MEAD, Colo. (KDVR) — A deadly crash had Interstate 25 closed for much of Monday night between Denver and Fort Collins, at the Mead exit in Weld County.

Megan Arneson, 32, of Loveland was killed when a big rig hauling a piece of construction equipment hit an overpass, causing major damage and leading to the crash.

John Morgan and Sarah Blair tell FOX31 they were on the interstate right by Arneson when the truck crashed into the bridge.

“We saw a big plume. It looked like dust, like just a huge cloud of dust,” Blair said. “And then suddenly, it looked like she had just careened off the road really quickly.”

Blair said she noticed that a woman in the driver’s seat of the white car did not look OK.

“We just ran out of the car and ran towards the SUV and that’s when we saw the child in the back climbing to the front seat to get his mom’s phone,” Blair said. “And we just realized that he should not be in the car.”

Blair and Mortan said they took the 10-year-old boy out of the crashed car and brought him to sit inside theirs with their children until medics could make it to the scene.

“He started naming his address and his mom’s name and her age, all the information you teach your kids, like here’s what you’re saying in an emergency,” Blair said. “And then he just he was like, ‘A brick came through the windshield and my mom couldn’t see.’”

“He just kept asking my kids, ‘Is my mom going to be OK? Why aren’t they taking her out of the car?'” Blair said.

According to Colorado State Patrol, Arneson died at the scene. Officials said her white SUV was behind a semi truck hauling a track hoe. The track hoe had its arm up and crashed into the bridge and sent concrete right into Arneson’s windshield.

Officials said the truck driver pulled over and stayed on the scene. There have been no charges filed at this time. The investigation is still ongoing.

A friend of Arneson told FOX31 she was a single mother and her son was her world. Loved ones have set up a GoFundMe account to help her family after the tragedy.