Spokane police are at the scene of a pedestrian-involved collision that landed a 75-year-old man in a hospital tonight. Police say the unidentified pedestrian was transported to Providence Sacred Heart Medical Center with a serious head injury; he’s in critical condition. Police are still piecing together how the collision occurred. Because of the extent of the man’s injuries, detectives from the traffic division of the Major Crimes Unit responded, but no arrests have been made at this time. Police do not believe the driver, who underwent field sobriety tests at the scene, was under the influence of drugs or alcohol. The unidentified driver, who was in a large red pickup truck, is in his 20s and was coming home from work when the 5:24 p.m. crash occurred, Hartman said. Cedar Street is closed from First Avenue to Riverside Avenue as authorities investigate. Hartman said witnesses administered first aid while waiting for police and crews from the Spokane Fire Department to respond. First aid supplies could be seen strewn about in the street among the pedestrian’s personal effects.