If you are going northbound you actually have to get in the left lane to get into the rest stop and also to exit.
It is a tricky spot. You have to speed up to get in the left land and they you have to slow down to enter the exit.
The Joisey Turnpike is a very dangerous road, but the Garden State Parkway is even worse. Full of twists and turns, badly designed exits, and crummy drivers.
the rest stop is just north of exit 40 as I recall.
but you are correct, there are cars merging coming out, and others slowing in the left lane getting in. that’s why you can’t blow through there at 90MPH in the left lane, and expect everyone to get out of your way. there are alot of senior citizen drivers in cars down around that AC area, their reaction times are slower.