This story has been updated.
Construction on the new Tappan Zee Bridge span is causing lane closures on the northbound side of the existing bridge through Sunday.
Installation of new piles will cause closures of all but one northbound lane heading into Rockland County. Lane closures began 9 p.m. on Friday and will last until 2 p.m. on Saturday, and will be closed again from 9 p.m. on Saturday to 2 p.m. on Sunday.
Motorists heading north can cross the Hudson at the George Washington bridge to the south, or the Bear Mountain Bridge to the north.