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Old 11-27-2018, 02:56 PM   #85
sjfan
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Quote:
Originally Posted by HarryT View Post
There does seem little benefit to roundabouts in that sort of area, I agree. Their benefit is in maintaining smooth traffic flow on busy roads. They're pointless on quiet roads.
Most studies show the opposite; roundabouts are especially good relative to signals on low- and medium- traffic roads and those with tons of left turns. They tend to have lower traffic flow than signaled intersections on high-traffic roads.

And because they are flow-controlled by a yield-on-entry approach, they are especially poor on interchanges where there are unbalanced entries (e.g. smaller arterial roads crossing high-flow roads).

See https://academics.utep.edu/Portals/1..._Rab_ver7a.pdf

Also https://www.acsengineers.com.au/2016...raffic-lights/

It's led to the curious situation where the US is adding tons of roundabouts (in smaller cities and towns, and less busy parts of big cities) while the UK is seeing a boom in new signalled intersections (at busy intersections).

https://www.theguardian.com/cities/2...abouts-way-out
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