The rig hit the metal railing on the highway's eastbound side just off Main Street shortly after 1:30 a.m. Thursday, March 30, Police Chief Michael Walker said.
The driver was initially tended to by borough police and firefighters from River Edge and Hackensack.
He was then taken to Hackensack University Medical Center with injuries that the chief said weren't considered life-threatening.
A heavy-duty wrecker from Brookside Towing removed the rig, which apparently had been leased out of Middlesex County.
The exit was obviously closed, and a single lane of Route 4 remained open for a good deal of the time.
The roadway was completely reopened around 4:30 a.m., three hours or so after the crash.
The cause of the crash was being investigated.
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