The crash happened before 9:00 a.m. just past the Walt Whitman Bridge.
Images from a Sky6 camera near the scene showed all northbound lanes blocked, firefighters on the scene and debris littering the road.
One vehicle was off on the right shoulder and another vehicle in the middle of the highway appeared to have spun around.
There was no immediate word on the number or extent of injures.
Northbound traffic was backed up well past the Broad Street exit as police investigated and crews worked to clear the scene.