Mathematically Analyzing Traffic Flow
For years, engineers have debated over the superiority of various traffic flow models. Now the debate has finally been settled by researchers who made an intriguing discovery. That is, researchers from the Agency for Science, Technology, and Research (A*STAR) in Singapore found that two different models of traffic flow which have been previously been thought to be different, in fact have similar core mathematical structures.
Modeling Traffic
City architects, traffic engineers, and urban planners all rely significantly on traffic models to assist them in reducing heavy congestion in both rural and urban environments. Due to its asymmetrical properties, modeling traffic is considerably more difficult than modeling other natural systems. Symmetry in structure is often used to simplify models, therefore asymmetry results in an overwhelming number of model options. "It can be very difficult," admitted Bo Yang, a researcher from the A*STAR Institute of High Performance Computing , "to determine which is the most appropriate model for use in a particular traffic system."
The Models
The two most popular approaches to traffic modeling are the Two-phase traffic theory and the Three-phase traffic theory. Previously, these two theories were considered to be incompatible. Likewise, proponents of each of these models staunchly believed that their respective models were the best. The Three-phase traffic theory was developed around 2000 by Russian physics and vehicular traffic expert Boris Kerner. While the traditional Two-phase theory included the Free Flow and Congested Traffic phases, Kerner further distinguished the Congested Traffic phase into Synchronized Flow and Wide Moving Jam. Therefore, Kerner's three distinct phases are: Free Flow, Synchronized Flow, and Wide Moving Jam, symbolized F, S, and J.
Coming to Consensus
What Yang and his colleague Christopher Monterola discovered was that, mathematically, these two phases are intrinsically similar. That is, it is possible for a Three Phase Model to be estimated to a discretionary degree of accuracy by a specifically tuned Two Phase Model. "We believe that our study," said Yang, "has made one of the most crucial steps in resolving this long-standing controversy." Initial responses have been encouraging, though widespread acceptance will likely take time. Yang continued, "Our study reveals a universal mathematical structure that underlies all deterministic microscopic traffic models," adding, "this structure can be used to classify all such traffic models in the literature." This research enhances our understanding of universal driving behaviors, while also serving use in the development of dynamical algorithms for the new wave of autonomous vehicles. With fresh data and new research, it's time to hit the road.
Sources: Science Daily, The Agency for Science, Technology, and Research, Physical Review E, Physical Review Letters, Physics World Magazine, and the Transportation Research Record.
