I'm trying to prevent vehicles from entering an intersection when its jammed up by using this setting (set to "NO") but it doesn't seem to help. has anyone else modeling congested networks experienced this?

Eric Royer
Caltrans

I've used this setting successfully before at an unsignalized T intersection. In my case, there was stop sign control on the minor leg (SB approach) and congestion westbound that caused queueing back through the intersection. I wanted to accurately model traffic entering mainline as observed in the field. I set the "Enter Blocked Intersection" field to 2 veh for both the SBL and SBR. I set the same field to 1 veh for WBT and No for the other 3 movements. This all worked--traffic from the minor leg was able to turn left and right onto the mainline despite the long WB queues on mainline.

I am having a similar problem to Eric. I tried the solution above, but the vehicles are still entering the intersection and blocking the side street vehicles from entering the corridor. Has anyone else experienced this situation and do you have any other ideas for addressing this situation?

yeah, I can't get them to stop entering the intersection.

I am also unable to prevent vehicles from entering the intersection. All of my "Enter Blocked Intersection" settings in the model are set to "No."

Although I have no solution, I think I may have isolated the problem.

I started a new model from scratch, rebuilding the model with problems. After each augmentation I made, I ran the simulation again (trying to find the exact point where my model had gone wrong). The traffic was consistently avoiding blocking the intersection. It was not until I added a bend in the downstream link that the queue started stretching into the intersection.

It appears that once a node is within 400' of the intersection, the traffic heading towards that node starts to ignore the "No" designation in the "Enter Blocked Intersection" attribute.

Please let me know if this is consistent with what you see.

Thanks,

Andy

yeah, mine has a closely spaced node downstream. Any thoughts on this John?

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I ended up submitting my model to Trafficware's online support. The response I received indicated that the numerous closely spaced driveways along the corridor were making it impossible for the model to run properly. The FHWA Traffic Analysis Tools Primer does acknowledge the limitations of the simulation software, but does not offer a solution.

I guess the solution is fewer driveways then. Is it possible to combine the traffic volumes at driveways if all you're reporting is LOS at the intersections?