One of the latest videos (23 minutes) from jarret Walker, on the importance of geomtry and how it affects predictions.
"Transportation planning seems, at times, to be all about prediction. Consultants vie to do the best models. Journalists do gotcha stories about whether predictions were right. Competing predictions confuse local elected officials and activists. Jarrett Walker explores how much prediction we really need, and how our longing to know the future may interfere with our ability to have clear conversations. While the focus here in on transit, the insights may be useful to people in all aspects of planning"
Watch the video on Youtube: https://www.youtube.com/watch?v=3x3yure0Qko