Douglas County investigators Wednesday arrested an 18-year- old driver from Highlands Ranch after tracing the black SUV he was driving to a hit-and-run in front of a King Soopers in which a woman was seriously injured.

The incident occurred at 3:57 p.m. outside the store at 8673 S. Quebec St. in Highlands Ranch.

Peter Mazula, a security officer at Highlands Ranch High School, said he had just arrived with his co-worker Judy Trengen, a receptionist at the school.

Trengen recently suffered a broken arm, Mazula said, so he had given her a ride to the store.

"We started walking toward the entrance when, all of a sudden, I hear this honking," he said.

"There was this car behind us. I turned and looked at the guy and mouthed the words, 'What's your problem?'

"He gunned the engine. If I hadn't jumped out of the way, he would have run over my feet.

"All I can think about is where's Judy?" he added. "Then I looked down and saw her legs."

Mazula dialed 911. He was able to provide a description of the suspect, the sport utility vehicle and the licence plate.

Deputies arrested Austin Davis. He is being held in the Douglas County Jail on investigation of vehicular assault, failing to remain at the scene of a serious injury accident, reckless driving and driving under the influence of drugs and alcohol.

Trengen was rushed to a local hospital where she is doing OK, Mazula said.