Practical approach for travel time estimation from point traffic detector data

Accurate estimation of travel time is critical to the success of advanced traffic management systems and advanced traveler information systems. Travel time estimation also provides basic data support for travel time reliability research, which is being recognized as an important performance measure of the transportation system. This paper investigates a number of methods to address the three major issues associated with travel time estimation from point traffic detector data: data filling for missing or error data, speed transformation from time-mean speed to space-mean speed, and travel time estimation that converts the speeds recorded at detector locations to travel time along the highway segment. The case study results show that the spatial and temporal interpolation of missing data and the transformation to space-mean speed improve the accuracy of the estimates of travel time. The results also indicate that the piecewise constant-acceleration-based method developed in this study and the average speed method produce better results than the other three methods proposed in previous studies. Copyright (c) 2011 John Wiley & Sons, Ltd.