They saw a car driving slowly and erratically on Route 80.
It happened Wednesday night.
The car wouldn't pull over, so the troopers cleared the highway and followed the car into the Town of Mt. Arlington.
That's where the car slowed enough for one of the troopers to jump inside and quickly put it in park.
They say the man was disoriented and had a hard time answering questions.
He's now being evaluated at a hospital.