Quantifying the benefits of vehicle pooling with shareability networks

Abstract

Taxi services are a vital part of urban transportation, and a considerable contributor to traffic congestion and air pollution causing substantial adverse effects on human health. Sharing taxi trips is a possible way of reducing the negative impact of taxi services on cities, but this comes at the expense of passenger discomfort quantifiable in terms of a longer travel time. Due to computational challenges, taxi sharing has traditionally been approached on small scales, such as within airport perimeters, or with dynamical ad hoc heuristics. However, a mathematical framework for the systematic understanding of the tradeoff between collective benefits of sharing and individual passenger discomfort is lacking. Here we introduce the notion of shareability network, which allows us to model the collective benefits of sharing as a function of passenger inconvenience, and to efficiently compute optimal sharing strategies on massive datasets. We apply this framework to a dataset of millions of taxi trips taken in New York City, showing that with increasing but still relatively low passenger discomfort, cumulative trip length can be cut by 40% or more. This benefit comes with reductions in service cost, emissions, and with split fares, hinting toward a wide passenger acceptance of such a shared service. Simulation of a realistic online system demonstrates the feasibility of a shareable taxi service in New York City. Shareability as a function of trip density saturates fast, suggesting effectiveness of the taxi sharing system also in cities with much sparser taxi fleets or when willingness to share is low.carpooling | human mobility | urban computing | maximum matching

Investigating the Potential of Ridesharing to Reduce Vehicle Emissions

“…Another investigation for taxi ridesharing in New York City (Ota, Vo, Silva, & Freire, 2015) identified 46% and 61% savings, respectively, in taxi trips if rides are shared among two and three passengers with nearby trips within 1.6 kilometers. Using the same algorithm for analysis of taxi ridesharing potential proposed by Santi et al (2014), Tachet et al (2017) showed that ridesharing benefits follow the same trends in San Francisco, Vienna and Singapore with total number of taxi trips reduced by 50% for San Francisco and Singapore, and by 42% for Vienna.…”

“…He, Hwang and Li (2014) found that increasing the number of riders to eight per vehicle, by using a mini van, would increase overall travel savings up to 60%. In an investigation for taxi ridesharing in New York City, Santi et al (2014) concluded that, with waiting time not exceeding 5 minutes, ridesharing with two or three passengers could reduce total taxi trips by 50% (reaching full potential in trip reduction) and 60%, respectively. This equates to about a 40% reduction in total taxi trip length.…”

“…This corresponds to the number of recorded trips over a period of time that alternatively affects the potential of ridesharing. Santi et al (2014) studied how the number of shareable trips in a given day varies as a function of the total number of recorded trips. In their study, the average number of daily-recorded trips in New York is around 400,000 and they showed that at approximately 100,000 trips, taxi ridesharing potential reaches its maximum theoretical value.…”

Ordnungspolitik in der digitalen Welt

“…high-speed broadband networks) and can stimulate private investment in the short term" (OECD, 2016, S. 46 Für eine detaillierte Studie der möglichen Verbrauchervorteile durch den Eintritt neuer Anbieter im Markt für urbane Mobilität vgl. , Santi et al (2014) sowie Cramer und Krueger (2014). 25 Das von Kritikern einer Reform der Taxi-Regulierung oft vorgebrachte Argument der Informationsasymmetrie zwischen Fahrern und Fahrgästen (vgl.…”

The smarter, the cleaner? Collaborative footprint: A further look at taxi sharing

“…The excellent paper of Santi et al (2) addresses one of the new forms of consumption that could help in reaching this goal. Santi et al's report shows the feasibility of a shareable taxi service in New York City and its benefits: reduction in cost of service, total travel time, trips, vehicular traffic congestion, and air pollution.…”