Routing errors : Help needed

[Venktesh Pandey]

Hi all,

While running router in TRANSIMS I found that majority of my trips didn't get routed because of Path building and Access Restriction errors.

Delving in 'Problems' file written by router, I found that majority of the problems were for leg 0 of trips made by mode-2.

A small sample from my problem file is as under -

HHOLD	PERSON	TRIP	LEG	MODE	PROBLEM	START	ORIGIN	ARRIVE	DESTINATION
155	1	1	0	2	1	12:39:21	63	12:41:53	355
156	1	1	0	2	1	7:36:02	34	7:38:40	356
157	1	1	0	2	1	16:52:02	41	16:54:52	355

3096	1	1	0	2	25	11:38:48	355	11:41:37	39
3097	1	1	0	2	25	15:34:16	355	15:37:18	261

I referred documentation for details on this, and what keeps me puzzled is that

a) Leg values for all non-routed trips is zero ( Leg values as per documentation start from 1 ).

b) Majority(90%) of the non-routed trips either originate or terminate at activity locations in external zone

I clearly checked with my network, the links in my external zone were all accessible and shouldn't pose a path build problem.

I reviewed several of previous group posts on this topic, but none to my help.

Can anyone help me out what would possibly be wrong. Or is it related with walking mode(mode-2) for all trips? Also what 'leg value 0' means?

Thanks in advance.

Venktesh Pandey

Final year undergratuate

Civil Engg.

IIT  Bombay

[Asadur Rahman]

Based on my understanding

a) The trip could not start, so there is no leg. And as there is no leg, the value is zero. According to Leg Definition: "A leg describes a traveler’s movement through the network. A leg must start and end 

at an activity location, parking location, or transit stop."

According to Version 4, Mode 2 means walk at the output from Router. 

b) I think you already check the following reasons of path building problem, still

 1) lane connectivity or 

 2) one-way street conditions or 

 3) a network coding error

Some of observations

1) Sometimes, the ANODE and BNODE issue of individual link makes problem. You need to make sure the traffic flow is channelized. 

2) I am wondering what you have assigned at "FIRST_EXTERNAL_ZONE_NUMBER" in the TransimsNet control file

3) If you manually edit your network (specially TAZ for activity locations), you need to be consistent with "Process Link". 

4) You may also check the "Lane Connectivity" file by making maps, if it really make sense. 

Hope it provides some idea.

Asad.

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[Roden, David]

Assuming mode=2 is a walk trip, all links from the origin to the destination need to permit walking (link use code).  It would be unusual for external stations/zones to include have walk trips.

 

David B. Roden, P.E.

Senior Consulting Manager

AECOM

2101 Wilson Boulevard

Suite 800

Arlington, VA  22201

david...@aecom.com

703-340-3069

[Venktesh Pandey]

Hi,

Thanks for those ideas.

I think I still need to scan the network precisely for those path building errors.

Btw I kept all links bidirectional by defining a lane in opposite direction too (Lanes_AB and Lanes_BA both have non-zero values). So that shouldn't be a trouble for channelization of traffic.

My network has 2 external zones and I kept value of 'FIRST_EXTERNAL_ZONE_NUMBER' as start of my external zones mentioned at bottom in zone file. Also included these as nodes at top of node file. Named all links attached to external zone as 'EXTERNAL'
I also tried with zero as value for MAX_CIRCUITY_RATIO.

Though my links have different setback distances (like some have 0 for both direction, other 7.5 for both, or mixed). Should that cause problem with lane connectivity?

I also think Mode=2 in trip file generated by convertTrips (also carried in problem file), might not mean walking mode. Because for Alexandria case(Track-1 implementatn in Version-4) even I found that all trips in Trips file either had Mode=2 or Mode=11, and according to Route planner documentation as attached, mode value shouldn't be more than 4.

Also it doesn't make sense with putting a precise Mode value, given that a trip can have several legs with different modes each.

It should mean something different(which I'm not able to locate)!!

Venktesh Pandey

Final year undergratuate

Civil Engg.

IIT  Bombay

[Asadur Rahman]

You may check

1) ANODE and BNODE for individual link. Sometimes by mistake the same NODE is coded as ANODE for different links which may not correct for network, or vice versa.

2) You may NOT set the  MAX_CIRCUITY_RATIO as ZERO, because many times it is not realistic. All the travelers cannot directly go to destination. I believe I had some issue after setting the MAX_CIRCUITY_RATIO as zero. So you may try some other value based on your model.

3) You are right that the Converttrips the Walk mode is different. But I am not sure why in Router it is changed. You can check at Page 23 of the documents, where mentioned

Travel mode This must be one of:

0 = car

1 = transit

2 = pedestrian

3 = bicycle

4 = non-transportation activity

You can try this. And see if there is any update.

Hope it helps!

Asad.

[Venktesh Pandey]

Oh.
So is it not possible to have a node acting as only B_NODE for all links coming to it, even when the links have opposite direction lanes activated?
I thought that BA direction lanes meant reverse direction flow is allowed too.

I'll try changing these and will update.
Thanks for help :)

[Roden, David]

BA direction does mean reverse direction is available.  Lane-connectivity may be a problem.  Have you checked the link-use codes? 

 

David B. Roden, P.E.

Senior Consulting Manager

AECOM

2101 Wilson Boulevard

Suite 800

Arlington, VA  22201

david...@aecom.com

703-340-3069

 

[Venktesh Pandey]

Oh indeed it was link-use.

TransimsNet was changing the use code of my input external link from ANY to 'WALK only'.

I changed it to find that even my path building problems are gone now :)

But curious to know why would transimsNet change the USE code of links?

And still what were these new MODE types used in router problem files as mentioned before.

Thanks for help :)

Venktesh Pandey

Final year undergratuate

Civil Engg.

IIT  Bombay