  Universal characteristics of road networks and traffic patterns can help to
forecast and control traffic congestion. The antipersistence of traffic flow
time series has been found for many data sets, but its relevance for congestion
has been overseen. Based on empirical data from motorways in Germany, we study
how antipersistence of traffic flow time-series impacts the duration of traffic
congestion on a wide range of time scales. We find a large number of short
lasting traffic jams, which implies a large risk for rear-end collisions.
