Road Trip Physics

I was driving through a snowstorm yesterday: the dry, powdery kind with 56 km/hr winds sending snow sheeting at right angles across I-80 (and whipping the world into the resemblance of what happens if you drop a cake onto a towel full of powdered sugar when driving into the wind on I-25N).  I really needed an autopilot so I could take video of the interference and turbulence patterns created in the snow streaming across the asphalt by passing trucks: the patterns were much, much clearer than in my lab's ripple tank.  Fluid dynamics are awesome!