Urban structure has a pivotal impact in residents’ mobility choices. Dense urban structures where diverse functionalities prevail attract more walking and cycling, while longitudinal structures support efficient public transport and therefore transit usage. Low density areas increase the use of the car. The planning community has a good understanding of the underlying theory.
Mobility choices’ impact on urban structure is less discussed however. Empirical studies from Western and Eastern Europe suggest that we are living in a time of hypermobility: in the last 5 decades the number of person kilometres travelled daily has increased drastically. In that same period the number of trips and the overall time spent on mobility have remained constant, suggesting that policies aimed at reducing travel-time often result in land-use changes. The growing land-use demand confirms that travellers chose activities ever further when mobility allows it.
In the upcoming presentation for the Civitas Network Peter will discuss how different transport modes impact the urban structure typology. Car use requires ample space before, during and after usage and therefore their users seek activities in less dense areas, enhancing urban sprawl.
Good quality transit is highly dependent on urban density, however improving suburban services may also lead to a structured urban sprawl (i.e. transport oriented development) due to the limited marginal costs related to travelling one more km by public transport. Unless the pricing policy addresses the issue, the opposite is true: once a traveller has paid for access-i.e. by her time waiting for the service-she is marginally better off with each additional kilometre done.
Cycling (and walking) on the other hand tends to densify urban structures, thanks to energy utility of the users. In other words, they will seek the closest available service since every additional meter must be paid by more energy.
Following this Peter will end the discussion with the description of the integrated bike-transit modality. Due to the fact that access by cycling, as opposed to walking, allows multiplication of passengers to the transit stop, the transit service quality does not require high urban density. However, the concentration of travellers at these transit stops do organically create new points of interest and result in creations of new city centres and sub-centres.
The Dutch are certainly lucky to have developed into such system, their experience should lead with example any megacity across the globe.