I’m sure you’ll forgive me a brief digression into road geekery. In yesterday’s New York Times, there was an article about how MapQuest et al. fail to display regionally unique intersection geometries, such as frontage roads, jughandles (at right), and Michigan lefts. Which is as good an excuse as any for the article to describe them, because they’re really neat, and to link to the Unconventional Arterial Intersection Design page, which showcases some examples of unorthodox intersections that might be unfathomable to out-of-towners. Via Gadling.
I remember the confusion in Winnipeg when a centre left-turn lane, common elsewhere but new to my city, was installed on St. James Street as part of lane control; some interchanges along Deerfoot Trail in Calgary are also a bit atypical; and those familiar with European right-of-way rules might find North American roundabouts, where the car at right does not necessarily have the right of way, counterintuitive. The question is, how do you map such differences? You probably can’t.