The headache-causing steel plates on the Westchester-bound lanes of the Tappan Zee bridge are being moved to the northbound side.

The thick, temporary plates were placed as the Thruway Authority replaced the bridge's expansion joints. The southbound work will be completed Friday evening. The plates will be relocated so work can be finished in the other direction.

The work is only a temporary fix until a new bridge can be built.

Commuters experiencing backed-up traffic in the morning may have to expect similar traffic on their return trips.

The Thruway Authority anticipates the plates will only be needed on the northbound side until Dec. 8. They say construction will continue, but the plates will no longer be needed.