Roundabout wizard Approach lane widths

[ralstogj]

Hi

I am trying to figure out the roundabout wizard and for the life of me can not get the entry and exit lane widths to match what I need.

Basically I just want the distance at the start of the approach to match what the width of my two road lanes which could be say the standard 4 and 3.75 or some different like 3.5m and 3.5m in a carpark.

But no matter what setting a use i never seem to be able to get the width at the start of the approach down to match these. Can some explain how the tool should be used to marry into lane widths of know width at the start of the leg?.

[lim.wendy · Accepted solution]

 Hi Justin,

The distance between two approach alignments used in roundabout is decided by four parameters, they are “Inner Offset”, “Width at departure”, “Width at approach”, “Central line width”. The relationship is show as formula below.

Distance = InnerOffset + WidthAtDeparture + CentralLineWidth + WidthAtApproach + InnerOffset. …”

For reference please see this link: http://docs.autodesk.com/CIV3D/2013/ENU/index.html?url=filesCTU/GUID-C4C1A0DA-F5DD-43D1-BF5B-B22EB7A...

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[ralstogj]

Thanks for the reply Wendy, I have managed to get there in the end for others here are some screen captures to show where the settings are. One thing you have to be aware of is a bit of a bug the centreline width is not ignored when unticked and you have to manualyl type in zero. Also each time you edit the roundabout the program automatically changes the centreline width back to the default so you have to type in zero again.