Amazingly, except for a cut to the instructor's arm, no one (not even the cars) were hurt. The instructor did have to "sacrifice the plane" to avoid power lines, but he even pulled over to park.

A Cessna single-engine plane carrying an instructor and some students of the Skydive East Coast skydiving school* suffered a mechanical failure at 4,000 feet, forcing the instructor to make an emergency landing on New Jersey's Route 72. No one was injured, aside from a cut to the instructor's arm, and no cars were damaged, although the Cessna did knock down some traffic signs as it landed and parked on the grassy median of the highway.

Sources: | Mashable