Palmanova

Palmanova was built by the Venetians in 1593 and is called the star-shaped city. Palmanova is unique because its layout is geometrically perfect. It is surrounded by walls and moats that for about seven kilometers form this frame so harmonious. There are six roads converge toward the center and a hexagonal square. But did you also know that connecting streets to form hexagons instead of rectangles might lead to less traffic congestion. In a study, Luis Eduardo Olmos and José Daniel Muñoz at the National University of Colombia found that designing cities so only three streets meet at any given intersection – as they do when they form a honeycomb shape – could help get rid of traffic jams. The team ran a simple mathematical model allowing cars to drive diagonally in one direction, as might happen during rush hour when commuters all head home at once. For a square street network such as Manhattan, for example, the imaginary cars would run east and north to leave the city. With only a few cars, traffic flows smoothly, and when too many vehicles appear, traffic clogs. But in between those extremes, there's an extended intermediate state, where small traffic jams clog traffic in bursts across the network. When Olmos and Muñoz applied their model to honeycombed streets, however, they found something quite different. As the number of cars increased, the traffic transitioned suddenly, like water turning from liquid to solid: free-flowing traffic became a jam. With the addition of a few traffic lights to break up the flow, Olmos and Muñoz found that cars driving along honeycombed streets kept moving at densities that had already caused the rectangular network to clog up.

Dromos