The driver, Jason Adams, 33 of Randall Road, may have experienced some type of "medical event" before the crash, police said.
Adams, a driver for Lindy's Taxi in Smithtown, was driving a 2005 Ford cab on Colgate Street shortly before 8 p.m. when he crashed into a car parked in a driveway, police said. The parked car then collided with another vehicle that had been parked in the garage.
Adams was taken John T. Mather Memorial Hospital in Port Jefferson where he was pronounced dead a short time later.
There were no other occupants in the cab. The taxi was impounded for a safety inspection, police said.