One thing Waze will do more than other map applications is direct you to routes that have less traffic. I suspect that after the concert, Waze thought the side street would be faster than the main route West out of the city and to the Atlantic City Expressway. During the day, this should be fine. But after midnight, not good.The same kind of thing happens with other GPS services. I used to need directions to various places on Philly's main line. The routes invariably took me through West Philadelphia. Not all of West Philly is sketchy, but at best it's a depressing drive.
We use Google Maps almost exclusively now, but I have noticed that Google Maps does not do much to redirect us when we are stuck in traffic. Nothing is perfect.
I used to travel up Route 31 years ago when I lived near Trenton and had friends in NW NJ. I liked Route 31. But it is likely more crowded. Personally, I dislike Route 287, but that is my personal preference.