An 18-year-old woman suspected of texting while driving set off a chain-reaction crash Monday that injured three people and closed a major west Santa Rosa thoroughfare for more than an hour, police said.

Anna Bostrom of Santa Rosa admitted to being on her cellphone while driving north on Stony Point Road, Santa Rosa traffic Sgt. Summer Gloeckner said Tuesday.

“She’s at fault for texting and driving, and unsafe speed,” Gloeckner said.

Traffic was coming to a stop near Hearn Avenue around 2:45 p.m. when Bostrom’s Honda Pilot rear-ended a Honda Civic, driven by Steven Jefferies, 69, of Santa Rosa, police said.

“The guy in front of her saw her coming and tried to swerve, bracing for the impact,” Gloeckner said. “She hits him and pushed him into the southbound lane. She hits another southbound car head-on and sends another car into a tree.”

The two southbound drivers were Karishma Kumar, 26, and Mario Orozco, 59, both of Santa Rosa.

Santa Rosa police and firefighters found debris strewn about the roadway and off to the side. Bostrom’s SUV was damaged, while the other three vehicles were totaled, Gloeckner said.

Bostrom escaped injuries, police said.

Kumar, who was driving a Honda CR-V, suffered a broken arm and a significant knee injury, Gloeckner said. Orozco, who was in a Honda Accord, and Jefferies had minor injuries, she said.

The three were taken by ambulance to area hospitals. Kumar remained at Santa Rosa Memorial Hospital Tuesday in fair condition, a hospital spokesperson said.

The crash happened as area schools were starting to let out, and significantly backed up traffic after temporarily shutting down a section of Stony Point Road, police said.

You can reach Staff Writer Randi Rossmann at 707‑521-5412 or randi.rossmann@pressdemocrat.com. On Twitter@rossmannreport.