Authorities said two people were hospitalized with bruises and cuts from broken glass, but except for the shooter no one was shot or seriously injured in the incident Thursday night.
The identity of the man police killed was not immediately released.
"We don't know what ... led up to that," patrol Sgt. Stephen Townsend said Friday. "He didn't know any of those people he rammed. We don't know where he was coming from or where he had been. All of that's still under investigation."
Patrol dispatch received several reports of a man in a white Jeep driving around 100 mph and ramming vehicles about 25 miles west of Green River. The man switched directions several times and tried to hit cars head-on, Townsend said.
The shootout with troopers happened after the man got out and began shooting at people at one of the crash scenes. Townsend said the man ducked behind the Jeep and the troopers were able to get closer to him.
"The individual raised up, raised his weapon as if he were going to fire at them, and that's when the trooper fired," he said.
Sweetwater County Sheriff Dave Gray said two people were hospitalized with minor injuries.
"This was an event that could have hurt anybody," he said. "Just thank God that we didn't have more people injured or more people seriously injured."
Townsend said he would release more information as it became available. He said the Wyoming Division of Criminal Investigation would investigate, which is standard practice with police shootings.