The I-17 southbound had been closed at Stoneman Lake Road after what the Arizona Department of Transportation is calling a serious injury crash.
One lane of the area was reopened later Sunday night.
The crash is at milepost 299 and an extended closure is expected.
The original closure has been moved back to milepost 317.
If you are looking for alternatives routes, SR 89A at exit 337 to return to the I-17 is recommended by ADOT for non-commercial vehicles.
Northbound lanes are still open.