Interstate 85 northbound was reopened at 6:30 a.m. after being closed for several hours by debris in the road from a guard rail.

The incident occurred at mile marker 121, north of Hamilton Mill Road.

Several vehicles became entangled in steel cable, part of the guard rail system that runs along the median of the interstate, said Cpl. Edwin Ritter, Gwinnett County police spokesman.

Motorists heading northbound on I-85 are being diverted to I-985 and are asked to avoid the area.

Police on the scene believe the guard rail was damaged by a tractor trailer that left the scene. Several vehicles hit the debris after it was hit by the truck, Ritter said.

There were no injuries.