Nowadays in Buenos Aires, our city of analysis, same as many other cities of developing countries, the transportation system are collapsing. This systems are based on individual mobility, in private vehicles, that are not only unsustainable, but also degrade the environment (regarding visual pollution and noise) and cause congestion that increases air pollution and implies an additional cost to users. From these concerns arises the search of a sustainable, mobility that is friendly with society and the environment alike.
If we understand sustainable mobility as the one which develops from the concern of environmental and social impacts such as air pollution, excessive energy consumption - mainly from non-renewable sources like fuel oil - road congestion, as well as the effects on population’s health, we can be conceptualize it as one that seeks to meet current transportation needs without compromising future ones, dramatically reducing the negative impacts of the current conception. Thus, sustainable mobility has as its ultimate goal the transformation of cities into sustainable entities. These should promote non-motorized transport, especially for short distances, such as cycling and walking. For larger scales, we should be thinking of a multimodal transport system that allows linking high-capacity public transport with non-motorized modes.
Based on the above, in this Lab we continue with the analysis carried out in “Ecobicis” where we studied the flow of bicycles between stations for the community system of the city of Buenos Aires. So, we will focus development on an analysis of trends in supply and demand along with a study of travel times and stations considered to explore the expansion of the existing system by adding new stations.
First, in Figure 1 we observe a trend showing the consistent travel growth in early spring, as a result of temperatures rise, and secondly, an stagnation is appreciated in winter when the opposite conditions take place. Advantageously, the addition of new network nodes anticipate this user behavior by increasing the bike park, preventing the system to saturate, and consequently every year new users are added to the network.
Figure 1A - Evolution of seasonally adjusted trips and incorporation of stations from the beginning Ecobicis system in Buenos Aires.
Figure 1B - Temporal variability of using bicycles system. Historical analysis, monthly, daily and hourly.
However, the question is how intelligent is it to incorporate new stations, and where they should be located. On the above, it is worth mentioning that no-motorized means are usually used, for distances of at most 5 km. Figure 2 and 3 illustrate the above.
On the one hand, you can see how the stations located in the downtown area or near entrances to transport large capacity and long distance, such as railways, are having increased travel, and in turn are often overwhelmed by the demand. On the other hand, on the outskirts of the aforementioned radio, the number of trips drops significantly, indicating that if the prevailing trips are to the center, that is the geographical boundary to expand the network. Then consideration should be given to make multidirectional and decentralized travel with new centers of attraction in the city.
Figure 2 - (Interactive figure) Supply-demand ratio of public bicycles and travel time correlation with frequency of use, according to the seasons.
Figure 3 - Frequency histograms for analysis of travel times and distances traveled.
By testing different configurations of stations of origin and destination in Figure 3, we see that there is a greater tendency to make trips with shorter durations at 20 minutes, which means that this range is the one with higher frequencies. Furthermore, with increasing travel time the frequency of trips decreases dramatically for all source-target configurations. This reinforces the idea that the bicycle is the ideal transport to cover short distances, less than 5 km and therefore to develop a polycentric city environment it is necessary to study traffic flows within the city to expand the network stations outside the radius of 5 km. Figure 4 confirms this and allows us to do a visual analysis of the link between stations and a destination analysis from them.
Figure 4 - (Interactive Figure) Use of bicycles for Ecobicis system Buenos Aires. Season’s analysis.
In conclusion, we can say that the shared bicycle system in large cities is an effective measure to improve the mobility and transportation system generally and to provide the city with complementary tools for the integration of the city in a sustainable way.