Dynamic Traffic Flow–Dispersion Model Based on TTI of Floating Cars

Abstract

This paper presents a probability distribution model of vehicles’ travel time index (TTI) in urban road segments that depicts traffic flow dispersion. Compared with traditional models, it can depict traffic flow dispersion with a uniform model under conditions of different road speeds or road lengths. Based on it, a dynamic model that depicts how the TTI distribution parameters vary with speed of road segment is proposed. Furthermore, parameters of the dynamic model are used to construct a characteristic vector to reveal a new inherent feature of road segments. The tests of goodness of fit for the two proposed models were carried out with data collected from 66,000 floating cars. The test area covered 40,400 urban road segments in the urban area of Beijing. Test results showed that more than 98% of the tested bins accepted the proposed TTI probability distribution model, and more than 90% of the tested road segments accepted the proposed dynamic model. The proposed models would be applied in traffic simulation, congestion forecast, signal control, and other relevant fields in the future.