I get it now. I misunderstood what you meant. I thought you were saying they need to understand new flows in the existing network better.Whatever data they have is pretty useless in my mind for figuring out how to serve the unserved potential routes/flows best. Naturally they have no current meaningful ticket sales data for service that is currently not available. The absence of circumferential that was mentioned earlier falls in that category. To go from Morristown to Edison you have to cart yourself all the way to Secauscus/New York to change trains to get there. Meanwhile I-287 is completely jammed. And any ticket sales data that NJT may have will show that hardly anyone goes through the pain of using NJT for this journey.
Little circumferential infrastructure exists. That was never the goal as the existing network was built. There are opportunities here and there, though. The median strip of certain highways come to mind. But first, to your point, identifying the specific circumferences that matter most is key. Finding corridors first is the tail wagging the dog until you know where people want to go.