Once Google Maps reached sufficiently high-resolution satellite images to actually see all of the gravel roads, I was actually a bit awestruck. The majority of the state of Iowa looks like a sheet of graph paper.<p>I grew up a in the region and spent plenty of time driving around endless country roads. It's just so weird to see it from above, all at once. Makes one appreciate the skill of surveying without the modern aid of gps.
In Australia, we have a 146 km straight stretch of road[1]. That's part of 1000 km+ of pretty-much-straight road[2][3]. It's difficult to express how isolated that area is.<p>[1] <a href="http://www.abc.net.au/news/2009-10-13/sign-at-the-start-of-90-mile-straight-australias/1102102" rel="nofollow">http://www.abc.net.au/news/2009-10-13/sign-at-the-start-of-9...</a><p>[2] <a href="http://www.amusingplanet.com/2014/11/the-long-and-lonely-eyre-highway-worlds.html" rel="nofollow">http://www.amusingplanet.com/2014/11/the-long-and-lonely-eyr...</a><p>[3] <a href="https://www.google.com.au/maps/@-32.5176141,126.9613846,7z" rel="nofollow">https://www.google.com.au/maps/@-32.5176141,126.9613846,7z</a>
Very well presented and interesting analysis.<p>Primary compliments I also have in particular for the author is inclusion of a link to source code and the concise but complete and informative "tools used section" describing the process. I wish more analysis (particularly those presented on more reputable news outlets) was presented with a similar section for reproducibility and exposure to analysis techniques.
The site's not loading for me (swamped?) so this is based just on what I can infer, but the thing that popped into my mind was the U.S. Midwest. As an avid motorcyclist, I am always seeking out curvy roads. I just got back from a three week vacation in Italy where there was rarely a straight road to be found (in the Chianti area, the GPS would be set for fastest route, the destination would be 60 kilometers away, and the GPS would estimate 2 hours to arrive.). But there are areas in Kansas where, if the earth were flat, you could see someone 30 miles ahead of you .
I'd be interested in calculating just a subset of roads and comparing to the overall average. Dual carriageways are the most likely to adapt the terrain to the road rather than building the road to the terrain. If I recall correctly, Germany has the strictest requirements for the straightness, and the States has a rule that every X miles must have a section that can be converted to an impromptu landing strip. The website is completely crushed right now, but once it's back I may play with the data.
Netherland has a lot of polders, which are very flat, and particularly the largest polders (Flevoland, Wieringermeer, Haarlemmermeer) are very recent (last 200 years) and have a lot of perfectly straight roads. It's a shame the Afsluitdijk got divided between 4 pixels instead of getting its own pixel, or you might have had one pixel of 100% there.<p>Also, we're pretty boring and organized people. You should see how perfectly the trees in our "forests" are lined up. Also straight.