Traffic has been backed up on the Garden State Parkway as workers try to make a temporary fix for a sinkhole that blew tires on 18 vehicles.

New Jersey Turnpike Authority spokesman Tom Feeney says the sinkhole was discovered around 6 a.m. Thursday morning on the right lane of the Parkway southbound just north of Route 44 in Woodbridge.

Engineers are trying to figure out the cause. He says possibilities include failure of a nearby culvert or collapsed drainpipes under the road.

He says the two right lanes were expected to be reopened before 5 p.m. Thursday.

A permanent fix is to be made with work at night and on weekends.