No serious injuries were reported in either, although the driver in the second rig had to be extricated.
The first occurred near Exit 58 B in Paterson around 9 a.m. Sept. 25.
A witness driving to work on the eastbound side reported seeing the rig in the center lane begin to fishtail to the left.
The driver overcorrected and the rig slammed into the concrete median, the witness said.
It then slid on its side and landed right-side-up, knocking out chunks of the median, he said.
"The car behind me got showered in concrete and blew at least 2 of their tires," the witness said.
An undetermined number of other vehicles apparently were involved, although the extent of damage couldn't immediately be determined.
"That part of 80 near Paterson westbound is like polished concrete," the witness said. "Whenever it's wet there are wrecks there."
Another rig jackknifed on the westbound highway a bit further east in Elmwood Park. Firefighters got the driver out.
New Jersey State Police are investigating both incidents, which each blocked all lanes of traffic at one point and caused massive traffic jams within only a few hours of one another. The second also dumped fuel that needed to be cleaned up.
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