That was the original carriageway. Recall that what the Turnpike Authority refers to as the "dual-dual" system (what most drivers refer to as the "car lanes" and the "truck lanes," even though that’s not strictly accurate) used to terminate, or begin, further to the north. When I was a kid that system's southbound end/northbound beginning was just south of Exit 9, which is north of the location seen in those two links. When they extended the system south to just below Exit 8A sometime in the 1980s, they wanted to preserve access to the service area for traffic on either carriageway and so built the flyover ramps; those, in turns resulted in the abandonment of the pavement between those ramps. I assume the reason for doing it that way has to do with right-of-way issues as to what exactly the Turnpike Authority owned (because it’s always easier to proceed within what they have than to go through the eminent domain process).