Washington ? Neighbors and rescue personnel threw children out of the path of a speeding car that plowed through a crowded street festival, preventing more serious injuries than the 40 people struck, Mayor Adrian M. Fenty said Sunday.

A 4-year-old boy with a broken leg was the only person still hospitalized a day after a woman’s car sent people and strollers flying, leaving debris and injured bodies strewn in her wake.

“I can’t believe that we’re actually saying that, right now, everyone is going to pull through,” Fenty said. He credited “some unbelievable heroism” by citizens and rescuers.

Authorities believe the driver, Tonya Bell of Oxon Hill, Md., was going about 70 mph when she tore through Unifest, a church-sponsored street festival in southeast Washington.

Bell was treated for an ankle injury and was in police custody pending arraignment today, police said. She was preliminarily charged with aggravated assault while armed. The “armed” designation is because she used a vehicle.

Marcellus Jackson’s father saved the boy’s life by throwing him out of the way of the speeding car, Fenty said. The father, Vincent Hayes, was then hit by the speeding car head-on but was OK.

Bell had a 7-year-old girl in the car with her whose identity wasn’t released. The child was not injured and was taken by Child Protective Services.