Nature Commun. 7, 10793 (2016)

We've all wasted time in a traffic jam imagining there might be a better way to get from A to B. But who among us has actually sat down and done the calculation? Serdar Çolak and colleagues have now provided us with a systematic study showing that traffic congestion can be alleviated, simply by modifying the choice of route. By correlating the road networks of five different cities with mobile phone data, the authors were able to map travel demand with road supply — finding that the ratio could be used to account for the hours lost in congested traffic.

Their proposed strategy for congestion relief involves a centralized routing system that lends credence to the claim that taking the back streets can legitimately relieve traffic flow problems. Optimization techniques for reducing overall congestion could feasibly be incorporated into existing technologies for route finding. The only problem, the authors note, is that individual drivers are likely to find the time savings imperceptible, so choosing the alternative route would really constitute a vote for the common good.