A confusing, chain-reaction crash involving four cars and two suspected drunken drivers left a Santa Rosa woman, her young son and a passenger in her car severely injured after they climbed out of their disabled Volvo on Highway 101 and into the path of more trouble Sunday morning, according to the CHP.

The 2-year-old's mother, Bertha Alicia Vazquez, 39, appears to have provoked the early morning wreckage, though just how she became entangled with a Honda Accord and caused the first crash was not entirely clear Sunday night, CHP Officer Marcus Hawkins said.

An off-duty Cotati police sergeant reported seeing Vazquez race past him on northbound Highway 101 in Rohnert Park at speeds approaching 90 mph in the moments before the 3:38 a.m. crash, Hawkins said.

Then near Todd Road, her Volvo sedan collided with the Honda Accord, driven by Gloria Noemi Aquino, of Santa Rosa, causing both cars to spin out of control, he said.

Aquino's car came to a stop on the shoulder, its front bumper detached. She was uninjured, Hawkins said.

The Volvo ended up sideways across two lanes, pointing west.

Vazquez got out of the car as if to walk around the front of it to the passenger side, so she could remove her son, Armani Paez, Hawkins said.

But her 25-year-old passenger, Gregorio Galvez, climbed out faster, grabbed the child from the backseat and had him in his arms just as another car, a Toyota Corolla, struck the Volvo in its path, Hawkins said.

The Volvo spun again, striking its three occupants in the street, knocking the boy loose from Galvez's arms and sending them all flying in different directions, Hawkins said.

"It was a horrible scene," CHP Officer Nenad Gorenec said.

A witness reportedly grabbed the boy from the road and rushed to the shoulder, where the child was handed to bystanders for safety until firefighters arrived.

And then, another car, a red Honda Civic hatchback, came upon the scene and struck Vazquez, said Hawkins.

The impact apparently threw her into the windshield of the car, driven by Lucien Albert Lippi, 41, of Healdsburg.

He smelled of alcohol and was arrested for suspected drunken driving, causing injury, after submitting to field sobriety checks. He remained at the Sonoma County Jail on Sunday night, with bail of $100,000, jail personnel said.

Vasquez suffered major injuries and was at Santa Rosa Memorial Hospital, as was Galvez, a homeless man upon whom Vazquez said she had taken pity, Hawkins said. She told authorities the two had been strangers, but that she wanted to help him and was driving him from Contra Costa County to a Santa Rosa homeless shelter when the crash occurred, Hawkins said.

Vazquez also was believed to have been under the influence of alcohol and was arrested for suspected drunken driving and released to medical staff, Hawkins said.

Her son was taken to Children's Hospital in Oakland, but appeared to have lesser injuries than the two adults, Rincon Valley Fire Capt. Neil Nicholson said.

You can reach Staff Writer Mary Callahan at 521-5249 or mary.callahan@pressdemocrat.com. You can reach Staff Writer Derek Moore at 521-5336 or derek.moore@pressdemocrat.com.