The incident occurred at around 1.45pm on Wednesday when the cyclist, a 48-year-old woman from Preston, was stationary at traffic lights at the junction of Corporation Street and Ringway.
A large, white van approached the bike and collided with it before leaving the scene. The cyclist was knocked to the ground, breaking her right arm.
We are now appealing for anybody with information or who has dash-cam footage of the collision to get in touch.
PC Stuart Hart, of the Roads Policing Unit, said: “A collision occurred between a van and a bike, leaving the cyclist with a broken arm.
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“We would now like to piece together what happened and are appealing for anybody who saw the collision or has dashcam footage of it to get in touch. Similarly if you know who the van driver may be, please let us know.”
Anybody with information is asked to contact police on 101, quoting log number 639 of March 2.