AI for Walkable Cities
48 streets: Locate streets to pedestrianize using multiple selection criteria
With the vision of transforming the City of Buenos Aires into a much greener, more serene and more active city, the 48 Streets project was proposed by the French Development Agency (AFD). Four blocks per ood will be pedestrianized to fulfill different improvement criteria across the city.
For each of the 48 neighborhoods of Buenos Aires, a combination of 7 indicators per street segment will be used to take decisions on pedestrianization: number of trees, stores, crime, noise level, corrected compactness, population profile and a novel accessibility metric developed by the ETI Chaire of the University of Paris Panthéon-Sorbonne, directed by Carlos Moreno called the high quality social life indicator.
The high quality of social life indicator (HQSL) requires the analysis of six other parameters: housing choices, modes for commuting to work, where they shop, physical and mental health, access to education and culture, and the use of public space, cross-referenced with 3 urban principles (well-being, sociability, sustainable planet). These indicators are at the heart of the 15 Minute City concept where, within less than fifteen minutes, an urban inhabitant — or within thirty minutes, a territorial inhabitant — can access his essential living needs.
The project was carried out jointly with urbaplan.ch, the ETI Chaire and financed by the AFD (French Development Agency).
Huge data requirements
The initial challenge the project faced was determining the values of each studied indicator, for every street segment. This task is exceedingly intricate for manual execution, prompting the need for a technological solution.
By harnessing these computed indicators and engaging with the community, their primary objective was to identify streets — comprising blocks of 4 to 5 street segments — in each of the 48 neighborhoods that were suitable candidates for pedestrianization. The City sought proposals for four potential pedestrianized streets per neighborhood, carefully assessing which one would yield the most substantial benefits to the local area upon implementation.
Buenos Aires comprises an area of 200 km2 and 30,000 street segments. More than 25 indicators for each street segment had to be computed, resulting in around one million different values that had to be carefully formulated and calculated.
Evaluating accessibility
Ensuring and enhancing citizens’ access to their fundamental needs has become a cornerstone in the strategies of contemporary urban planners. From revitalization initiatives to the development of affordable housing, transit-oriented developments, and the construction of new amenities, accessibility considerations have become a key asset in their decision-making process.
At the forefront of climate change awareness and sustainable development agenda embraced by many major cities lies the imperative to reduce CO2 emissions. Achieving this goal involves actively promoting alternative modes of transportation such as walking, cycling, and public transit. The blueprint for successful emission reduction policies often revolves around the concept of proximity cities, where easy access to essential services is paramount. The development of proximity cities hinges on a thorough analysis of accessibility.
Numerous tools have been created in the last 15 years to compute isochrones and perform static off-line accessibility analysis. However, with the progress of scenario design tools, existent approaches have become obsolete for the lack of dynamism — a modern take on accessibility analysis should allow rapid experimentation which means realtime reachability and travel time computation, both when modifying point of interest dataset and adding new transport routes. Additionally, being able to switch modes and travel times quickly is a big plus for these workflows.
The process of calculating accessibility is intricate and involves a comprehensive understanding of factors such as the street network, the comprehensiveness of transportation infrastructure, including routes and their frequency, bicycle paths, and variations in altitude. With this data, CityCompass™ can compute the time required to traverse the city from one point to another using different modes of transportation, be it walking, cycling, public transit or a combination of them.
How to explore multiple criteria
With all the needed indicators computed, the next question centered around how to combine them in a way that can represent different needs and subjective criteria across neighborhoods. Having flexibility in this point allowed urban professionals from the City to involve the community in the decision-making process, facilitating the future implementation of the project through an active participation.
Different groups among the population had selection criteria as diverse as adding green space, connecting existing commercial corridors, reducing crime, improve road safety or limiting noise. Having a way to measure how all the urban indicators computed will be beneficial for the different alternatives became central to the project.
In order to solve this challenge, a Scoring System was developed, allowing users to weight every indicator to compose a selection that will be in line with their objectives. A slider is provided for each indicator to represent how much it influences the final decision.
As a second step of the workflow, a comprehensive filtering system is provided, that helps identifying the best candidates as we narrow down scores. With this functionality, it is possible, for example, to only select streets without flooding potential, or in a particular percentile in terms of very diverse properties, such as safety, noise levels or tree coverage.
Citizen engagement
In addition to the technical analysis of the indicators, the project methodology included neighborhood walks, talks and workshops with the community. Including the local population in the decision-making process is of vital importance to facilitate its implementation and achieve positive changes. Citizen participation is a strong indicator of the success of public policies, since they are the ones who really know the place where they live.
However, public meetings are chaotic by nature, then having a clear measure that represent different priorities was key to conduct discussions to a productive conclusion. CityCompass™ provided that framework that allowed neighbors to be able to see and compare their subjective perspectives with the methodology indicators and discuss with planners the criteria for street selection.
Conclusions
The pedestrianization of streets is a process that is commonly seen with disapproval by the local residents. They feel uncomfortable not being able to park their cars in front of their houses or to drive on those streets; in the other hand, store owners are afraid of losing customers that arrive by car, among other issues.
The use of CityCompass™ to contrast with the ideas of dissatisfied neighbors and listen to everyone’s opinions made pedestrianization a simpler task. As a result of the project, four streets of between three and five segments each were chosen for each of the forty eight neighborhoods.
By Federico J. Fernandez, Founder & CEO of Urbanly.
