming to rest on its roof.

Investigators from the California Highway Patrol said that Keiper may have fallen asleep at the wheel.

Also in the car were her husband, Shane Keiper, Sr. 35; her two children, Shane Keiper Jr. and Aden Keiper, and another minor, Aaron N. Selfridge. Shane Keiper Sr. was able to climb up the embankment and flag down help. Stephanie was trapped in the wreckage and suffered fatal injuries; the passengers suffered only minor injuries and were transported to Henry Mayo Newhall Memorial Hospital.

Alcohol is not considered a factor in the accident, which is still under investigation.