It's amazing how much a little natural geography can completely fuck up traffic. There's a spot in Denver where I-25 shifts slightly, maybe 5 degrees. But I'll be damned if that tiny little change in direction isn't enough to make someone going the speed limit tap their brakes just for a second. Rippled over thousands of cars during rush hour, it creates a bottle neck almost every single day at that exact spot. I'm sure planning an interstate is a nightmare of a task, just knowing that even the slightest deviation from absolutely straight is going to fuck everything up for decades.