Telegraph Article - Is this the end of the road for traffic lights?

[agentsteel53]

They're all over, but not overused (well, maybe a little), and effective.

okay, I'll bite.  what's the purpose of that one?  traffic coming out of that parking lot to the northeast can make a U-turn? 

[Scott5114]

I believe to meet the definition of a "roundabout" (as opposed to a "traffic circle") there's not supposed to be pedestrians on the central island at any time, so the crosswalks would be on the approaching roads, not the circulating road.

[roadfro]

They're all over, but not overused (well, maybe a little), and effective.

okay, I'll bite.  what's the purpose of that one?  traffic coming out of that parking lot to the northeast can make a U-turn?

That's what I thought as well...looks to be a trip over the river about half a mile to the next roundabout to head back eastward. There's two parking lots that have U-turns served by that roundabout. Assuming the road designers were trying to save mature trees in the median, the roundabout makes sense (although the ability to make eastbound U-turns does not...it could have simply been designed as a channelized U-turn).

[doorknob60]

They're all over, but not overused (well, maybe a little), and effective.

okay, I'll bite.  what's the purpose of that one?  traffic coming out of that parking lot to the northeast can make a U-turn?

That's what I thought as well...looks to be a trip over the river about half a mile to the next roundabout to head back eastward. There's two parking lots that have U-turns served by that roundabout. Assuming the road designers were trying to save mature trees in the median, the roundabout makes sense (although the ability to make eastbound U-turns does not...it could have simply been designed as a channelized U-turn).

Yeah, that's what it's for. A lot of people use the parking lots at Farewell Bend Park, so it's certainly useful to have, but it still seems odd. And there's no reason it needs to be a full circle either (it serves no purpose for eastbound travelers). Also, maybe they use it to slow people down. The speed limit is 25 the entire stretch from Century Dr. to 3rd St., but people often go 30-35 or more, and I've seen up to 45 down the hill and across the bridge (though that's pretty sketchy)

[1995hoo]

We have a seemingly useless roundabout nearby as well–see link: http://goo.gl/maps/XMDov –and I have no idea why it was put there unless they plan to extend Dudley Drive further across towards Silverbrook Road. They can't extend Laurel Crest Drive because of the houses already located there. The roundabout went in a few years ago when the golf course was being constructed on land that used to be part of the Lorton Reformatory complex (a prison that belonged to the District of Columbia). I might have thought it could be useful for U-turns except the two schools located nearby seem to serve that purpose well enough.

[kphoger]

Yeah, I assume it's like this Kansas example (triangle variant):  development is/was expected to create a third leg.