Travel time reliability using the Hasofer-Lind-Rackwitz-Fiessler algorithm and kernel density estimation

Shu Yang, Arif Malik, Yao Jan Wu

Research output: Chapter in Book/Report/Conference proceedingChapter

28 Scopus citations


Travel time reliability has emerged as an indicator of roadway performance. Estimation of travel time distribution Ls an important starting input for measuring travel time reliability. This study used kernel density estimation to estimate travel time distribution. The Hasofer- Lind-Rackwitz-Fiessler algorithm, widely used in the field of reliability engineering, w as used in this work to compute the reliability index of a system based on its previous performance. The computing procedure for travel time reliability of corridors on a freeway was introduced, then network travel time reliability was developed. Given probability distributions estimated by the kernel density estimation technique and an anticipated travel time from travelers, the two equations of corridor and network travel time reliability can he used to address the question, "How reliable is my perceived travel time?" The definition of travel time reliability was in the sense of on-time performance, and this study was conducted from the perspective of travelers. The major advantages of the proposed method are as follows: (a) it demonstrates an alternative way to estimate travel time distributions when the choice of probability distribution family is still uncertain and (h) it shows its flexibility for application to levels of roadways (e.g., individual roadway segment or network). A user-defined anticipated travel time can be input, and travelers can use the computed travel time reliability information to plan their trips so that they can better manage trip time, reduce costs, and avoid frustration.

Original languageEnglish (US)
Title of host publicationTransportation Research Record
PublisherNational Research Council
Number of pages11
ISBN (Electronic)9780309295321
StatePublished - 2014
Externally publishedYes

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Mechanical Engineering


Dive into the research topics of 'Travel time reliability using the Hasofer-Lind-Rackwitz-Fiessler algorithm and kernel density estimation'. Together they form a unique fingerprint.

Cite this