Coherent moving states in highway traffic

• Published in: Nature (London) 1998-12, Vol.396 (6713), p.738-740
• Main Authors: Helbing, Dirk, Huberman, Bernardo A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Coherence; Density; Drivers; Exact sciences and technology; Ground, air and sea transportation, marine construction; Highways; Humanities and Social Sciences; letter; multidisciplinary; Physics; Road transportation and traffic; Roads & highways; Science; Science (multidisciplinary); Simulation; Traffic; Traffic accidents & safety; Traffic control; Traffic engineering; Traffic flow; Vehicles
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/25499

Advances in multiagent simulation techniques 1 , 2 , 3 have made possible the study of realistic highway traffic patterns and have allowed theories 3 , 4 , 5 , 6 based on driver behaviour to be tested. Such simulations display various empirical features of traffic flows 7 , and are used to design traffic controls that maximize the throughput of vehicles on busy highways. In addition to its intrinsic economic value 8 , vehicular traffic is of interest because it may be relevant to social phenomena in which diverse individuals compete with each other under certain constraints 9 , 10 . Here we report simulations of heterogeneous traffic which demonstrate that cooperative, coherent states can arise from competitive interactions between vehicles. As the density of vehicles increases, their interactions cause a transition into a highly correlated state in which all vehicles move with approximately the same speed, analogous to the motion of a solid block. This state is safer because it has a reduced lane-changing rate, and the traffic flow is high and stable. The coherent state disappears when the vehicle density exceeds a critical value. We observe the effect also in real Dutch traffic data.