I thought this was great. I've watched and pondered these things for a while. At some point I want an app to collect GPS data from my phone so that I can try various routes and map out avg speed between home and the office for different strategies.

One thing I've noticed on freeways is that off ramps generate 'waves' because people move from the far left (HOV) lanes to exit, and the right lane gets less dense. Then the following on-ramp has people braking as folks merge on, and as they try to move over to the HOV lane.

It would be awesome if there was some way to have a third dimension, lift up and then exit.