A 22-year-old woman was fatally struck by a runaway taxi on a Midtown sidewalk last week, after the driver parked and stepped out to assist his passenger. The NYPD confirmed only that the driver “parked” his taxi, and investigators are still trying to determine what caused the vehicle to roll, driverless, onto the adjacent sidewalk.

The vehicle plowed through the sidewalk and struck Suhuyn Park and a 21-year-old male pedestrian. Park, from South Korea, succumbed to her injuries at New York Presbyterian on Monday.

The 67-year-old driver, whose name has not been released, parked his 2012 Toyota taxi near the corner of West 51st Street and Eighth Avenue around 8:30 p.m. on Wednesday December 30th, according to the NYPD. He was helping his passenger out of the taxi when it began rolling onto the sidewalk, striking Park and the second pedestrian before hitting the back of another cab at the intersection of 51st Street and Eighth Avenue and coming to a halt.

EMS on the scene transported both victims to New York Presbyterian. Park was initially listed in critical condition. The male pedestrian suffered only minor injuries and has since been released.

The driver remained on the scene, and no arrests have been made. An investigation by the NYPD's Collision Squad is ongoing.

Traffic deaths decreased in New York City in 2015. The Department of Transportation says that 230 people died in crashes last year, down from 257 in 2014, and 297 in 2013.