Environmental benefits of taxi ride sharing in Beijing.

Although ride sharing as a way to improve transportation efficiency is not new, the scale of ride sharing has historically been limited due to safety concerns and logistics challenges. Recent developments in information and communications technology (ICT) enable real-time sharing of individual geographical information, allow for easier participation in the "sharing economy", and present opportunities for implementing ride sharing at a large-scale. This research aims to quantify the environmental benefits of ride sharing using shared taxis in Beijing as a case study. Trip information extracted from vehicle trajectory data of 12,083 taxis in Beijing are used to evaluate the benefits of ride sharing. Our results show that: 1) only limited opportunity cost to the rider (i.e. tolerance of early departure or delayed arrival) can enable large-scale ride sharing; 2) at a tolerance level of 10 min, ride sharing can reduce fleet vehicle-miles-traveled (VMT) by 33%; and 3) if implemented for the entire taxi fleet, shared taxis can save 28.3 million gallons of gasoline and reduce 186 tons VOC, 199 tons NOx, 53 tons PM 10 , 25 tons PM 2.5 , and 2392 tons CO emissions annually. • Wide adoption of smart phones and apps enable large-scale dynamic ride sharing. • This study quantifies the environmental benefits of taxi ride sharing in Beijing. • If riders can tolerate a travel time change of 10 min, 33% of the VMT can be saved. • Shared taxis can also reduce energy consumption and vehicular air pollution. [ABSTRACT FROM AUTHOR]