Snow Plowing and Salting Routing

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12-13-2016 10:18 AM
NathanFidler
New Contributor II

Hi everyone,

I am really hoping that there is someone out there who has a similar problem to me and/or can help me find a solution to this problem.

I work for a large municipality and my primary role is to create and maintain our mapping datasets. This question is specifically related to snow plowing and salting operations that we undertake.

In the past, the standard practice has been to create beat maps for each of our pieces of equipment for our winter operations. These maps would generally consider the beat length, distance from the yard/depot, type of equipment, road class etc. Our maps have always been fine, but we are now running into issues with our contractors related to our choice of routing. Typically we would suggest areas of the beat where they should start, but we would never give turn by turn directions, or show directional lines on a map. 

This lack of routing information has consistently proven to be inefficient and now I am tasked with coming to a solution to this problem. I have been asked to route each piece of equipment in our contracts - we are talking close to 500 different routes. My predecessors in my role would draw lines on our maps to indicate the routing, but this proved to be incredibly time intensive, and when our routes change due to the addition of new streets/additional pieces of equipment, etc, the routing has to be done again. 

I do not have a license to the Network Analyst extension, however, if the case could be made, I am certain our department would cough up the cash to make it work, but first I NEED to know if this extension can do what I am looking for. 

This is the typical scenario:

I create a route for a snow plow (a list of streets that must be completed by this piece of equipment); ideally it only makes right hand turns (not a deal breaker if it doesn't); it must leave from the yard to the designated start of the beat and it must go on every street identified on the beat, and it must travel on each side of the street (i.e. to clear the driveways for each side of the street). Ideally it would create some sort of line routing that can be read on a map for the operator to see in the cab of his vehicle - even better would be the ability to export the route and upload it to something like Google Maps or a Tom Tom where the route can be dictated to the operator. 

I realize that I may be asking for something that does not exist, but hey, it's 2016 and (almost) anything is possible!

Thoughts? Ideas? Alternative suggestions?

I appreciate it!

5 Replies
EricRodenberg
Esri Contributor

Nathan,

Yes I believe that Network Analyst can help you.  You will have to solve for multiple problems using Network Analyst which is not out of the ordinary.  It just might require multiple passes.

You'd need to define service areas using the Services Area Solver.  The Service Area will allow you to balance the number of streets, major minor etc so that each dirver roughly has equal coverage.

Then you would run the Vehichle Routing Problem on each service area section and you can weight your major roads so they are attened to fist. VRP was built for deliver orders that assigned to a set of routes but the order in the case might be point that are dropped on either side of a street at both ends.  

The solver will honor vehilce capacities, driver specialites and delivery windows and you can configure to have the routes generated so you hit the order points on the right side of the street.

There may be other factors to consider like closest facility if you have salt barns spread accross the city.  Your driver may be closer to another salt barn and factoring thier vehicle capacity would allow you to take into account a barn that my not be the driver's originating facility but a closer stop to where they are at the time they are expected to be reloading.

As for GPS,  we are coming out with the ability to upload custom routes to Navigator for ArcGIS.  Navigator is a productivity app that provides on or offline turn by turn directions to an Andrioid, iOS or Windows phone.  Not sure when that capability will be released but it is coming.  

Where are you located, I can get you in contact with an Esri Rep if you are in the US and I can get my thoughts to a technical resource on the Esri City/County Government team so they can guide you on what you need to do this.

Eric Rodenberg

Eric J. Rodenberg | Solution Engineer Transportation Practice
Esri | 7775 Walton Pkwy, Suite 270 | New Albany, Ohio 43054-8202 | USA
T 614-933-8698, ext. 5503 | erodenberg@esri.com | esri.com
NathanFidler
New Contributor II

Eric,

Thank you so much for taking the time to respond to my question in such great detail. I do not have any experience using the Network Analyst Extension, but it does sound like it could possibly do what we are looking for.  I am with the City of Toronto.

To add to this, I will specify a few more criteria that we would have to incorporate.

"You'd need to define service areas using the Services Area Solver.  The Service Area will allow you to balance the number of streets, major minor etc so that each dirver roughly has equal coverage."

We have separate contractors for our road classifications. One contractor would do Arterial and Collector Roads (usually not on the same beat); and we have contractors specifically for Local roads - this is done because each road class gets a specific minimum level of service depending on the winter event - i.e. 5 cm of snow triggers all the arterial and collector routes, but 10 cm triggers the local routes.

Furthermore, we have already determined what our routes are based on the truck capacity and spread rates of the vehicles for our arterial and collector routes. These beats generally do not change, as it is uncommon for new major roads to be built or expanded on, as they are essentially the framework of our transportation network. Our contracts last 7 years and it is when they are up for renewal that we can request additional equipment (to shorten the routes, and then redesign the beats). We are currently in year 2 of 7, so we won't be looking at changing this right away. 

