NORTH HOLLYWOOD, LOS ANGELES (KABC) -- A 21-year-old driver was killed in a collision involving a three-wheeled motorcycle in North Hollywood Thursday afternoon.The crash was reported in the 11900 block of W. Saticoy Street shortly after 3 p.m., police said.Authorities said two Polaris Slingshots were involved in the incident when one of them hit a parked car, sheared a fire hydrant and struck a light pole before it rolled over. The body of the driver, whose name was not released, was seen covered with a red sheet.The second Polaris Slingshot was at the scene of the crash fully intact. Police said the driver of that motorcycle was cooperating in the investigation.It was unclear whether the two were street racing at the time. Authorities were at the scene investigating whether alcohol or speed played a role.Saticoy Street at Gentry Avenue was temporarily shut down but has since reopened.