There were no deaths, but more than 20 people were taken to hospitals, five of them with serious injuries.
"It was terrible. Everybody started slamming into each other. At one moment, I thought we were going to go over the rail," motorist Joyce Miller told the Houston Chronicle.
The accident occurred around 7:30 a.m. local time, with the wreckage stretching nearly one-half of a mile. The massive pileup happened on both sides of the tollway, which is separated by a concrete wall.
Veronica Valle said the visibility was so poor that her instincts told her to stop.
"All of the sudden, boom, boom, boom," Valle told the newspaper. "I couldn't see nothing -- absolutely nothing -- and that's why I stopped. I smelled burning rubber. I said forget this."
Traffic was stopped for several hours in both directions as emergency workers extinguished fires and took injured motorists to hospitals.
"It looked like a battlefield," said Capt. Ray Valenta with Constable Precinct 5 in Harris County. "It was like something you would see in a movie."