Box truck overturns on I-540, causes lengthy backup

RALEIGH, N.C. (WTVD) -- A box truck flipped over on Interstate 540 westbound just before 9 a.m.

Chopper 11 flew over the crash site on I-540 near exit 1, which is the exit for I-40.

Crews were cleaning up the crash and had all but one lane closed.

The backup on the main thoroughfare stretched more than half a mile.

NCDOT estimated the crash could take until 12 p.m. to clear.

There's no word yet on what caused the crash.