Study On The Reliability Of Urban Traffic Path Based On Time-varying Characteristics

With the rapid development of cities,traffic congestion is becoming more and more serious,which makes travel time fluctuate greatly,especially in the morning and evening rush hours.Travelers hope to arrive at their destinations on time,so travel time becomes one of the most important factors to consider when they travel.Travel time reliability is a measure that describes punctuality and reflect the fluctuation of travel time.GPS data of taxis completely records all the information of vehicles during driving,it is of high accuracy and timeliness,and contains a large amount of data which can fully reflect the spatiotemporal characteristics of road network in a city.Combining weather data to quantitatively analyze spatiotemporal characteristics of road sections,a more accurate path travel time can be calculated,on the one hand,it can better help travelers in path planning,on the other hand,it also provides data support for urban road network construction and management.The main work and achievements of this article include:(1)Analyze GPS data of Chengdu taxis;rasterize Chengdu road network and combine it with Chengdu road network topology for map matching;Calculate travel time of each road section in morning and evening peaks and off-peaks,rainy days and non-rainy days respectively.(2)Travel time reliability is introduced to reflect probability,then it is used to establish the shortest travel time model considering reliability.On this basis,the rainfall factor and the buffer index variation ratio(BIVR)are used to reflect the impact of different rainfall intensity on travel time,and a path travel time estimation model with reliability considered under rain conditions is established.An ESLN distribution path travel time model based on time-varying characteristics is established to reflect path travel time at different time periods.According to the model,Dijkstra's algorithm is improved,and the shortest travel time path is calculated under the premise of ensuring reliability.(3)A dynamic path search model based on time-varying parameter matrix is proposed.Based on historical data,the travel time distribution fitting parameter matrix of each road segment in each time period is established.This search mode is important,it takes into account the impact of changes in the capacity of road segments during different times of the day on travel time,and improves the accuracy of path travel time when the road conditions change greatly.