Figure 2

Demonstration of a typical strong link. During the dates 26–30 Oct. 2015 in RH1. The two road sections (nodes) are \(i=821\), \(j=964\) (See (a)), with \(W^{\mathrm{pos}}_{i,j}=4.47\). (a) The location of the two nodes on the map. The red and the magenta lines indicate the two road sections i and j. (b) Cross-correlation \(X_{i,j}(\tau )\) VS τ. The maximum correlation is 0.4102, at time lag \(\tau =2\) (minutes). (c) Shifted time series for the example in (a, b). For this link, the peak of the cross-correlation function at \(\tau =2\) (minutes) suggests an influence with a clear direction from i to j