Sofia Traffic Jams Solution
You know the saying, when in a traffic jam ask a mathematician for help. Well, in a few hours I will be heading to the ghastly Bulgarian capital and I already dread the time it will take me to get in and out. As faith would have it, there is a perfect solution which requires the usual large scale mismanagement of the city and some luck. Here is the wikipedia article for the Braess’s paradox.
Braess’s paradox, credited to the mathematician Dietrich Braess, states that adding extra capacity to a network, when the moving entities selfishly choose their route, can in some cases reduce overall performance. This is because the equilibrium of such a system is not necessarily optimal.
The paradox is stated as follows: “For each point of a road network, let there be given the number of cars starting from it, and the destination of the cars. Under these conditions one wishes to estimate the distribution of traffic flow. Whether one street is preferable to another depends not only on the quality of the road, but also on the density of the flow. If every driver takes the path that looks most favorable to him, the resultant running times need not be minimal. Furthermore, it is indicated by an example that an extension of the road network may cause a redistribution of the traffic that results in longer individual running times.”
This runs the other way as well - unwitting removals of extra routes sometimes lead to overall decrease in travel time. So Sofia, feel lucky the next time your mayor shuts down several major boulevards. In any case, the road renovation works in the capital from last summer make me appreciate Blagoevgrad all the more.
