Estimation of Expectation and Variance for a Section Travel Time based on Fragmentary Probe Trajectories

Abstract

This paper discusses how to estimate the expectations and the variances of section travel times with sample vehicle trajectories, such as probes. Since the individual travel time of a section may differ from each other, an advanced travel information service (ATIS) should provide not only the accurate expectations of travel times but also the accurate variances. The accuracy of that information depends on the number of available probe trajectories. However, especially in low penetration ratio of probes, it is difficult to expect sufficient samples which traverse the whole section. Therefore, we should consider utilizing fragmentary trajectories which traverse some part of the section. In this paper, we describe the methodology of travel time estimation with fragmentary probe trajectories. Then the accuracy of the estimation is validated with computational experiment by changing sample ratio and sampling strategies.