A 29-year-old man and his 4-year-old son were riding a double bike, crossing the street in the crosswalk. A vehicle approached, saw the two crossing and stopped.
However, a second vehicle behind the first went around the stopped vehicle, hitting the father and son.
The bike was dragged underneath the SUV.
The boy was rushed to Children's Hospital in critical condition having suffered a fractured skull and a broken pelvis.
The father was transported to the Hospital of the University of Pennsylvania with a fractured arm.
The striking vehicle, a Lexus SUV driven by a 40-year-old woman, did stop at the scene. She was visibly shaken as police began their investigaiton.
The driver was interviewed by police and was released. So far, no charges have been filed.
Pedestrians and bikers who use both sides of the highway say the city should take another look at this area. There are pedestrian signs there but no stop signs.
Cars travel at a high rate of speed in both directions.
"It's pretty bad. Every time we come down we have to stop, wait and dodge two lanes of traffic," said Jason Coble of South Philadelphia.
Some say they don't think a stop sign would help, adding the crosswalk, which was just put in last year, is better than nothing.
"I don't think it would cure it because then you'd back up traffic all around the circle and bog everything down. I don't know what the answer is here, but the question is here," said Vaugh Cook of Center City.
For now, police are asking drivers in that area to slow down, and ask pedestrians to keep their eyes open and be careful.