Opinion

Mobility policy needs systems thinking

Arie Bleijenberg — September 3, 2024

System thinking is badly needed in mobility policy. The Covid-pandemic – undesired and unpleasant – provided two illustrations.

The famous 1972-study The Limits to Growth for the Club of Rome, was based on systemcanalysis. Modelling negative feedback loops from environmental degradation, resulted in a gloomy global outlook for prosperity, food production and economic growth. The warnings from this MIT-research have not been followed up by adequate policies, because the real-world developments until now are roughly in line with the scenarios made half a century ago (see Update to limits to growth - Comparing the World3 model with empirical data). System thinking is a powerful tool to look forward, to be aware of unexpected outcomes and to identify effective leverage points for change.

System thinking is badly needed in mobility policy. The Covid-pandemic – undesired and unpleasant – provided two illustrations. One was directly after the first severe lockdown. At first public transport use decreased by three quarters and highway traffic by fifteen percent (Dutch data). However, within a few weeks, people noticed that highway congestion had disappeared. This increased car driving, partly resulting in even less use of public transport. These dynamics show that highway congestion is an equilibrium, with a direct impact on mobility behaviour. Too much congestion incentivises car drivers to travel outside rush hours, to choose a nearby destination, to drive together or to shift to public transport. Too little congestion has the opposite effect, as experienced during the lockdown. These system dynamics explain why road congestion cannot be solved, resulting in The Fundamental Law of Road Congestion.

The second example is the boost in working from home, caused by the pandemic. It is expected that working at distance will remain double the level from before the pandemic. Did this result in the hoped for reduction in congestion and pollution? Two studies in the field of labour economics indicate that the answer is no. “Working from home increases work-home distance” is the title and main conclusion from a German study. After the pandemic, new jobs are on average further away from home, than before. Also, people accept on average a longer home-work distance when they choose a new place to live. A Dutch study points in the same direction. People who never work from home have an average commuting time of 25 minutes, while people who partly work from home travel 40 minutes a day one-way. The aggregate commuting time per week is roughly the same for both groups. So, travelling fewer days to work, doesn’t result in less mobility, because it is compensated by longer home-work distances.

A popular statement in mobility policy is that people want to travel from A to B. However, this linear thinking violates the working of the complex system of land use and mobility. Two crucial characteristics of this system were illuminated by the Covid-pandemic. Total travel time per person is on average roughly constant. And faster travel results in longer travel distances, instead of in time savings. This is further elaborated in my paper The transport-urbanisation dialectic.


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