Now grids can’t go on forever (looking at you, Public Land Survey System). They eventually run into geographic constraints: the ocean, rivers, cliffs, etc., or man-made constraints: city walls, railroads, and…highways. See, the big problem I was experiencing is that there are only a few ways across the highway I needed to get over. These bridges become choke points for the thick web of streets on either side. Highways are like rivers: They’re easy to travel down, but hard to cross.