Houston police said four vehicles, including an 18-wheeler, were involved in a wreck in the westbound lanes of the Northwest Freeway near 43rd.
All westbound lanes were closed while police investigated and crews cleared the wreckage.
Traffic was backed up for several miles. Some drivers used the entrance ramps as exits.
All lanes of the freeway have reopened, but traffic was slow for a while.
No injuries were reported.
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