A woman was fatally struck by a car while she was walking on the Major Deegan Expressway just over the Westchester line.

Police say the woman was struck around 5 a.m. on southbound side of the expressway near 233rd Street by a car driven by a 70-year-old man. The driver stayed on the scene and was not injured.

It is not known why the woman was walking on the expressway.

Two lanes were closed until 10 a.m. as police investigated. Traffic was backed up on I-87 southbound past the tolls in Yonkers, and on the Cross County Parkway throughout the morning rush hour.

All lanes have since reopened.