Study On The Influence Of Rainfall On Traffic Travel Based On Taxi Trajectory Data

The amount of motor vehicle ownership has increased rapidly in the past ten years,which makes the contradiction between supply and demand of urban transportation system become more and more prominent.In the mega-cities,traffic congestion is becoming normal.Rainy weather make the road slippery,reduce the road adhesion coefficient and affect the driver’s visual field,which will make people’s travel experience worse.It’s significant of studying the impact of rainfall on traffic travel,providing a theory evidence for managers to develop scientific and effective traffic management measures and emergency plans.The popularization and development of taxi GPS system provides a new method that we can get the traffic information more simple and comprehensive.This paper studies the effect of rainfall on traffic travel based on the meteorological data and taxi GPS data of November 2012.The study mainly divided into three parts.First,we extract the OD from the travel trajectory data and study the influence of rainfall on the number of travel and the distribution of OD.The application of map matching results will make the result is not only visible,but also can be matched to the actual point of the map.Second,with the expressway,trunk road and secondary trunk road as the object of the research,the matching sample T test method was used to study the influence of rainfall on the average velocity of road sections and the free flow velocity of road sections.At the same time,using the velocity information from trajectory to study the effect of rainfall on velocity distribution in space.Third,taking Beijing West Railway Station,Beijing South Railway Station and Beijing Railway Station as the research object,the influence of rainfall on the congestion of large traffic hub was studied by spatial autocorrelation analysis.This study results show:The effect of rainfall on number of OD is related to the rainfall and whether workdays or not.Under non rainfall conditions,the most densely distributed regions of OD are concentrated in the third ring,and under the condition of rainfall,the regions are concentrated in the major transportation hub.Traffic management should pay more attention to the Beijing West Railway Station,Beijing South Railway Station,Beijing Railway Station,Beijing International Airport,Wukesong subway station and the intersection of Workers Stadium North Road and Sanlitun Road to ensure the residents’ travel demand through taxi scheduling.Under the condition of rainfall,the free flow speed reduction ratio of expressway road is about 3%-3.5%and is about 6.5%-7%of main road;the average speed reduction tatio of expressway is about 3%-3.5%under the condition of light rain and can reach 7%-7.5%when the rain is heavy.The influence of rainfall on the north-south direction of the loop road is greater than that of the East-West Road and the influence degree of the second ring and third ring is greater than that of the Fourth Ring.The airport expressway,Jingshi Expressway,Landianchang North Road and Xizhimen North Street are affected by rainfall most so that we can avoid these roads when it’s rainy.The congestion is easily happened around the large traffic hub,we should pay more attention to the road traffic around the hub in the rainy days.It is of some significance to study the effect of rainfall on the traffic travel based on the taxi trajectory data.In the follow-up study,we can continue to perfect the research on this basis.