The Shortcut That Makes Everyone Slower

A new road should make journeys quicker. In this traffic model, it makes every driver’s journey 15 minutes longer. Follow 4,000 drivers through a small network to see why individually sensible route choices can produce a worse result for everyone. We explain Braess’s paradox with original diagrams and a simplified mathematical example. The model: two roads always take 45 minutes; the other two take the number of drivers on that road divided by 100 minutes. Without the connector, a 2,000/2,000 split gives 65-minute journeys. With a directed, zero-minute connector, everyone takes the new route: 40 + 0 + 40 = 80 minutes. Switching back alone takes 85. The result depends on the network and demand. This is not a forecast for every real road project. Moving dots show routes schematically, not individual queue dynamics. CHAPTERS 0:00 The shortcut trap 0:27 The rules 1:10 Before the shortcut 1:52 Open the link 2:32 The individual choice 3:13 Everyone switches 3:57 Why nobody leaves 4:37 The bigger idea SOURCES Easley and Kleinberg — Networks, Crowds, and Markets, Chapter 8: https://www.cs.cornell.edu/home/klein... Braess, Nagurney and Wakolbinger — On a Paradox of Traffic Planning: https://homepage.ruhr-uni-bochum.de/D... Written and animated for Tiny Cause Lab. Narration uses a stock synthetic voice from the open-source Kokoro model. No third-party video footage is used. Small rules. Strange results. #Traffic #Science #BraessParadox