Saturday, May 28, 2011

On Hexagons

Shoot. Without even thinking, I checked my email again. So you get another post.

This past Tuesday, during History of London lecture, I could barely focus on what Geoffrey Tyack was saying. His classes are usually really interesting, but this time he just wasn't doing it for me. The whole lecture focused a lot on urban planning ideas for nineteenth- century London. Woo-hoo. It reminded me about the time I almost took Intro to Urban Studies but dropped it after two lectures.

What I started thinking about instead of listening to lecture were hexagons. I think they would make for a very interesting shape for urban planning. They are one of the three regular polygons you can tessellate (the others are equilateral triangles and squares). Cities tend to be laid out in rectangular grids. This may be the most logical layout in some respects, but it is very inefficient and ugly in others. The hexagon, on the other hand, is closer to a circle, which is sort of a more attractive shape than a square, and offers some practical advantages as well.

The main cool thing about a hexagonal grid is that every hexagon, or plot of land in the case of urban planning, shares a whole side with its neighbors. In a rectangular grid, every rectangle has four adjacent neighbors connected only by corners. Another four are connected by sides. Hexagons have only six neighbors, all connected along sides. For this reason, there are my strategy games built using hexagonal tiling. This is also sort of why it's a shape that occurs in nature fairly often. Think about honeycombs, graphene molecules, and all sorts of molecular rings.

Another cool thing about hexagonal urban planning is that intersections would all be three-way intersections. At first, the thought of a 3-way, 120-degree, triangular intersection may be strange. It has, however, some key advantages. First, it's easier to see people coming at 120 degree angles than at right angles. Second, there are only three places for cars to crash. Only two turns are possible - a slight right or slight left. The slight right is totally safe. If you make a slight left, you may hit someone else making a slight left from a different direction. If there are three intersecting streets, A, B, and C, you can have A-B left turn crashes, A-C left turn crashes, and B-C left turn crashes. Compare this to your common 4-way intersection, where there are 10 places for cars to crash. I won't get into analyzing that, but it's simply a more dangerous intersection.

With 120-degree turns, trips that go on diagonals will, I think, be shorter than traveling on a rectangular grid. People may get carsick more often, though, because paths would usually be zig-zags. There are good ways to avoid this, however, where main thoroughfares could crisscross neighborhoods at 120-degree angles. This would keep the advantage of making trips that weren't straight north or south shorter while maintaining the main features of a hexagonal grid.

I could keep going on about the advantages of the hexagonal grid. There are a lot of aesthetic ones. Of course, there are also distinct disadvantages to hexagonal grids, like how it would be really hard to name streets. It would be easier to recognize rows of land plots than streets. I got a lot more ideas about hexagons after class, when I read this paper ( It detailed the interest in hexagonal urban planning around 1920 and 1930, and gave historical reasons why the plans were never really implemented. It's not purely that it's such a bad idea, just that it never caught on the way the gridiron and the neighborhood unit of cul-de-sacs and loops did. For the cities, the gridiron was more logical, and in suburbs, the garden-city ideal was better fitted with cul-de-sacs and loops.

Anyway, I don't think the hexagon ever got it's fair share of attention. I think, if I am ever to do any sort of urban planning, I may give hexagonal planning the shot it never got.

1 comment:

  1. I entirely agree. I have been searching tirelessly for someone else who supports the idea of hexagonal grid cities.