A New York State Department of Transportation worker has been struck by a car on Interstate-684.  State Police say a driver headed northbound in Southeast, a mile north of the rest area, hit the worker Monday afternoon.  Troopers responded and determined that 48-year old Richard Russo of North Salem was driving a Chevy Silverado in the right lane at the time of the accident.  The road worker, identified as 41-year old John Fitzpatrick of the Bronx, was airlifted to Westchester Medical Center with serious but believed to be non-life-threatening injuries.  684 was partially closed northbound until shortly after 8pm.  This investigation remains on-going.