A shooting on the I-15 southbound collector left one man critically injured and created a traffic nightmare Friday evening.

The Utah Highway Patrol said that at around 5:40 p.m. a man in his early 20s was driving a Jeep Grand Cherokee south on the southbound I-15 connector near the 2100 South exit. Witnesses reported that the man appeared to have been swerving in and out of lanes as some drivers do while text messaging, said Utah Highway Patrol Sgt. Jeff Nigbur.

A dark sports car pulled up to the side of the SUV and there was some sort of verbal argument between the occupants of the vehicles, Nigbur said. At some point, a passenger in the sports car fired a gun at the SUV, striking the driver under his left arm.

"I can't confirm that it was road rage that caused this, but that is what we are being told by witnesses right now," Nigbur said. "Obviously we are looking at all angles, though."

After the SUV was struck, the driver pulled over to the side of the road and someone in the vehicle called 911, the sergeant said.

The driver of the sports car immediately drove away.

An ambulance transported the injured man to Intermountain Medical Center in critical condition. The passenger in the sport utility vehicle, in his late teens, was not injured. Their names have not been released.

Troopers closed the connector from 900 South to 2100 South as they scoured the freeway for evidence. A massive traffic jam followed the shooting.

"Once you get up to speeds of 65 to 70 mph, you can cover a lot of distance in a short period of time," Nigbur said. "So we want to be able to find whatever evidence we can on the freeway. That is why the crime scene is so big."

It was uncertain whether the sports car was a two- or four-door car. Authorities were also unsure how many people were in the car at the time of the shooting. Nigbur said they were actively seeking the people who were responsible.

"We are lucky in the sense that no one else got hurt, but this is unacceptable, and we need to track them down," he said. "We have a lot of officers out working on tips right now."

Anyone with helpful information is encouraged to contact the Utah Highway Patrol at 801-887-3800.

E-mail: ethomas@desnews.com