  Traffic systems can operate in different modes. In a previous work, we
identified these modes as different quasi-stationary states in the correlation
structure. Here, we analyze the transitions between such quasi-stationary
states, i.e., how the system changes its operational mode. In the longer run
this might be helpful to forecast the time evolution of correlation patterns in
traffic. We take Cologne orbital motorways as an example, we construct a state
transition network for each quarter of 2015 and find a seasonal dependence for
those quasi-stationary states in the traffic system. Using the PageRank
algorithm, we identify and explore the dominant states which occur frequently
within a moving time window of 60 days in 2015. To the best of our knowledge,
this is the first study of this type for traffic systems.
