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.

Using big data to understand mixed use benefits

In the 1960s Jane Jacobs shook urban planning with her famous work ‘The Death and Life of Great American Cities’. If you haven’t read it, give it a try, it’s a must-read! One of the things Jane Jacobs claimed after observing streetlife in her own neighbourhood was that city streets need to be occupied constantly to warrant safety and a pleasant atmosphere in public spaces. She claimed that mixed land-use patterns are necessary to provide constant occupation, and thus that there is a direct link between a city’s physical composition and its social sustainability. Unfortunately, apart from anecdotical evidence, proof from practice for Jacobs’s hypotheses has long been unavailable.

To verify whether land-use mixing indeed affects activity patterns I have recently used a massive dataset of mobile phone usage per antenna in Amsterdam, together with Piet Rietveld, Eric Koomen and Emmanouil Tranos. The used data are recorded by  Dutch mobile phone provider KPN and have kindly been provided by the Dutch ministry of Transportation.

That research proved beyond doubt that, yes, in Amsterdam mixed land-use patterns have more diverse and longer during activity patterns; and that in fact neighbourhoods that have more mixed land uses coincide with neighbourhoods that are more attractive. Thus these findings are, as far as I know, the first ever city-wide proof of Jane Jacobs’s assumptions. A full description of the methods and the results of this analysis have been published in Environment and Planning A. A summary of the research has been published in Rooilijn, a Dutch-language magazine for planning professionals.

For the Environment and Planning A article: click here.

For the Rooilijn article: click here.