As for our local beats; we know the number of pieces and types of equipment we have. We also try to design the beats so that pregnant corners, dead ends and cul-de-sacs are serviced by either front end loaders or bi-directional tractors, as they clear the snow much more efficiently. Compounded with this problem is that we try to make beats that are further away from the depot shorter than the ones that are closer to the depot - essentially we are trying to offset the travel time across the district so that the entire operation ends at around the same time.

Sidewalk clearing is also another issue for us. We have sidewalk beats where we have identified the sidewalks that are considered "high volume" and "low volume". It is not uncommon for us to start our operation doing only the high volume streets, then switch to the low volume streets mid way through, then back to high volume - again, this trigger is dependent on the snowfall accumulation. Something on the fly that could switch between high and low volume for us would prove to be invaluable. Furthermore, the direction of a road (one-way) does not apply to sidewalk machines, as it may require a pass on both sides of the street, so routing here is not dependent on the actual road itself, it is dependent on the presence of sidewalk.

"There may be other factors to consider like closest facility if you have salt barns spread accross the city.  Your driver may be closer to another salt barn and factoring thier vehicle capacity would allow you to take into account a barn that my not be the driver's originating facility but a closer stop to where they are at the time they are expected to be reloading."

As I mentioned, for all of our roadway salting operations, the beat lengths are predetermined and are calibrated so that they can hold enough salt for their beat; furthermore, the contractors are not allowed to go to a salt dome that they do not initially operate out of (this is for city audit and accounting purposes). That being said, sidewalk machines can and do run out of salt during their operation and they frequently have to stop and wait for nurse trucks to come and fill them up. We have 1 nurse truck for every 3 sidewalk machines, so I suppose we could theoretically determine at what point along the route we can expect the machine to run out of salt, and have a designated drop off area and route for our nurse trucks to follow. Would this be possible to do as well?

Essentially, we are not really looking at changing our existing beats, we are looking at how to properly route our existing beats to maximize our efficiency. Snow plowing is massive undertaking for us and it costs us millions of dollars a year. If we could even optimize 5% of our routes, it would translate into significant cost savings. 

The real crux of our problem here is that we rely on paper maps for our contractors to follow. Despite the fact that we have our routes identified for each piece of equipment, we have never been able to physically outline the direction of travel for our operators to follow. We need something that can be put into a GPS that is in the truck with the operator. Even better would be something that could also incorporate the current state of traffic/road closures/ability to skip streets and come back to them later (due to parked cars, police activity, etc). I'm sure you can recognize the benefit that this would have for us, not only for our residents, but also for our department operational costs, potential legal costs (if streets are missed), etc. 

Does the technology exist for this type of dynamic system we need? Even if we could get basic routing, with turn by turn directions, and directional lines on our paper maps, this would be a significant improvement.

Cheers,

Nathan

EricRodenberg
Esri Contributor

Sanne, This is certainly one of the most difficult tasks to solve with Network Analyst. The type of route you are trying to accomplish is called a Postman Tour<https://en.wikipedia.org/wiki/Route_inspection_problem>. Essentially the drivers job is to pass every lane on a street using the shortest route possible. The drive has to pass each street once and then return to the origin. Esri does not have a solution for this type of route solver out of the box. It can be accomplished by setting points at each edge and configure a route solver to touch each point. Not a very practical or easy to accomplish work around but can be done. We also have several business partners that have solutions. We can certain optimize routes and stage materials. I think you should look at our partner solutions for a route solver that supports the postman tour

I believe RouteSmart technologies has a solution that utilizes ArcGIS and they have solutions specifically for snow plows.

Eric J. Rodenberg | Solution Engineer Transportation Practice
Esri | 7775 Walton Pkwy, Suite 270 | New Albany, Ohio 43054-8202 | USA
T 614-933-8698, ext. 5503 | erodenberg@esri.com | esri.com
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EricRodenberg
Esri Contributor

Nathan,  this is certainly a complex problem,  I've looped in some folks from Esri Canada, so you should be expecting someone to contact you directly to help and provide direction.

Eric J. Rodenberg | Solution Engineer Transportation Practice
Esri | 7775 Walton Pkwy, Suite 270 | New Albany, Ohio 43054-8202 | USA
T 614-933-8698, ext. 5503 | erodenberg@esri.com | esri.com
ScottSandusky
Esri Contributor

Hi Nathan and Eric,

Nathan, I just want to be completely transparent with you and the City or Toronto.  The snow plow routing problem is known in the algorighm world as the Arc Routing problem.  https://en.wikipedia.org/wiki/Arc_routing  Arc Routing is not something that Network Analyst was designed to support.  That being said, there are organizations that have configured workflows for solving snow problem route analysis using the Network Analyst extension.  It’s just that the workflow (Eric outlined one possible option) and limitations (I didn’t want to misrepresent Network Analyst) have to be understood.  Esri does have partners like C2Logix and RouteSmart with Arc Routing solutions.

Thanks, Scott