SOME EVIDENCES OF CHAOTIC PHENOMENA IN SHORT-TERM TRAFFIC FLOW DYNAMICS: SURROGATE DATA APPROACH

Abstract

This paper employs wide-ranging indexes, including geometric plots and statistics, to examine whether chaotic phenomena exhibit in the short-term traffic flow dynamics. A field study is carried out using the one-minute flow time series data drawn from the United States 1-35 Freeway. The distinction of chaoticity and randomness is made between the original traffic data and their surrogates. We find that the geometric plots including iterated-function system clumpiness map, correlation function plot, and power spectrum have displayed apparent difference between the original and surrogate data and that the statistics including delay time, Hurst exponent, and relative complexity have also revealed noticeable discrepancy between them. These indexes have demonstrated strong evidences of chaotic, not random, phenomena in the nature of freeway one-minute traffic time series dynamics.