Exploring Social Networks as an Infrastructure for Transportation Networks

 

MANUEL CEBRIAN

MIT

 

Data collected from mobile phones has the potential to provide insight both into the relational dynamics of individuals (Eagle et al., Proceedings of the National Academy of Sciences, 106:15274-15278, 2009) and into human mobility patterns (Gonzalez et al., Nature, 453: 779-78, 2008). The high degree of temporal and spatial regularity showed in previous work prompts us to explore the potential of social networks as an infrastructure for transportation networks of small-portable physical goods. We propose an exchange platform where people lend each other objects of small value - such as ski boots or a star-shaped screwdrivers, which are transported by the owners or by carriers (friends or acquaintances of the owner in the social network). Participants in this exchange platform are not required to change their daily routines in order to deliver the items. By running simulations on mobile Call Detail Records - which include location information - from a large metropolitan area, we evaluate the performance of several transportation strategies such as direct transfer, nearest neighbor/only friends, nearest neighbor/everyone, and shortening the distance to the destination, in terms of the percentage of successfully transported objects, time to dispatch, number of hops and traveled distance. For the sake of the simulation we fixed that the delivery of an object was failed if it was still circulating in the network after a month since the injection in the simulation. Results show that completely unoptimized routing heuristics could successfully deliver an average of 3,908 objects --over 10,000 injected objects-- with an average delivery time of 0.59 days. These preliminary results suggest that, under considerably general assumptions, social networks may indeed be an effective and inexpensive infrastructure for transportation networks. This may have two important implications for sustainability. First, a service designed according to this principle might support people in reusing objects and tools that lie unused in one's premises (it was calculated that the average power tool is used 15 minutes in its entire life (Takara, 'In The Bubble', MIT Press, 2005)), therefore reducing the environmental pollution due to the production and transportation of new items. Second, leveraging people's routines to transport items might avoid additional environmental impact due to the transport of the shared items as if they were going to be delivered using a standard service.