Police in Greenwich say the truck was traveling on the northbound Hutchinson River Parkway when it hit the King Street overpass where it transitions onto the Merritt.
The vehicle lost its load of large metal pipes in the accident.
The Merritt was closed at the state line, and the Hutch was closed northbound in the same area on the New York side.
Traffic was detoured through local roads, causing heavy backups in the area.
