Authorities may never know why Avione Jawei Piccard Tolbert chose to park his car near 61st and Broadway before dawn on Sunday, then walk up onto I-135 and cross into traffic.
The 28-year-old Wichita man was hit by a southbound car in the outside lane just after 6 a.m. and killed, the Kansas Highway Patrol reported.
"It appears to us he was walking from the right shoulder to the median," Trooper Aaron McGuire said.
After talking with family members and checking Tolbert's car, McGuire said, "we couldn't really get any specific reason" why he would have walked up on the interstate where he did.
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Nothing suggests Tolbert was suicidal, he said.
It's against the law for pedestrians to walk on or next to an interstate, as signs at exits caution.
Occasionally, McGuire said, motorists make the mistake of walking along the interstate after their vehicle breaks down.
"We have no indication of that" in this case, he said.
"There's no indication that he was either impaired by alcohol or any kind of drugs," though toxicology reports from an autopsy will need to confirm that, McGuire said, and that could take months.
Witnesses said Tolbert also walked into traffic on 61st Street minutes before he was hit on the interstate, McGuire said.
"It might be one of those things that we never know for sure" why Tolbert did what he did, McGuire said.