基于时空路径的城市公交时间可靠性研究

时间可靠性是公交重要的时空特性之一,提高公交时间可靠性有助于提高公共交通吸引力。基于时间地理学,从时空过程的角度对公交时间可靠性进行了研究。利用公交时空路径,提出一种城市公交时间可靠性的评价方法,该方法包括单程准时度、单程准时稳定度、站点准时度、站点准时稳定度4个指标。然后利用广州公交GPS数据对各指标进行计算。结果表明,公交时间可靠性随着线路长度增大和站点数增加而降低,随着用地类型的不同而变化,其中商业用地内的时间可靠性最大,并且时段不同,可靠性也有较大差异,其中早高峰的时间可靠性最低,从而验证了所提出评价方法的有效性。

Time Reliability of Urban Public Transportation Using Space-time Path

The time reliability is an important indicator of bus services quality evaluation.The improvement of time reliability has much potential to attract more commuters to public transit and to reduce the congestion through modal shift from cars.The time reliability is one of the space-time characteristics of urban public transportation.At present,there is not much researches on bus service reliability from the time geography perspective.To aim at filling the gap,this article proposes an evaluation approach of time reliability for the urban public transportation in space-time process based on time geography.In this approach,four indexes,one-way punctuality index(OWPI),stability of one-way punctuality index(SOWPI),station punctuality index(SPI),stability of station punctuality index(SSPI),are included.The space-time path,which is a basic concept of time geography,is also used to describe the four indexes as a powerful tool.OWPI and SOWPI are the moderate level indexes to investigate the time reliability of bus line,while SPI and SSPI are the micro indexes for bus stations.In addition,SPI and SSPI are time reliability indexes from the perspective of passengers,and they can also be extended to micro and macro levels.Using GIS and GPS data,space-time paths of buses are formed to calculate the indexes,and 6 bus lines of Guangzhou BRT are given as examples.Moreover,the route length,land use types,period of day and number of stations are considered as influencing factors of time reliability.The relationships between these factors and time reliability are investigated respectively.As to the analysis results,in the same direction of a bus line,the time reliability of bus stations in the upper line is higher than that in downstream.The unreliability accumulation effect can be seen along the bus route.With respect to land use types,a higher reliability in commercial land is indicated,which can be interpreted as that commercial lands,which need better bus service since the commuters in such area,have more time constrains than others.With respect to period of day,the statistical results indicate the lowest reliability is in the morning rush hours since all commuters flock to the transit system at the same time.Meanwhile,a bus line with more bus stations shows lower time reliability as higher stop frequency reduces the arrival accuracy.Recommendations for improving time reliability are proposed in the analysis Recommendations for improving time reliability are proposed in the analysis,which includes rational number(no more than 30) if station of a bus line,and reasonable length of that,and providing better bus services in residential land plus in the morning rush hours.