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Public transports analysis:
the CityChrone project.
Indaco Biazzo
Politecnico di Torino
SmartData@PoliTO - DISAT
personal page --
citychrone --
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Overspecialization in Science

Very difficult to cross the branches of science.

Slow learning curve

Very difficult to perform self-education path

Science & Research

Multidisciplinary approach

Needs of theoretical framework, instruments and data from various domains.

Complex theorethical and computational tools

Easy to use frameworks, reproducibility of results.


I was born in Rome

I had a very difficult childhood

Rome public transports are
"not so good".
And how much compared to the other cities?

Where is the better served place in the city?
And in the world?

Urban Accessibility Measures

Huge scientific literature
The first definition more than 50 years ago.

Many definitions - low computations
Few attemps to compute it at large scale.

First goal:
to measure the urban accessibility at large scale
Open data

Public Transports Schedules (GTFS format) - transitfeeds

Street graph - OpenStreetMap

Populations data - Eurostat Population Grid, SEDAC

city data and boundary - measuringurban - oecd

Open Source

code generated:

Boundaries and Tessellation
First step towards an accessibility measure:
The larger isochrones are, the faster you move.
Velocity Score
Average velocity taking a random direction
proportional to the number of places reachable in a fixed amount of time

Paris Rome
... ... ...

interactive maps and more cities:
Sociality Score
Number of people is possible to reach in a typical day trip starting from a point.

Paris Rome
... ... ...

interactive maps and more cities:
City Velocity
Velocity Score per person
Inequality distribution of accessibilities
Exponential decay from the center of the city.
Exponential decay of the Velocity Score with the time distance from the center.

Why these patterns are observed in all cities?
Are these inequalities unavoidable?

Can be modified or optimized?
In which way?

I don't known.
Interactive platform

Now I know how much Rome public transports suck

What we have to do to reach Paris?

What are the best interventions given a budget?

Let's Play!
Interactive platform for exploring new scenario
Budget: 5 Bilion €
Name Scenario: Gram Author: Pietro
Useful Links

Interactive platform:

Open Source and Open Data:


theoretical results [arxiv]

Today presentation:



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