By reducing total travel time and travel distance, taxi ride-sharing is of great significance to decrease urban carbon emissions sourced from ground transport. Heavy computation in matching multiple ride demands has a negative impact in taxi ride-sharing at metropolitan-wide scale. 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,about 6348g CO emissions, 515g NOx emissions, 10g of PM2.5 emissions and 515200g fuel consumption were reduced 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