topic VRP - Attempting to use Order Pairs for Bus Routing in ArcGIS Network Analyst Questions

VRP - Attempting to use Order Pairs for Bus Routing

KJanssen — Wed, 18 May 2011 02:33:35 GMT

My bus routing problem has been doign my head in. The tools don't seem to quite match what I want to do exactly.

Simply I have 75 schools and 1700 students eligible for School Bus travel. Each student is pickup on the network and transported to their best match school based on age, gender Etc.

I have got a model that can create the routes for individual schools (based on selections on the student and schools layers) however I want buses to be able to transport students going to different schools. This will mean there are less routes overall and improve efficiency.

I have been attempting to use the Order Paris Network Object however when I try and solve it this error is returned (a snippit).

Warning: Order Pairs (FirstOrderName = "7204", SecondOrderName = "Coastal Taranaki School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7211", SecondOrderName = "Coastal Taranaki School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7224", SecondOrderName = "Coastal Taranaki School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7277", SecondOrderName = "Coastal Taranaki School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7464", SecondOrderName = "Rahotu School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7519", SecondOrderName = "Rahotu School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7526", SecondOrderName = "Rahotu School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7528", SecondOrderName = "Rahotu School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7786", SecondOrderName = "Matapu School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7822", SecondOrderName = "Matapu School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7850", SecondOrderName = "Auroa School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7851", SecondOrderName = "Auroa School") has a SecondOrderName value for an order that is already paired.
Warning: Order Pairs (FirstOrderName = "7861", SecondOrderName = "Auroa School") has a SecondOrderName value for an order that is already paired.

It appears to me that you cannot have the same second order pair for different first order pairs. This is clearly a problem when I am trying to route multiple students to the same schools. Does every Order Pairing need to be unique?

Any ideas? Am I even on the right path?

Re: VRP - Attempting to use Order Pairs for Bus Routing

NaAn — Wed, 18 May 2011 17:12:45 GMT

Hi Kurt,

You will need a copy of the school delivery order for each pair. For instance,

(FirstOrderName = "7204", SecondOrderName = "Coastal Taranaki School 1")
(FirstOrderName = "7211", SecondOrderName = "Coastal Taranaki School 2")
(FirstOrderName = "7224", SecondOrderName = "Coastal Taranaki School 3")
(FirstOrderName = "7277", SecondOrderName = "Coastal Taranaki School 4")
(FirstOrderName = "7464", SecondOrderName = "Rahotu School 1")
(FirstOrderName = "7519", SecondOrderName = "Rahotu School 2")

Thanks.

Anna

Re: VRP - Attempting to use Order Pairs for Bus Routing

KJanssen — Thu, 19 May 2011 03:26:15 GMT

Thanks Anna. I had actually figured this out after I did the post. Thanks though.

Now I have issues allocating bus routes. Ideally I wanted this to be dynamic so it would create new routes on the fly as it needed them. I know the tool is not designed for this however.

We do not have a set number of buses. The project is at a strategic/research level at this stage and I am trying to work out the best lowest cost options. In an ideal world when we know where all the kids are to be picked up and where they are going so how best can we allocate buses to fulfil their needs.

Cheers

Re: VRP - Attempting to use Order Pairs for Bus Routing

NaAn — Fri, 20 May 2011 21:55:11 GMT

Hi Kurt,

VRP solver will use the minimum number of vehicles which can minimize the total cost. It does not need to use all vehicles included in the problem. Therefore, when you are not sure how many vehicles are needed, you are free to add more vehicles in the problem and let the solver determines the optimal number.

Thanks.

Anna