SAN RAFAEL (CBS SF) — A mother was under arrest on DUI charges and her 4-month-old baby in protective custody Sunday after a Mill Valley police officer pulled her from Highway 101 where she was wandering into traffic, forcing on-coming drivers to swerve to avoid hitting her and her child.

The unidentified mother was being held on DUI and child endangerment charges.

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The California Highway Patrol said the incident took place at around 1:30 p.m. on northbound 101 near the SR-131/East Blithedale exit in Mill Valley.

Frantic 911 calls came into dispatch with reports of a woman holding a baby, walking in lanes of traffic.

“Horrified callers told dispatchers the woman was in lanes and that vehicles were slowing and swerving to avoid her,” the Marin CHP office posted on Facebook. “One concerned citizen slowed down to try to see if they could help when the woman attempted to force her way into the passenger side of the vehicle.”

As CHP officers were rushing to the scene, a Mill Valley police officer nearby heard the call and was able to locate the woman. The officer quickly helped the woman and baby into the car and took them off the freeway to safety.

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Arriving CHP officers determined the mother was in an altered state “likely due to being under the influence of a drug.”

They learned that after her car broke down on the State Route 131 on-ramp to northbound 101, she decided it would be best to abandon the car, take her baby and walk on the freeway to get help.

After a thorough DUI investigation, officers arrested the mother for driving under the influence of a drug.

As the mother was being taken to jail, the four-month-old was taken into the care of CHP officers as they awaited the arrival of Child Protective Services.

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While they awaited the CPS arrival, the labor and delivery staff at MarinHealth send over some supplies and formula. The child did not suffer any physical injuries in the incident.