The accident happened at Cary Avenue and Elizabeth Street in West Brighton.
Brian McGurk, 40, turned himself in to police shortly after the accident. He now faces charges of leaving the scene of an accident.
"The lady was on the floor, everybody was there screaming," witness Gustavo Sierie said.
The 56-year-old grandmother, identified as Clira Almaco, was struck and killed after she pushed her young grandson out of the path of the oncoming car.
A moment later, Almaco was sprawled on the road, critically injured as that driver sped away.
She was rushed from the scene, but doctors at Richmond University Medical Center could not save her. Witnesses say the impact threw her 10 to 20 feet in the air.
"I seen the lady on the floor, with her hair on the floor, and she looked knocked out," Sierie said. "And the boy, right here on the corner, he was just shaking, sitting on the floor, look traumatized."
The boy's injuries were said to be not serious. His grandmother's quick move had saved him.
Almazo was the mother of six who lived nearby on Elizabeth Street.
Her death has shaken neighbors.
"Everybody on this block is like family," neighbor Deirdre Qinn said. "Just like family. Anything that happens, we get together and console each other."
Police say more charges could be coming against the driver.
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