A lot of people were interested in comparing the US counties (see original post) to European metropolitan areas. I’ve graphed the results for four here. The method is unchanged, but the data source is different. Note that these cities are notably less gridded than the largest US cities.

Full-resolution version:

https://www.dropbox.com/s/6n54q5djse0dhqs/Road_Orientation_Europe.png

Data source: http://download.geofabrik.de/