9NEWS viewer Keith Espinoza shot video of the tractor-trailer as it sat on the side of the interstate engulfed in flames.
The driver of the tractor trailer told Thornton police the fire started when his brakes began locking up.
The video shows a small explosion shooting off from the rig before emergency crews arrived and cars cautiously drove by.
Traffic was backed up in both directions.
There were no injuries.
The photos accompanying this story are courtesy of Trevor Kayl.
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