Two people involved in a highway accident in Southbury last night were standing outside of their cars, when another vehicle struck them, one fatally. State Police are investigating the incident that happened westbound by the exit 15 off ramp.  A disabled vehicle was in the left lane when a vehicle came up the same lane and hit the drivers side of the car, which struck a pedestrian.  The driver then hit the other pedestrian.  72-year old Cynthia Northrop of Southbury was transported to Danbury Hospital with suspected serious injuries while 36-year old Michael Canby of Wolcott was pronounced dead at the scene.  37-year old Manuel Melendez did not suffer injuries.  Anyone with information about the accident is asked to contact Trooper Corey at Troop A in Southbury.