Level of Service Estimation based on Low-frequency Floating Car Data

Abstract

Systematic and network-wide estimation of traffic quality is an essential requirement for a traffic management. Collecting traffic information based on conventional sensor techniques becomes an economical challenge when road authorities are faced with wide-area road networks. With respect to nowadays strictly limited resources, the cost-efficient analysis of historical driving speeds based on mass floating car data (FCD) is getting more and more important in modern traffic management. The representative calculation of typical driving speed for identical weekdays over a certain period allows the ex post identification of periodic bottlenecks and could be also used to evaluate the effects of management strategies. Therefore, the objective of this paper is to present a four stage semi-automatic method for a network-wide level of service estimation based on processing historical FCD. During the first and the second chapter the paper gives a summary over related work in this research field and introduces the used floating car data source as well as the applied digital roadmap based on OpenStreetMap. During the first stage, the developed method establishes an easy to use referencing process between the digital road network and the traffic message channel system (TMC). Based on the road network separation with respect to the TMC-system, the second stage employs a FCD matching algorithm, which allows the detection of driving direction especially for low-frequency floating car data and small TMC-segments. The third stage of the method deals with the systematic and statistical analysis of historical driving speeds. Therefore, the paper analyzes the statistical significance level of derived average driving speeds over two hour time intervals for typical weekdays. The fourth stage of the method describes a self-calibrating level of service calculation process which uses speed indices. Finally, the paper exemplifies results of the developed method for the road network of Hanover (Germany).