Would you open the shortcut?
Individual route choices can make a new connection harmful at equilibrium.
Inside this model
In the classic four-node toy network, two outer links each cost flow/100 minutes, two fixed links each cost 45 minutes, and the shortcut costs zero. Route flows are solved by enumerating symmetric equilibrium choices. The chart compares equilibrium travel time with and without the shortcut over demand.
Out in the world
A practical use
Road planners can test whether a new link changes route incentives rather than only adding capacity.
A useful lens. Not a universal law.
- The model assumes identical travelers and deterministic travel-time functions; real road networks require calibration.
Associated thinkers
Further reading
Explore the original research or the teaching reference behind this experiment.
Dietrich Braess — On a Paradox of Traffic Planning ↗