London Underground trains could be travelling too quickly, causing more congestion, according to a new study.
An international team of researchers mapped the rail networks of London and New York using geographical and topological data from open and governmental sources, and measured the average speeds at which the rail networks functioned most efficiently.
They found that the speed of Tube trains could be leading to an increase in the overall level of congestion, whereas New York only benefitted from faster trains.
The reason for London's need for slower trains is that bottlenecking occurs at key stations outside the city centre where people switch transport modes, eventually causing inefficiency in the rail network.
The mathematical study, published in the Royal Society Interface journal, calculates that London’s system would function most efficiently with trains running at an average of 13 mph. The current average speed of Tube trains is 21 mph.
The study concluded that:
Even if these studies are still very theoretical, they show convincingly that reasoning with only one transportation mode can be extremely misleading, and that policymakers cannot limit themselves to a single aspect of an urban system without risking making decisions that are locally correct but globally wrong.