On a multi-lane roadway in SimTraffic, is there a way to simulate no lane change forcing all vehicles to stay on their own lane within the link?

Hi Eric,

No, there is no direct way to do this at this time. If you have two lanes, they will choose the lane based on their lane change algorithms. About the only way I could think of doing this is to have two parallel links. But, than can be a bother to code.

Thanks,

John.

I've coded parallel links, but for a different reason - I had a 3 lane arterial become a 4-lane approach at an intersection, but it was the middle lane that split. so I split off the left lane, the next link I had the middle lane add a left turn lane, and then had it re-join the other lane before the signal.

Eric Royer
Caltrans

I can see how these work if it's a stop control or free flow condition. But my problem here is I have a two-lane freeway off-ramp merges onto a two-lane frontage road, and it becomes four lanes approach at the signalized intersection about 300 feet downstream. Lane change or cross over aren't allowed within the 300 feet between the off ramp and the signal. If I have two parallel legs in a signalized intersection, two protected phases are in conflict, it doesn't give me an acceptable result in Synchro analysis; and then in SimTraffic the turning movement yield to the through clogging up the network, even there is no conflict between the turning movements on one link and the through traffic on the other link.

The other thing I have tried is to merge the two links back onto one link before the intersection, and giving a four lane approach.
It does look better that way and giving me a more acceptable result in Synchro. But in SimTraffic, I just can't get rid of the lane change behavior within the short segment on the signal approach once the lanes free up for storage. I tried to change to mandatory distance, but seems like the free space lane change have a higher priority. Any thoughts?

Are there turning movements at the intersection downstream from where the ramp and frontage road merge? If you are only allowing volumes originating from the ramp to go thru and left, and the volumes on the frontage road to only go thru and right, then you might be able to clean up the simulation a little more by adjusting the origin-destination.

Under the Volume Setting window you should see a "Link OD Volumes" row with a button with each approach's direction on it. From there, you should be able to control which movement is feeding your downstream turning movements.

If the center two of your four lanes share a movement, you'd still have some weaving there.

I'm not sure if this will help, but thought I'd throw it out there.

Turning restriction are applied as Mark said, and the O-D has been modified to reflect that weave prohibition, too.
It is just the "random" lane change brother me the most.
I guess it just comes down to convince the reviewer/my boss, it's the software limitation on visualization.