[talk-au] traffic lights on dual carriageway intersections
alex at softgrow.com
Sat Nov 3 10:55:22 GMT 2012
On 3/11/2012 5:33 PM, John Henderson wrote:
>> I checked some intersections in Melbourne’s CBD, and the method I saw
>> that I liked and thought the best was where there were 4 lights at
>> the intersection, but they were not placed on the intersecting modes,
>> but one node back “upstream” on each way. I think this is good
>> because no matter which way you go through the intersection, you only
>> pass one set of lights (rather than 2 if they were placed on the
>> actual intersecting nodes).
I read it and liked it but then poked around near me but found that
traffic signals where a divided road meets and undivided road, the
undivided road gets a count of two. You could put the undivided (two
ray) road traffic signals in the centre of the intersection but that
starts to look pretty strange.
Which then leads us to possible accusations of mapping for the "routing
renderer". Strictly speaking the traffic lights are things on poles
placed on traffic islands as well as overhead gantries. Should we be
tagging the physical object, ie. the signal rather than its effect which
is most pronounced at the stop-line?
Another thought would be to tag the stopline with a direction tag to
hint the renderer that a vehicle would stop here moving in a particular
direction..starts to get complicated. What about wig-wags outside
fire-stations or supplementary traffic signals applied to a level
crossing. Starts to get tricky..
Still worth thinking about...
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