OAKLAND (CBS SF) — Oakland police said Friday that they could not determine who was at fault in a vehicle collision involving Mayor Jean Quan last month but they have ruled out the use of cellphones by either driver as a factor.

The collision occurred shortly after 5:30 p.m. on June 8 near the intersection of 26th and Market streets in West Oakland.

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Quan told reporters at the time that she was driving between two community events when another vehicle struck the left rear tire of her car.

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Police said Friday in a statement that an investigation had found the primary factor in the collision was a failure to stop at a red light signal.

“The driver most at fault for the collision was unable to be determined due to conflicting accounts,” the statement said.

Quan pointed to the police report as support for her statements to reporters after the collision that she had not been using her cellphone while driving.

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“I stand by my original statement that I do not believe I ran the red light,” Quan said in a statement, noting that there were no witnesses to the actual collision.

“The damage to the car reveals that I was hit from behind; the impact spun my vehicle around and flattened my left rear tire,” Quan said.

Quan, who is facing 16 opponents in her re-election bid in the November election, submitted her cellphone records to Oakland police to confirm her assertion that she wasn’t on her phone at the time of the collision.

Quan’s driving came under question previously over photos showing her using her cellphone without a hands-free device while driving.

Quan also acknowledged in June that she was cited for a “rolling stop” while going through an intersection in Fremont in April 2013.

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