Travel Time Estimation Method Based On Overlapping Of Low Frequency Floating Car Trajectories

"Intelligent Transportation System"(ITS)has become more and more concerned by urban residents with the proposal of "Smart City".Travelers' demand for decision support information in "ITS" is becoming more and more urgent.Travel time is the most important and widely studied parameter describing the operational status of urban road network in “ITS”.It can effectively represent road traffic congestion and be used to evaluate traffic conditions.In recent years,there are many methods for estimating travel time based on GPS data.However,under low-frequency sampling conditions,many algorithms have high estimation errors,and often do not take into account the influence of intersection delays and bottleneck bottleneck on the estimation results.The researches did not consider the link travel time and path travel time together neither.This paper takes low frequency GPS floating car data as the research object,compares the current travel time estimation method,proposes a travel time estimation method based on lap overlapping of floating cars,and also gives the shortest route and fixed point based on the travel time of the road section.Iterative path travel time estimation method.The main research work and innovation are reflected in the following three aspects:(1)Full consideration was given to the various factors affecting the estimation of the travel time of the road section,and the travel time of the road section was estimated using the coupled float vehicle trajectory method.(2)Using the theory of graph theory,Harbin's main roads are divided into various road sections that are more suitable for travel time estimation.The road sections are marked and numbered,and the travel time of a total of 446 major road sections is obtained.(3)Take the travel time of the road section as a basic attribute of the road section into the node map of the Harbin Road network to obtain a weighted directed graph.Use the Dijkstra algorithm to find the travel time of the shortest path of any travel network in the road network,and then use the fixed point iteration The method makes the resulting path travel time more stable and reliable.Based on the trajectory data of the GPS floating vehicle in Harbin,this paper estimates the travel time of all the road sections in the urban road network,and studies the selection of any reasonable travel route and its travel time estimation method.Finally,through the actual data,the proposed technical methods were verified.The results show that compared with the travel time of a specific section,the impact of intersection delays on the travel time of the link is taken into account,and the actual travel time of the actual link is obtained.The travel time based on the travel time of the link is directly accumulated and calculated.Compared with the method,the path travel time estimation method proposed in this paper not only effectively improves the estimation accuracy of the path travel time,but also satisfies the demand for travel path selection.The research results of this paper can provide strong technical support for ITS travel information services,and can also provide certain theoretical and reference values for the dynamic management of urban road traffic.