Officials told Channel 9 a BMW slammed into the back of the big rig at a high rate of speed around 1:45 a.m. on I-77 near Clanton Road and became pinned under it.
All three people killed were in the BMW, according to troopers.
The victims have been identified as Alcides Adan Arias Diaz, 25, Keneth Romero Tzul, 30, and Lelis Baltazar, 37.
Nobody in the tractor-trailer was hurt.
Investigators said the BMW was traveling at speeds in excess of 100 mph but were not sure if alcohol played a role. Troopers did tell Channel 9 that it appeared weather was not a contributing factor.
Officials said the driver of the tractor-trailer felt something but thought it may have been a flat tire and ended up dragging the BMW more than 1,500 feet before stopping. Crews had to use a crane to lift the tractor-trailer off the BMW.
All lanes of the interstate were reopened just before 5:30 a.m.
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