Morristown police are advising motorists to avoid the area of Speedwell Avenue and Cory Road, where two vehicles collided at about 4 pm.
The rush-hour crash involved a Toyota SUV and a Plymouth sedan, with possibly serious injuries, Capt. Michael Buckley said.
The state Department of Transportation is assisting police and medical personnel are on the scene, the captain said.
Speedwell is partially closed, and may be entirely closed for awhile, Buckley said. Commuters should avoid the area if they can, he advised.