A collision between a motorcycle and another vehicle closed a section of Middle Country Road in Selden in both directions Wednesday night, Suffolk police said.
The crash took place about 9 p.m., police said, and the roadway remained closed as of 11:05 p.m.
Selden Fire Chief Joseph Leavens said his department's ambulance responded to the scene at Middle Country Road just east of High View Drive at 9:08 p.m., and took the seriously injured motorcyclist to Stony Brook University Hospital.
Leavens said the motorcyclist was conscious and had said he was traveling eastbound on Middle Country road when he struck a vehicle in front of him, and then was apparently struck by another vehicle, Leavens said.
Suffolk police detectives were investigating the accident, Leavens added.