On Thu, Jun 23, 2011 at 10:26 AM, Pieren <pier...@gmail.com> wrote: > On Thu, Jun 23, 2011 at 1:49 PM, John F. Eldredge <j...@jfeldredge.com>wrote: > >> often with a graveled shoulder extending a little further. This >> situation would logically be mapped as kerb=no. I have seen flush curbs as >> well, presumably where a road has been repaved multiple times without >> milling away the old pavement. From a purely functional view, this is the >> same thing as having no curb, and is likely to be paved over the next time >> the road is resurfaced. >> >> > hmmm, very confusing. Finally, what is the difference between flush kerbs > and shoulders ? >
A shoulder is the area next to the outer travel lanes. This can be paved or unpaved. On rural roads in the US the shoulder typically consists of gravel and it's unlikely there are any curbs. On other roads it is typically paved, and can be anywhere from a few inches to the width of a travel lane, such that emergency vehicles can it as a travel lane. If a kerb is present, the shoulder terminates at the kerb. http://en.wikipedia.org/wiki/Shoulder_%28road%29 Kerbs are the raised edges of the roadway meant to channel stormwater, among other purposes. In this sense it is a bit incorrect to say the kerb is flush, but rather saying kerb=flush indicates that at the location where a kerb is normally present (implying a change in height), instead there is no change. This can either be accomplished by raising the crossing to the level of the sidewalk as depicted here: http://www.fhwa.dot.gov/environment/sidewalk2/figure812.jpg Or by "cutting" through a kerb so no change in height is experienced at all (often at medians/islands): http://www.fhwa.dot.gov/environment/sidewalk2/figure084.jpg http://streetswiki.wikispaces.com/file/view/ped-refuge-island-santacruz-burden.jpg/129479409/ped-refuge-island-santacruz-burden.jpg Interestingly I came across the "Kassel kerb", which guides the tires of stopping buses for an almost level entry (low floor buses): http://en.wikipedia.org/wiki/Kassel_kerb By the way, if you want to know more about sidewalks, curbs, crossings, etc, the US Federal Highway Administration has a comprehensive document. It would be interesting to know if transportation agencies from other countries have this kind of document: http://www.fhwa.dot.gov/environment/sidewalk2/ -Josh
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