District Police Chief DSP George Abdu Rakman said Salmah binti Awang Jambul succumbed to serious head injuries in the 2.35pm mishap.
He said the 55-year-old 4WD driver was heading from Keningau to Kota Kinabalu while Salmah was heading to Kg Benoni from here prior to the incident.
"It was believed that the 4WD driver lost control of the wheel and went to the opposite lane and collided with the Proton Iswara that was coming from the opposite direction.
"The driver sustained minor injuries on his face and legs, and has been detained to facilitate investigations under Section 41(1) of the Road Transport Act 1987," he said Thursday.
George also called on any individual who may have witnessed the accident to come forward and facilitate the investigation.
Fire and Rescue personnel were alerted at 2.40pm and it took them 15 minutes to extricate Salmah from her vehicle.