The above procedure is used to interpolate trips from a given sample in a static manner in time. We have extended the method of ref. Algorithm 1 see Supplementary Information , Algorithm S1 exploits the exponential nature of inter-events times between trips see Supplementary Information , Fig. S5 coupled with the statistics of daily and hourly trip generation see Supplementary Information , Fig.
Finally, for each intersection, the number of allocated trips is distributed in time according to a Poisson process. The code for this extension was made public How to cite this article : Tachet, R. Scaling Law of Urban Ride Sharing. Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
The datasets used for this study have been obtained from different sources. The Vienna taxi dataset has been obtained by AIT and Taxi , while the Singapore taxi dataset has been obtained from the Singaporean government. Samples of the two latter dataset will be made available upon request. Tachet, P. Santi, and C. Research of S. The authors declare no competing financial interests. Author Contributions R. S contributed to the dimensional analysis and writing. National Center for Biotechnology Information , U.
- Scaling Law of Urban Ride Sharing.
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Sci Rep. Published online Mar 6. Tachet , a, 1 O. Sagarra , 1, 2, 3 P. Santi , 1, 4 G. Resta , 4 M. Szell , 1, 5 S. Strogatz , 6 and C. Ratti 1. Author information Article notes Copyright and License information Disclaimer. Received Oct 31; Accepted Jan This work is licensed under a Creative Commons Attribution 4. This article has been cited by other articles in PMC. Abstract Sharing rides could drastically improve the efficiency of car and taxi transportation.
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Open in a separate window. Figure 1. Shareability curves. Figure 2. Shareability law. Discussion Our main contribution is the discovery of a unifying mathematical law that governs the potential for ride sharing in cities of diverse sizes and traffic characteristics. Table 1 City Parameters. Table 2 Shareability in different world cities. Additional Information How to cite this article : Tachet, R. Supplementary Material Supplementary Information: Click here to view. Acknowledgments The datasets used for this study have been obtained from different sources.
Footnotes The authors declare no competing financial interests. References Mumford L. Size, sprawl, speed and the efficiency of cities. Urban Studies 36 , — Arnott R.
Reinventing the Automobile: Personal Urban Mobility for the 21st Century MIT Press
Roads and parking spaces limit the possibility of dense, walkable development.
What's needed is a reimagined urban transportation system that increases quality of life while reducing pollution, noise, and lost productivity. Reinventing the Automobile proposes such a system, step by meticulously described step. Because it will be electric -- run, like laptop computers, on lithium ion batteries -- it will be simpler and more modular than cars with internal combustion engines: "A traditional car requires elaborate systems of reservoirs, tubes, valves, and pumps to distribute the gasoline, oil, water, air, and exhaust gases, but a battery-electric automobile replaces most of these complicated distribution systems with wires connecting the batteries to the wheels.
The motors that power the car will be in individual wheels, attached to a "skateboard" that carries the batteries. Wheels can be attached in virtually any configuration -- traditional four-wheel rectangle, four-wheel diamond, six-wheel, even two-wheel balanced, like the Segway, by a gyroscope. Similarly, the skateboard design allows for virtually any shape or design of chassis, enabling any kind of seating posture and any driving interface.
The hegemony of steering-wheel-and-two-pedals will end at last. USVs will be equipped with an array of sensors and controllers that enable them to maintain steady distances from other cars, avoid crashes, and even pilot themselves. Yes, pilot themselves. The authors drop this notion into the mix rather casually, but it's the first real signal that things are going to get Jetsons--style crazy here.
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Far more than any advanced engine or materials ever could, this situational awareness will allow the vehicles to be smaller, lighter, less armored, and more energy efficient. At least initially, they'll need to travel in dedicated lanes so as not to wind up smeared on the bumpers of SUVs. Where the vision tips over from cool-for-car-nerds into mind-blowing is not in the car itself but in how it's connected to the power grid, other cars, and the city around it. Most cars are parked about 95 percent of the time.
All those idle batteries add up to considerable energy-storage capacity. Having a place to store electricity is important because America's power system, like its cars and parking infrastructure, is overbuilt, scaled to meet peak demand. With a place to store surplus electricity when it's made and release it when it's needed, system engineers can "shave the peak. The authors envision USVs converging with other technologies -- rooftop solar panels, small wind turbines, geothermal heat pumps, cogeneration systems, large-scale batteries, smart grids -- to create a new kind of power system in which cities are generating, managing, and distributing all or most of their own electricity.
This kind of local, distributed power system will eliminate the high cost of transmission lines bringing power from a distance, reduce smog and other particulate pollution, eliminate dependence on foreign energy, and, at the limit, make possible carbon-neutral cities.
Think of the location--specific services an iPhone offers, from maps and directions to restaurant suggestions to hyper-local news. Now imagine a similar range of apps for a vehicle that's receiving real-time information about road congestion, parking availability, and the latest box scores. Imagine the benefit to traffic planners of having information about the location and trajectory of every vehicle encrypted, say the authors, but their discussion of privacy issues is cursory at best. This "Mobility Internet" could lead to the same kind of innovation unleashed by the Internet itself.
Among other things, it could enable a revolution in civic management of road, parking, and power services. Currently the large majority of roads and a great deal of parking is free, and as any economist will tell you, an unpriced resource will be overused. Sure enough, road and parking demand frequently exceed supply, leading to congestion, a good chunk of which, Traffic reminds us, is created by people driving around looking for parking "parking foreplay" also causes one in five urban collisions.
Although power isn't free, it's generally sold at a flat rate, leaving consumers no way of knowing when it's most valuable. Toll roads and congestion charges are crude attempts to change the situation. Once the devices that consume road, parking, and power services are connected to the Internet, however, cities can institute variable, real-time, citywide pricing for those resources, based on the balance of supply and demand moment to moment.
This could radically increase the productivity of resource use, compensating at least in part for the expense of building these systems. Cities would become more like organisms, their subsystems controlled and coordinated by a unified nervous system.