Network Spacing & Queueing TE's

I'm trying to see if there is an elegant/simple solution to a problem we have encountered with TE's on a network. The spacing values are set and each TE has a different speed on the network. When TE's queue behind the slowest they all move together, when the slow TE crosses a NN to a new section the spacing rule stops being in effect (as it is defined for the path not the whole network?) and the TE's behind accelerate into the space then stop at the NN till the gap comes back. Overall it's more of a visual issue than a results one but has anyone come across this and solved it?

Hi,

to build what you are looking for I nomaly only create another NN in front of the NN where your slowest TE stops and use Traffic Control. This works very fine if you only have 2 TE in line. It also could be a solution for 3 TE. But if you want more, effort will rise and you will have to find another solution.

Thanks for that, it would be a good solution for a smaller number of TE's but just get too much for some of the numbers involved.

How many TE´s are involved in your model?

Originally Posted by Sebastian Hemmann

How many TE´s are involved in your model?

Hi Sebastian,

Mike is trying to help me with this issue.

It's around 20 TE's (which are trucks in a open pit mine). The problem becomes very noticeable when there is a Grader travelling at 5km/h and all trucks around it at 50km/h on non-passing road segments.

Any help would be appreciated.

Hi,

can you share a small example model please. I think the answer would be to adjust the Network.
My first solution would be to find out where TE´s are allowed to pass the slower truck. And with this information I would build a Network that only at this points got Networknodes.
Now you only Need a logic for priority in traffic.

greetings

Hi Sebastian,

Actually, TE's would never be allowed to overtake other TE's. If there is a slower TE at the beginning of the line, all TE's behind it would have to stay there and follow the slower TE at its speed.

Attached is a simple model demonstrating the problem. Notice that after the slow operator has passed through the first node, the operators behind it, that are faster, speed up, and stop at the node waiting for the space between them to be the segment spacing.

I just wanted the fast operators to follow the slow one, at a constant slow speed.

Thanks for your help.

Andre.

Ok, thanks for the model. So my idea was to proof if your realy Need NN2 - NN5. In the models I´ve build I only needed NN´s for using their Triggers to start any logic.
So i would try to reduce number of used NN´s to the Points, where TE really has to stop an build there the solution with Traffic control.

So as you can see TE´s stop in line.
Now it Looks as if you also have to build some own Tasksequences to make all TE´s unload their items.

Hello Andre,

I have made an example for you how to change the speed limit of an edge on arrival of a traveler. (at NN2).

This will change the speed permanently though and only for one node.

You would have to set the speed limit back to a default value OnReset and maybe during the model run, but I hope this helps you in the right direction.

Esther

I like Esther's concept. If you only care about the travelers respecting each other's max speed and not assigning speed limits to individual paths then the following can work decently well, but you will need more frequent nodes on the network. Still not a perfect fix.

OnArrival of all NNs:

//if there are no active travelers on my toedge, set its speed limit to my max speed
treenode portnode = rank(connectionsout(current),toedge);
if(content(rank(portnode,PORT_ACTIVE)) == 0)	//no travelers ahead of me to govern my speed
	set(rank(portnode,PORT_SPEED),getvarnum(traveler,"maxspeed"));

Pretty sure you don't have to optimizenetwork() since the navigator's distance table does not involve speeds.

Thanks a lot, guys.

Sebastian,
I do need all the network nodes. There are other things happening in the model that prevent me from deleting the extra nodes.

Esther and Kris,
Yeah, I think that's the way to go, changing the speed limit of the segments as the trucks pass through nodes.

Thanks again,
Andre.