A 51-year-old bicyclist was struck Monday night on West Orange Grove Road near North La Cholla Boulevard, authorities said.
The man was treated by paramedics before being taken to University of Arizona Medical Center with serious injuries, said Capt. Adam Goldberg, a Northwest Fire District spokesman.
The crash between the bicyclist and a truck was reported at 7:30 p.m., Goldberg said. The bicyclist was not wearing a helmet, and his bicycle did not have reflective lights, he said.
Goldberg said the bicyclist was exiting a shopping center parking lot onto Orange Grove and failed to stop at a stop sign, and was struck by the truck traveling eastbound.
The driver of the truck remained at the scene and cooperated with Pima County Sheriff's Department deputies, said Goldberg.