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10-31-2012 08:38 AM
New Contributor III
I'm trying to account for bridge clearances.  But I'm not sure if they would be a restriction or an added cost.  Any ideas?!
Tags (2)
5 Replies
MVP Emeritus
Just a WAG (wild *** guess) but I think a restriction would be the way to go.

Think of it this way; if you add a cost all that does is give the solver a reason to minimize the cost.  But what if it can't?  Lets say a route for a vehicle is restricted due to barriers of some sort.  It would then route under/over the bridge in question just because it could.  The cost is what it is.  But the real problem is you routed a truck over a bridge that can't support it's weight or under one that isn't tall enough for the load to pass.  Ouch...

A restriction like XXX,XXX lbs or XX feet would ensure you from what I like to call a 'resume generating event'...
That should just about do it....
New Contributor III
Just a WAG (wild *** guess) but I think a restriction would be the way to go.

Think of it this way; if you add a cost all that does is give the solver a reason to minimize the cost.  But what if it can't?  Lets say a route for a vehicle is restricted due to barriers of some sort.  It would then route under/over the bridge in question just because it could.  The cost is what it is.  But the real problem is you routed a truck over a bridge that can't support it's weight or under one that isn't tall enough for the load to pass.  Ouch...

A restriction like XXX,XXX lbs or XX feet would ensure you from what I like to call a 'resume generating event'...

OK, that makes sense.  But, when I have it entered in, how do I account for the different clearances? Some are 14ft up to 17ft.  For instantance.  A truck has a height of 15.  It can go under bridges 15ft 1in or higher, but not the 14ft 11 in or lower.  But as a restriction, it will block all of the bridges, won't it?
Esri Regular Contributor
You should model it as a parameterized restriction. At solve time you can set the height of the vehicle and then the restrictions will be used appropriately. Read more about it here in the section titled "Parameters for modeling vehicle characteristics":

http://resources.arcgis.com/en/help/main/10.1/index.html#/Using_parameters_with_network_attributes/0...

You can also look at how this is done in the tutorial network dataset for San Diego which has a height as well as length restriction with parameters.

Jay Sandhu
New Contributor III
Thanks Jay.  I will try that and see if it helps!
New Contributor III
Jay-  After reading through that material, I won't be able to do utilize the Restriction Usage, as I am using 10.0, not 10.1.  I will have to do some more reading into the parameters on cost attributes.