Hudson police were called to Kimball Hill and Clement roads for a report of a collision involving a motorcycle and a vehicle.
A 2008 Ford Explorer being driven by Dante Lonardo, 18, of Hudson, was traveling east on Kimball Hill Road. A 2005 Harley Davidson FLSTF driven by Thomas Ellis, 58, of Billerica, turned from Clement Road onto Kimball Hill Road in front of the Explorer and the two vehicles collided, police said.
Ellis, who was not wearing a helmet, was taken by medical helicopter to Massachusetts General Hospital, police said.
Lonardo was not injured.
The cause of the crash is still under investigation