According to police, witnesses said they saw another vehicle stopped in front of Harter's truck and saw Harter arguing with someone outside the vehicles, CNN reported. Police said they believe Harter suffered a single stab wound to the chest, then collapsed in the road's inner median. He was pronounced dead at the scene, the Star reported.
Kerrie Harter said her son never drove faster than 65 mph because he was frugal with his gas money.
"I can only imagine that someone was upset because he wasn't going fast enough," she told the Star. "Is that a reason to take his life?"
Cody Harter was engaged and was one semester shy of receiving a degree in technical engineering from Missouri Western State University.
He also ran his own lawn care business, the Star reported.
Harter was in Lee's Summit to replace a mower that had blown up Friday. The mower was on the bed of his truck before the incident and was found on the shoulder of the highway by police, the Star reported.
"He called me at 7:18 and we had a six-minute conversation," his girlfriend, Shelby Berkemeier told the Star. "Shortly thereafter is when they reported him stabbed."
The man Harter argued with fled north on I-470, according to Sgt. Chris Depue, a spokesman for the Lee's Summit Police Department.
"We think it's truly just one of those stupid incidents of road rage where someone lost their temper and did something really stupid," Depue said.