CAMBRIDGE (CBS) -- A woman is in extremely critical condition after she was struck by a car in Cambridge Sunday.

The 31-year-old woman, who has not been identified, was crossing Memorial Drive at Magazine Street when she was hit by a BMW around 5 p.m.

The driver, a 56-year-old Boston man, stopped.  The woman was rushed to Beth Israel Deaconess Medical Center in Boston.

The car had a shattered windshield and a smashed side view mirror after the crash.

Marc Heimlich witnessed it.

"There were three people that surrounded her. I think one was giving her mouth-to-mouth and there was another guy that was kind of in the street just trying to tell cars to go single file," he explained to WBZ-TV.

Investigators remained at the scene for hours. The road re-opened about four hours later.

There's no word yet if the driver will face any charges.