DENVER (KUSA) -- Just minutes after kissing her great niece and great nephew goodbye Monday morning, Betsy Hinkle got the shock of her life.
"I just turned to the television screen and I gasped, 'oh my God that's my niece's vehicle.' She was just here," Hinkle said.
Shortly after leaving Hinkle's house in Arvada, Hinkle's niece Kate was driving down Interstate 25 with her 10-year-old son and 5-year-old daughter in the backseat.
Kate's cousin, 26-year-old Brandon, was in the passenger seat.
"All of a sudden, loud noise, crash, and he had concrete in his lap," Hinkle said.
A semi driver for RMS Cranes clipped the Speer Boulevard overpass with his trailer.
Denver police cited the truck driver for careless driving, for ignoring signs telling trucks to move to the inner lanes.
The inner lanes of the Speer overpass clear 16-feet 8-inches, which is more than high enough for the truck involved in the accident, which had a height of 14-feet 4-inches.
The outer lanes are just 13-feet, so when the semi stayed in the far left lane the top of its trailer struck the overpass sending chunks of concrete and metal flying into Kate's car.
"Her head was to the side and [Brandon] saw blood," Hinkle said.
A chunk of concrete smashed through the windshield, knocking Kate unconscious.
"So he pulled the emergency brake," Hinkle said.
The car was still traveling at highway speeds and beginning to lose control.
"They were headed towards the K rail in the middle of I-25, so he had to grab the steering wheel to steer them away. He kind of said he had the feeling that the vehicle may flip over," Hinkle said.
With the two young children in back, Brandon guided the car to safety.
"He's a hero," Hinkle said.
Aside from a few cuts and bruises, Brandon and the kids are okay.
"Kate does have a head injury. She's kind of banged up and sore," Hinkle said.
Kate was released from the hospital shortly before 7 p.m. Tuesday.
Hinkle says hospital tests show Kate doesn't have any brain damage and doctors say she'll make a full recovery.
"It could have been so much worse," Hinkle said. "It's just amazing how, after seeing that vehicle, that nothing worse happened."
Will Ripley, KUSA