Identification of country specific characteristics of oscillating congested traffic

This thesis aims at a country specific analysis of freeway traffic oscillations. Toward this end, loop detector data from sites in the USA, Germany and the United Kingdom (UK) was analyzed. By using a method applied in previous work, traffic oscillations were identified in all three countries. Calculation of the cross–correlation coefficient reveals that they travel upstream at speeds of about 19–20 km/h at the site in the USA, 16 km/h at the German site and 14 km/h on the UK freeway. Similar magnitudes were found in the literature verifying the hypothesis that they propagate faster in the USA than in Germany. Furthermore, an oscillation frequency was identified by calculation of the data’s autocorrelation. For the sites analyzed, it was found that oscillations appear every 8 – 12 min in the UK, 10 – 30 minutes in Germany and every 3 – 6 minutes in the USA. The magnitudes for the latter two countries are supported by the literature; therefore this indicates that a general difference in the oscillation frequency exists. However, further research on different sites is needed to verify this statement. Since a relation between the frequency and amplitude of traffic oscillations is believed to exist, this would also indicate that the amplitude is usually lower in the USA than in Germany.