The victim admits he may have cut off another driver at a merge, but the other driver then chased him down and fired a shot that hit him in the back. The wounded driver was able to make his way off the expressway and call police.
The shooting happened shortly after 4 p.m. on Wednesday on I-80/94 between Cline Avenue and Ripley Street.
That wounded driver is expected to survive. He initially thought he'd been hit by a brick or some other object, never dreaming the driver he cut off would pull out a handgun.
The bullet shattered a rear window of the victim's pickup truck before hitting the 48-year-old Valparaiso man in the back.
"You do get a lot of road incidents on the interstate. But it's not common for it to get this far," said Trooper Davonne Barlow, Indiana State Police.
It happened shortly after 4 p.m. Wednesday on eastbound I-80/94 near Lake Station, Indiana.
Trooper Barlow responded to the shooting, which occurred as the victim was driving home from work.
"The victim stated he cut the suspect off. Suspect, the guy, was upset and rolled his window down and, I guess, exchanged words with our victim," said Barlow.
Barlow says the victim sped off, not wanting to engage the middle-age-looking suspect, who was also in a pickup.
But the gunman would eventually catch up, pulling to the passenger side of the victim's truck and firing a single shot.
"He explained to one of our officers that he thought he was hit by a brick at the time of the incident, thought he was hit by a brick or something hard," said Barlow.
The bullet entered the victim's upper back and exited his front shoulder. The slug was eventually recovered in his shirt.
As the gunman exited at Ripley Street, the wounded driver pulled to the shoulder of I-80/94 and called 911.
Police won't say which hospital he was taken to because they don't want the shooter to know the victim's whereabouts.
"He was up and talking, conscious, knew what was going and explained to me the best way he could what happened," said Barlow.
State police have only a vague description of the shooter but say he was driving a silver or grey Dodge Ram 1500 pickup.
Indiana State Police are asking anyone who may have information on this road rage incident or any information on the suspect to please call Detective Mike Bailey at 219-696-0039.