The victim, a 29-year old woman, was struck near the bus stop on Atlantic Avenue near Court Street in the Cobble Hill section just after 12:45 p.m.
Witnesses said the pedestrian was pinned under the car.
She was reported to be unconscious and taken to Lutheran Medical Center in critical condition.
The vehicle came to a rest at the side of a building.
A representative for the cab company, Safari Limo & Car Service, said the car was hit by a truck, which caused the driver to lose control and jump the curb.
The driver was not injured. He had just dropped off a fare and was headed back to base.