It's a problem that seems really simple until you dig into it. Traffic usually changes, and that's hard to predict. In broad strokes it's a "simple problem" but

It's a problem that seems really simple until you dig into it. Traffic usually changes, and that's hard to predict. In broad strokes it's a "simple problem" but that's true of so many things (from bridges to self-driving cars). The complexity is in handling all the subtleties and edge cases and tuning everything so that the results actually are accurate.