A deranged driver broke a woman's arm with his bare hands, pummeled her repeatedly and then knocked her fiancée unconscious during a road rage eruption in central Oregon, according to cops and the battered couple.

Jay Allen Barbeau, 49, faces felony assault charges in the brutal Friday night attack that left Megan Stackhouse and Lucinda Mann wounded and reeling at a roundabout in Bend.

"The whole thing was absolutely horrifying," Stackhouse, 34, told The Oregonian/OregonLive — shortly after doctors inserted pins, screws and plates into her fractured right radius.

Mann, 26, remains rattled days later. "He was relentless," she said.

Barbeau, a Redmond resident who used to live in Oregon City and Aloha, was arraigned Monday in Deschutes County court on three counts of assault and single counts of criminal mischief and reckless driving. He remains lodged in Deschutes County Jail, records show.

The recently engaged couple had just left a carnival thrown by the AVID Cider Company and was trying to maneuver their Kia Soul through heavy traffic when they pulled in front of a truck on Southwest Bond Street around 8 p.m.

The truck, which police say was driven by Barbeau, gunned its engine and tailed the women for blocks, driving so close behind them that Stackhouse could not see its headlights or license plate, she said.

Eventually, she said she pulled over at a roundabout where Southwest Brookswood Boulevard and Southwest Reed Market Road meet in order to let the man pass them.

Instead he pounced, according to the women and the Bend Police Department.

The hulking, 245-pound man hopped out his truck and rushed toward the women's car, shattering its rear window and left tail light with a flying fist, Stackhouse and Mann said.

Barbeau then darted over to the Kia's driver side window, which was rolled down, and snatched Stackhouse's right arm, she said. He began to bend and twist it until the arm snapped, she said.

"It was a compound fracture," Stackhouse said. "It was visibly broken."

Barbeau then started punching her repeatedly in the face, which broke the glasses she was wearing, Stackhouse said.

That's when Mann said she got out of the passenger seat and ran around the car toward Barbeau to try and subdue him.

Mann said Barbeau violently grabbed her and thrust her head-first into the concrete. The impact knocked her unconscious and later left her with a concussion, according to the women and court records.

Barbeau began to head back to his truck, where a female passenger who was with him urged they flee the scene, Stackhouse recalled.

Officers arrived and arrested the man before he could, police said. Multiple people witnessed the incident, said Lt. Clint Burley, a Bend police spokesman. Stackhouse and Mann were both taken to the hospital.

As Stackhouse recovers from her injuries, she said one thing keeps running through her mind.

"What would have happened if he had a gun?" she said.

-- Shane Dixon Kavanaugh

skavanaugh@oregonian.com

503-294-7632 II @shanedkavanaugh