The crash happened Monday near the Northern Illinois Academy, a school for people with psychiatric challenges.
An 18-year old girl ran of the building and was sitting in the street.
Theresa Burns tried to get the girl to safety but she was struck by a 1997 Geo Metro car.
The driver left the car and fled the scene on foot, according to police.
"We have no indication the guy was driving erratically, we have no indication he was speeding," Aurora's Director of Public Information Dan Ferrelli said. "Apparently he panicked and he took off."
Police said the girl was not hurt.