CHICAGO (CBS) — A semi-trailer tractor driver has been charged with a Federal Motor Carrier Safety Act violation for unsafe equipment after the brake drum came dislodged from his rear tire, entering the windshield of a driver on I-80 near Joliet. The driver of the vehicle the hub hit was struck and killed, as was her unborn baby.

The victim has been identified as 38-year-old Melinda Cullen from Coal City.

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Illinois State Police said the brake drum jumped I-80’s median near Rowell Avenue.

“I knew it looked bad, I didn’t know the extent of it until later, but my stomach just sank,” said Braidwood resident Rob Bishop.

Cailey Davern, who drove past the accident, said she saw a man running for help, adding he looked panicked.

60-year-old Antanas Sereiva works for EDJ Trucking Inc., which is run out of a residence. No one answered the door when CBS 2’s Dana Kozlov knocked Wednesday afternoon. However, an unidentified man answered the phone, saying, “The truck was in the shop the day before the accident. We are investigating the work that was done.”

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Transportation expert Joe Schweitermann says trucks are supposed to be inspected and certified.

“Of course inspections on tires are a very tricky thing because it’s a very dynamic part of the truck,” Schweitermann said.

Another concern? Road conditions.

“I drive that route all the time, almost every day, and I’ll tell you, that section of I-80 is so outdated — there’s potholes everywhere,” Bishop said.

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Cullen was due to give birth in 10 days; she leaves behind her husband and three young daughters.