The crash occurred near 356 Route 31 in Raritan Township just after 8:40 a.m., Lt. Scott Nelson said in a press release.
A 62-year-old Flemington man driving a Honda Odyssey southbound went unconscious and swerved into the northbound lane several times, striking two other vehicles before hitting a tractor-trailer, police said.
Responding officers, as well as an off-duty officer from Clinton Township, freed the driver from the Honda and began CPR as the Flemington-Raritan Rescue Squad arrived and took over, eventually resuscitating the man.
The Honda driver had suffered a medical emergency prior to the crash, police said. He was taken to Hunterdon Medical Center for further treatment.
No other injuries were reported.
Other assisting agencies include the Readington Township Police Department,
Quakertown Rescue Squad, Lambertville Rescue Squad, and the New Jersey Department of Transportation.
Click here to follow Daily Voice Garfield-Lodi and receive free news updates.