Urban densities foster shorter network lengths

One argument for containing urban densities is that cities need a critical population density to sustain sufficiently available public transportation. However, the question of whether denser cities foster shorter public transport networks empirically is problematic, because real-world transport nets are a product of many additional factors that are presumably not related to urban form. I have recently published a paper in which I adopted a network expansion simulation approach to generate and analyze counterfactual data on network lengths for 36 world cities. To do so all networks are generated with similar expansion restrictions and objectives. Denser cities are found to have shorter simulated public transport networks, regardless of the tested model parameters. This provides additional proof that densities are needed to facilitate the provision of proximate public transport infrastructure, with potentially self-reinforcing effects.

The paper is published here. The GeoDMS scripts to generate counterfactual networks can be found on my github.

Transport Link Scanner

It has repeatedly been noted that there is a clear logic behind the geographical expansion of transport networks. That implies that one can model how those transport networks expand geographically; and how the final network would change if the network is constructed with different objectives.

In the last years I have developed the so-called Transport Link Scanner model, which is a GeoDMS based tool that allows the exploration of the effects of economic context and policy preferences on transport network expansion. The model combines a conditional logit model, some heuristics and techniques from the literature on corridor location problems and transport modelling methods to simulate the most likely network after the introduction of a new transport innovation.

The most recent version of Transport Link Scanner can be downloaded through this page. The scripts are downloadable here. The data is available here. Instructions to get you started are available here.