A man trying to help a motorist stopped along the Glenn Highway in rush-hour traffic this week was struck by another vehicle and severely injured, with the driver Anchorage police say is at fault now facing assault charges.

Krista Ruesch, 34, was charged with operating under the influence, second-degree assault and reckless endangerment in the Tuesday crash, police spokeswoman Renee Oistad said in a statement. Officers had responded to the collision, inbound on the Glenn near the Fort Richardson exit, at about 4:10 p.m. Tuesday.

“A Dodge Durango was pulled over onto the right-hand shoulder of the roadway with a flat tire,” Oistad wrote. “An adult male had pulled over to provide assistance to the female driver of the Durango. The adult male was standing next to the driver’s door of the Durango when both the male and the Durango were struck by a passing white sedan.”

The man was taken to a local hospital in serious condition.

A charging document against Ruesch, written by Assistant District Attorney Katholyn Runnels, said that she had been driving the sedan with her two children as passengers. A breath test of Ruesch for alcohol came back negative, but she didn’t perform well in field sobriety tests; officers said she had “slurred speech, droopy and even partially closed eyes, and that she swayed from side to side as she spoke.”

“Ruesch reported that she has bipolar disorder and is on at least seven different medications for this condition,” Runnels wrote. “She stated that she was driving on the highway and recalled approaching ‘an object,’ but did not remember that ‘object’ being a vehicle, and swerved to miss it but was unable to do so.”

A family member visited the crash site to pick up Ruesch’s children, Runnels wrote.

Ruesch was arrested and taken to the Anchorage Jail, where she was arraigned Wednesday. Court records show her bail was set at $250, on which she was released.