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Will jams get worse when slow cars move over?

B. Schmittmann·J. Krometis·R. K. P. Zia
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Abstract

Motivated by an analogy with traffic, we simulate two species of particles (`vehicles'), moving stochastically in opposite directions on a two-lane ring road. Each species prefers one lane over the other, controlled by a parameter $0 \leq b \leq 1$ such that $b=0$ corresponds to random lane choice and $b=1$ to perfect `laning'. We find that the system displays one large cluster (`jam') whose size increases with $b$, contrary to intuition. Even more remarkably, the lane `charge' (a measure for the number of particles in their preferred lane) exhibits a region of negative response: even though vehicles experience a stronger preference for the `right' lane, more of them find themselves in the `wrong' one! For $b$ very close to 1, a sharp transition restores a homogeneous state. Various characteristics of the system are computed analytically, in good agreement with simulation data.

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B. Schmittmann, J. Krometis, R. K. P. Zia. 2005-03-17. Will jams get worse when slow cars move over?. https://doi.org/10.1209/epl%2Fi2005-10006-6

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