Publication — The trade-off between directness and coverage in transport network growth
Cities are announcing ambitious bicycle plans. We know where bicycle lanes will be built, but one question remain: in what order should we build them?
This question is what initially motivated my article “The trade-off between directness and coverage in transport network growth”, now published in Applied Network Science.
We systematically study the growth of connected planar networks, quantifying functionality of the growing network structure through coverage (how much of the area the network covers) and directness (how direct routes are in the network). To do so, we study different growth order on synthetic networks mimicking typical urban patterns, starting from the simplest non-trivial structure, the grid.
The results for a grid are shown in the figure below. The general conclusions can seem fairly trivial: random orders are outperformed by greedily optimized orders, that are themselves outperformed by manually crafted orders. But manual orders become unfeasible on larger and more complex networks, making greedy orders a simple and explainable approximation. Additionally, real growth of bicycle lanes can look sometimes closer to a random growth from a network perspective. Considering that ambitious plans can take decades, having an optimal growth order for transport networks could yield significant benefits. A systematic, quantitative method could help in considering trade-offs that are currently implicitly (or even unconsciously) made.
There are plenty of other interesting insights on the properties of network metrics on planar network in there as well, if you want to dig deeper. One of the main reason why this article turned out this way is that I didn’t manage to find what seemed to me “basic” knowledge elsewhere, so I had to make it myself!
This article is a bit special to me, as it is also my first article as a first author. I experienced a lot of frustration, with the project and with myself mostly, but I also learned a lot on how to conduct research.
Thanks to my coauthors Anastassia Vybornova, Ane Rahbek Vierø, Luca Maria Aiello, and Michael Szell for letting me learn from you.