Ignore One-way Restriction in Network Analyst Backhaul Optimization

[RichThomas2]

This question pertains to Network Analyst Backhaul Optimization: How can I configure it to ignore the one-way travel direction restriction? The reason I need this is because placement of fiber optic cable does not depend on the travel direction of vehicles, and the routes being generated are resulting in unnecessary length due to divided highways causing u-turns. Thank you in advance

 networkanalyst backhaul optimization#

[HunterWest]

Hi Rich,

Are you using Streetmap Premium for the input Network Dataset, or something else? The easiest way to avoid this is probably to adjust a couple of the Analysis settings in your Closest Facility Layer. The first few that I would try:

1) If you haven't already, uncheck the box for "Use Hierarchy". We likely don't need to for fiber routing.

2) There's a setting that asks how you want to treat U-turns at junctions. Try selecting the option for "Don't Allow" and see how that changes the results. I've had success with it, but you'll just have to see if it works with your dataset or if it just creates 3 left turns instead of a single U-turn.

If that doesn't fix the issue then we will probably have to do some edge consolidation, which can get more complicated. Let me know what happens.

Thanks,

Hunter

[RichThomas2]

Thank you for your ideas Hunter. Unfortunately, I tried them both and neither achieves what I was looking for. 1) The "Use Hierarchy" option merely turns on/off the preference to use bigger roads rather than smaller ones. 2) I have not seen any difference in the routes generated with or without U-Turns allowed, but anyway U-turns are a result of following the direction of one-way streets, which is what I want to ignore. I appreciate your trying to help anyway. Rich

[HunterWest]

Yea, the Hierarchy suggestion is just a good practice for fiber routing in general and I thought it may help since it tends to be higher tier highways and such that have one-way roads with large medians. 

What sort of Network Dataset are you using? If you have the source data available, then you should be able to just build a new Network Dataset off of that data that has no Travel Modes attached to it. Not having a Travel Mode should mean that it does not recognize any field that would otherwise indicate a direction restriction, and *should* allow you to traverse any street segment in any direction without issue.

Does it make sense what I'm suggesting? Let me know if you need me to elaborate.

[RichThomas2]

Thanks again Hunter. Yes the Hierarchy is good for fiber optic cable routes. I am using ESRI's StreetMap Premium for ArcGIS Desktop which comes with a pre-built Network Dataset. As far as I've found, it cannot be edited or copied because it is licensed, so I don't think I can build a new Network Dataset without Travel Modes.

However, I had a revelation that solved my problem with one-way streets. In the Closest Facility Analysis Settings Restriction there are choices for Driving an Automobile, Driving a Truck, Walking, etc. I thought you had to choose one of those modes, but my revelation was that you don't have to pick any of them, and it was those choices that were causing the restriction on one-way travel. With none of those selected it is not restricted to one-way travel and successfully routes in any direction. However I do now have to watch out for it routing on walking paths, because it is no longer restricted to where an automobile drives, and walking paths are generally not where you could place fiber cable.

[HunterWest]

That's great info, thanks for sharing. Not having to select a travel mode is even better than creating a new Network Dataset that doesn't have any!