Hi there,

I am working on a simple network and all traffic seems to be using only one lane out of 2 lanes.

I'm sure there is a mistake in the parameters I have set for Lane Settings.

Please help.

Many thanks in advance.

Kashyap Shukla
Mott MacDonald

Roundabout_-_lane_settings.pdf (207 KB, 40 downloads)

the roundabout model in simtraffic is really hard to get to work "the way you want it too". They have a long way to go on this if you ask me, and it should be a BIG part of any new version of the software, hopefully.
I'd check your number of circulating lanes, and your number of exit lanes. I'm not sure what other things you can adjust to make this work - I'm not sure what guidance trafficware has out there to help on this matter.

Eric
Caltrans

MottsUser,

You need to create upstream nodes with widening median widths, and also change the number of exiting lanes for each approach. Click on the roundabout, and then click on the "stop" tab on the top. Then, change the exiting lanes appropriately.

The upstream nodes/median widths are sometimes necessary for Synchro to allow for the correct lane usage.

See attachement...

roundabout_example2.pdf (15 KB, 50 downloads)

The circle (both inner and outer) size, entry median width, offset and angle all play as factor in determining the roundabout lane use. I don't know how are they related and interpreted in Synchro to get the lane use works, but it's some time a trail and error setup to move around the link or other input factors to get the lane use works.

I recently did a project with a three lane roundabout which Trafficware says it's okay to simulate. (I was just looking for a graphic animation on operation, rather than the result.) But after I moved around the approach legs to better represent the field layout, everything get messed up and just couldn't code it as it should be in term of lane usage. I just gave it up at last. Totally agree with Eric from Caltrans, Trafficware should really look into this matter for future upgrade.