It happened at 7:30 p.m. Thursday on 5th Street near Hunting Park Avenue in the city's Hunting Park neighborhood.
The incident was all captured on a dashcam video by a motorist that showed almost 100 ATV's and dirt bikes driving northbound on 5th Street.
Moments later, police say one of the ATV's occupied by two males ran a red light and was struck by a white Chevy Tahoe traveling west on Hunting Park.
"The front of that vehicle struck the ATV and dragged it about 50 feet in a west bound direction. And threw both of the males that were on the ATV off the vehicle where we found them in the 500 block of Hunting Park," said Police Chief Inspector Scott Small of the Philadelphia Police Department.
The impact severely injured the 23-year-old and 18-year-old men riding on the ATV.
Officials say one of the victims may lose both of his legs while the other could lose one leg.
Both victims were rushed by paramedics to Temple University Hospital and remain in critical condition.
Police say young people riding around on ATV's and dirt bikes across the city continues to be a major problem.
"It's not street legal, there's no license plate, it's not registered, no turn signals, and they were driving north on 5th Street with a group of other ATV's and other dirt bikes," said Small.
Video of the accident has been making its rounds among other ATV riders in the community.
"I pray for the guys. I hope their families are keeping strong," said an ATV driver named Jay.
He says the accident has struck a nerve with ATV and dirt bike riders.
"People still are going to ride. Just now, people are going to be extra cautious knowing that something just finished happening like that," he said.
Jay admits that a lot of people riding ATV's and dirt bikes on the streets of Philadelphia do so recklessly, putting themselves and others at risk.
"Like I said, not all of us drive stupid. Some people just love doing tricks, but some see it as doing it recklessly," said Jay.
He says some of them prefer to drive around in vacant parking lots, but eventually cops move in.
So far, no charges have been filed against the driver of the SUV.
But charges are pending against the driver of the ATV.
No other injuries were reported.