Mahwah police temporarily closed the highway in both directions following the crash where Route 17 meets Route 287 at the Mountainside Avenue overpass around 12:30 a.m. July 25.
The collision with the metal signpost "opened nearly the entire side of the trailer and sent debris across all lanes, both north and south," Mahwah Police Chief Timothy O'Hara said.
"The driver was initially trapped but freed himself and walked away unscathed," the chief said.
"Amazingly, no other vehicles were involved nor was there anyone hurt in this incident," he added.
Front loaders were needed to offload the trailer's contents. Diesel fuel runoff also had to be cleaned up.
All lanes were reopened by 6 a.m., O'Hara said.
Responders included Mahwah police and firefighters, Ramsey Rescue members, New Jersey State Police, the state Department of Transportation, a Bergen County Hazardous Materials Unit and the state Department of Environmental Protection, the chief said.
An investigation was continuing, he said.
Kyle Mazza/UNF News took the photos and contributed to this story.
Click here to follow Daily Voice Ridgewood and receive free news updates.