As a clear signature of modern urban design concepts, urban street networksin dense populated zones are evolving nowadays towards grid-like layouts withrectangular shapes, and most studies on traffic flow assume street networks assquare lattices. However, ideas from forgotten design schools bring unexploredalternatives that might improve traffic flow in many circumstances. Inspired onan old and almost in oblivion urban plan, we report the behavior of theBiham-Middleton-Levine model (BML) \-- a paradigm for studying phasetransitions of traffic flow \-- on a hypothetical city with a perfect honeycombstreet network. In contrast with the original BML model on a square lattice,the same model on a honeycomb does not show any anisotropy or intermediatestates, but a single continuous phase transition between free and totallycongested flow, a transition that can be completely characterized by the toolsof classical percolation. Although the transition occurs at a lower densitythan for the conventional BML, simple modifications, like randomly stopping thecars with a very small probability or increasing the traffic light periods,drives the model to perform better on honeycomb lattices. As traffic lights anddisordered perturbations are inherent to real traffic, these results questionthe actual role of the square grid-like designs and suggests the honeycombs asan interesting alternative for urban planning in real cities.
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