A man police described as an active gang member was arrested Wednesday following a road-rage incident in Santa Rosa in which he allegedly threatened a driver and pulled a gun on her twice, officials said Thursday.

“It was one person cut in front of the other and lack of patience was really what precipitated the entire thing,” said Sgt. Tommy Isachsen, a spokesman for the Santa Rosa Police Department. “It was a minor vehicle incident, not being courteous to each other and sharing the rules of the road.”

Arrested were Gerardo Covarruvio Mendoza, 32, of Santa Rosa, who has a lengthy criminal record and a conviction of being an active gang member, and 18-year-old Carley Renee Tolonen, also of Santa Rosa, who was driving Mendoza around when the road-rage incident erupted.

A woman called Santa Rosa Police about 4:45 p.m. to report that a male passenger, believed to be Mendoza, had gotten out of a car at a traffic light at Stony Point and Sebastopol Road, walked up to her vehicle and threatened her while brandishing a gun, Isachsen said.

The victim told police she quickly drove away only to be followed by the car the gunman was riding in, he said. On Todd Road, the suspect car pulled in front of the victim’s vehicle and stopped in the middle of the road, causing her to slam on her brakes, he said.

The same male passenger got out of his car and threatened her a second time with the firearm before fleeing the scene, Isachsen said.

The victim quickly called police and numerous officers responded. They caught up to the suspects, pulling their car over in the 500 block of Todd Road. Police searched the car and found a gun and marijuana that appeared to be packaged for sale, Isachsen said.

Mendoza was arrested on suspicion being a felon in possession of a firearm, making criminal threats, brandishing a firearm, conspiracy, possession of marijuana for sale, and transporting marijuana for sale. His driver, Tolonen, was arrested on suspicion of possessing a concealed firearm and conspiracy.

Both Tolonen and Mendoza were booked at the Santa Rosa County Jail.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twitter: @SarRavani