A mother and daughter were walking their dog in a marked crosswalk in their West Hills neighborhood when they were fatally struck by a motorist, police said a preliminary assessment had showed.

The victims were struck about 8:20 p.m. Monday on Roscoe Boulevard at Jason Avenue, according to Los Angeles Police Department Detective Bill Bustos. When police arrived — before paramedics — area residents were trying to perform CPR on the pair.

The younger woman and the dog, a Labrador, died on scene, while the older woman died at a hospital, Bustos said.

The women were later identified by the corner’s office as as Erica Botz, 31, and 69-year-old Pia Botz, both of West Hills.

Coworkers of Pia Botz visited the crash site, saying she was beloved at the Encino insurance company where she worked. She often picked flowers for her coworkers from her own garden, they said.

A maroon Subaru SUV with New York plates was being driven by a Los Angeles resident who was being followed by his wife, in a white sedan with their baby, the detective said. They were running errands when the SUV hit the victims, Bustos said.

Traffic investigators believe the women were in the crosswalk, he said.

“We don’t know what happened. Obviously, there was a mistake, there was an error that translated into a vehicle code violation that resulted in a traffic collision, a very tragic traffic collision,” Bustos said.

The SUV and the white sedan stopped and remained at the scene.

Police were working to interview witnesses and take measurements to determine what caused the crash, Bustos said. He reminded news media that April is Distracted Driving Awareness Month, urging motorists to focus on driving.

A local resident who was walking his dog in the area Wednesday morning — wearing a bright yellow shirt — said the intersection is dangerous, with most cars failing to obey the posted 40 mph speed limit.

“Unfortunately, what happened last night almost happens every day,” resident Lamar Hudson said. “I don’t even cross this street when it’s dark. It’s just not safe.”

Bustos said Monday night that investigators did not know if speed was a factor.

Others said the poor lighting in the area and a crest farther down Roscoe Boulevard contributed to the danger.

Councilman Mitch Englander, who represents West Hills, said engineers had already visited the intersection with plans to make it safer.

The Fire Department initially said the victims were a 70-year-old female and a 14-year-old female.