A motorcyclist was seriously injured in an accident in Newtown involving a 17-year old driver.  Newtown Police responded to Berkshire Road near Sherman Street Friday evening.  The motorcyclist, 42-year old Joseph Romeo Jr of Monroe, had been traveling eastbound when a car driven by a 17 year old Sandy Hook girl exited Sherman Street.  The two vehicles collided and Romeo was thrown from the motorcycle.  He was transported to Danbury Hospital for treatment of serious injuries.  The girl was not injured.  Sandy Hook Fire Rescue responded and assisted on scene.  The Newtown Traffic Crash Reconstruction unit responded and is investigating this accident.  Any witnesses are asked to contact the Newtown Police Department at 203-426-5841.