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I may be being a bit of a pedant but do you mean roundabout? Traffic circles and roundabouts are different. A traffic circle, in the modern sense, does not have

I may be being a bit of a pedant but do you mean roundabout? Traffic circles and roundabouts are different. A traffic circle, in the modern sense, does not have much horizontal deflection on the entering legs. The diameter is also smaller and there is not a truck apron. A roundabout on the other hand has some form of horizontal deflection and a truck apron. Often times a traffic circle can be installed by placing a round bit of curbing in the center of an existing intersection. These are great in low volume low speed applications such as neighborhoods. Traffic circles have a much lower capacity than a roundabout due to the low travel speeds. Again, sorry for being a pedant but I am a traffic engineer and the distinction between these two traffic control devices matters. Here is a link to roundabout specific information from the Federal Highways Administration https://safety.fhwa.dot.gov/intersection/innovative/roundabouts/ https://safety.fhwa.dot.gov/intersection/innovative/roundabo...

bluntfang 7y ago
>the distinction between these two traffic control devices matters To reflect your pedantic efforts: does it matter in _this_ discussion? Colloquially they are the same thing when not having a technical discussion.
souprock 7y ago
Traffic circles and roundabouts don't exist. Those things are all called rotaries. The tiny ones are inherently defective, especially for large vehicles. The larger rotaries can be nice, especially when installed above a freeway that intersects with low-volume roads, but they are too costly unless the land is very cheap. A decent use of a rotary is in Massachusetts where Drum Hill Road and Old Westford Road meet US 4 (North Road) right over top of Interstate 3. It's a 6-way intersection, with the elevated rotary helping to deal with the high speed of Interstate 3. The intersection used to be even nicer, free of traffic lights and with a smooth elliptical shape, prior to Interstate 3 being widened.
- selimthegrim 7y ago
  Surely you mean US 3 and MA 4
- takk309 7y ago
  A rotary has higher speeds and entering traffic gets the right-of-way. They are very different from a roundabout.
bonestamp2 7y ago
You are correct, it is technically a roundabout. $1.3 million for a single lane roundabout with a raised median. Does that cost sound reasonable?
- takk309 7y ago
  It really depends on the agency building the roundabout and the property values at the intersection. For example a rural intersect near me just got a single lane roundabout and it cost $3.2 million. The agency building it prefer a lot of concrete over asphalt. Other states can build them for less if they use asphalt.

bluntfang 7y ago

>the distinction between these two traffic control devices matters To reflect your pedantic efforts: does it matter in _this_ discussion? Colloquially they are the same thing when not having a technical discussion.

souprock 7y ago

Traffic circles and roundabouts don't exist. Those things are all called rotaries. The tiny ones are inherently defective, especially for large vehicles. The larger rotaries can be nice, especially when installed above a freeway that intersects with low-volume roads, but they are too costly unless the land is very cheap. A decent use of a rotary is in Massachusetts where Drum Hill Road and Old Westford Road meet US 4 (North Road) right over top of Interstate 3. It's a 6-way intersection, with the elevated rotary helping to deal with the high speed of Interstate 3. The intersection used to be even nicer, free of traffic lights and with a smooth elliptical shape, prior to Interstate 3 being widened.

selimthegrim 7y ago
Surely you mean US 3 and MA 4
takk309 7y ago
A rotary has higher speeds and entering traffic gets the right-of-way. They are very different from a roundabout.

bonestamp2 7y ago

You are correct, it is technically a roundabout. $1.3 million for a single lane roundabout with a raised median. Does that cost sound reasonable?

takk309 7y ago
It really depends on the agency building the roundabout and the property values at the intersection. For example a rural intersect near me just got a single lane roundabout and it cost $3.2 million. The agency building it prefer a lot of concrete over asphalt. Other states can build them for less if they use asphalt.