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http://dx.doi.org/10.12815/kits.2018.17.1.79

Exploring Smoothing Techniques for Reliable Travel-Time Information in Probe-Based Systems  

Jang, Jinhwan (Dept. of Highway Res., Korea Inst. of Civil Eng. and Building Tech.)
Publication Information
The Journal of The Korea Institute of Intelligent Transport Systems / v.17, no.1, 2018 , pp. 79-88 More about this Journal
Abstract
With the increasing popularity of electronic toll collection system using 5.8 GHz dedicated short-range communications (DSRC) technology, DSRC-based travel-time collection systems have been deployed on major urban and rural arterial routes in Korea. However, since probe sample sizes are frequently insufficient in probe-based systems, the gathered travel times from probe vehicles fluctuate significantly compared to those of the population; as a result, the accuracy of the collected travel times could decrease. To mitigate the fluctuations (also known as biases), smoothing techniques need to be applied. In this study, some smoothing techniques-moving average, the Loess, and Savitzky-Golay filtering-were applied to probe travel times. Resultantly, the error in the smoothed travel times at the lowest sampling plan (5%) decreased as much as 45% compared to those in non-smoothed travel times. The results of this study can be practically applied to probe-based travel-time estimation systems for providing reliable travel times along the travel corridor.
Keywords
Travel time; Smoothing; Moving average; Loess; Savizky-Golay filterin;
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