Police said the incident happened on Friday night as the man was waiting in the drive-thru line at the El Pollo Loco restaurant on Vineyard Avenue and Oxnard Boulevard.
The victim flagged down officers nearby and told them a woman had jumped into his vehicle, brandished a knife and demanded money. She fled with an undisclosed amount of money and the victim's cellphone.
The man told police that he saw the suspect, later identified as 27-year-old Nicole Martin, getting into a tan GMC pickup truck that got onto Highway 101. Officers were able to locate and stop the truck on the freeway.
The victim identified the suspect, and she was arrested for robbery. The male driver of the GMC pickup was questioned and determined not to be involved in the robbery. He was released at the scene.