By reducing total travel time and travel distance, taxi ride-sharing is of great significance to decrease urban carbon emissions sourced from ground transport. Efficiency of taxi ride-sharing at metropolitan-wide scale can be challenged by heavy computation in matching multiple ride demands in. In this paper, a fast matching strategy based on time and distance constraints is proposed to filter candidates. Experiment shows that the strategy can reduce the times of candidate matching and improve the searching efficiency. An empirical analysis of potential taxi ride-sharing in two periods of a day (9:00-10:00,21:00-22:00) based on taxi GPS trajectory data in Qingdao shows that when tolerance time of delay time is 5 min, 35% of the total trips can be shared. Total travel time of all trips can be saved by nearly 222 hours and the total travel distance can be reduced by nearly 9200 km. CO, NOx, PM2.5 and fuel consumption can be saved about 6348g, 515g, 10g and 515.2kg during each period, respectively. Our study provides a positive evidence for potential emissions reduction by taxi ride-sharing, so as to support better understanding on low-carbon urban transport service.
Keywords Taxi GPS trajectory,taxi ride-sharing; matching and filtering strategy