Seems like a simple optimization on max tons/hr...however...

Question

Hi there,

I have what seems like a relatively simple problem but there's a catch that I can't seem to figure out a workaround with Network Analyst.  Each road segment is coded with a maximum Tons/hr value.  If I maximize on this, It would generate the proper route that adds up all the segments of the route to give me the maximum tons/hr.  All roads are classified as either a 63.5 tons, 55.5 ton or 43.5 ton road.  If the route that is generated has any segments that would be 43.5 tons, then the whole route would need to be classified as a 43.5 ton road.

It's a bit confusing for me to try and maximize on tons/hr keeping in mind that if any of the segments have a lower ton rating, then all the segments would get tagged as 43.5 and the max ton/hr value would be much less.

Hopefully i've explained this enough for someone to try and understand.  Would greatly appreciate any feedback or ideas on this problem.

Thanks,

Nick

JaySandhu · Answer

Can route capacity (Gross Vehicle Weight) be accomodated by ArcLogistics when determining "optimal" routes?

Yes. See the note on "Capacities" where it talks about Route properties.
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Vehicle_routing_problem_analysis/00470000004v000000/

Jay Sandhu

CharlesDavis · Answer

Maybe I could paraphrase nickdemerchant's problem with the following example:

Two route options are available to transport goods from origin A to destination B.  The first route uses short-cut over a weight restricted bridge, takes 1.0 hours, and the truck can carry 25 tonnes of payload.  The second route avoids the weight restricted bridge, takes 1.25 hours and the truck can carry 35 tonnes of payload.  Which is the best route to take?

Using the least time method, you would select the first route as the best option.  However, given the increase in payload, the second option is the most effective route.  The first route delivers the goods at the rate of 25 tonnes/1.0 hours = 25 tonnes/hour.  The second route delivers the goods at the rate of 35 tonnes / 1.25 hours = 28 tonnes/hour.

Can route capacity (Gross Vehicle Weight) be accomodated by ArcLogistics when determining "optimal" routes?

JaySandhu · Answer

Nick,

You are trying to describe a behavior on how the solver should work to solve your problem.

But you are not describing your problem in detail. So I am going to guess that what you are trying to do is solve "The Transportation Problem". That is, you have a set of supply locations, a set of demand locations, capacity on the road network and the goal is to minimize shipping costs of moving a given amount of goods through the capacitated network.

If this sounds like what you are trying to do and you are not famillar with "The Transportation Problem", I would suggest doing a web search. A way to sovle it with linear programming is described here:
http://extension.oregonstate.edu/catalog/pdf/em/em8779-e.pdf

If this is what you were trying to do, then you can use the above methodology to use the OD Cost matrix to compute the travel costs, export them to an appropriate LP and solve. An example of this is here:
http://resources.arcgis.com/gallery/file/geoprocessing/details?entryID=C4E79AE3-1422-2418-88B2-008CC5F9D24F

The above demonstrates how to use the LP approach for School allocation. You will have to modify it to solve your problem instance.

Regards,
Jay Sandhu

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