A Dallas police officer was injured in a crash on Interstate 635 involving an overturned 18-wheeler Thursday night.
The big rig apparently rear-ended the officer's squad car on westbound Interstate 635 just west of Preston Road.
The 18-wheeler overturned, but the driver was not injured.
The officer was taken to Baylor Medical Center with minor injures as precaution.
The right two lanes of Interstate 635 were blocked, snarling traffic. A Dallas Fire-Rescue hazmat team was cleaning up a fuel spill from the overturned truck.
Authorities said the wreck should be cleaned up long before the morning commute.
NBC 5's Scott Gordon contributed to this report.