Landfill Insights: Planning along the ‘desire path’

Understanding supply, demand and desire can help optimize your facility’s schedule.

Bolton

Most businesses or services, including your landfill, transfer station, material recovery facility or organics facility, started with a plan. You can call it a service plan, a business plan or even a marketing plan. Regardless of the name, the idea was to provide what your customers want—and what they’re willing to pay for.

This is no small thing. You’ve invested millions in turning that plan into a reality. Sure, in the big picture, we could be talking about the facility itself. If you build it, they will come. At least you hope they will, especially when we’re talking about the cost of providing the service you hope to offer.

Today, however, I’d like to move a bit further out of the box and talk about something else—the theory of “desire path.” It’s the idea of listening to—and watching—customers to find out what they want and then providing it, rather than the other way around.

In the world of economics, this is the difference between push and pull.

In push economics, the supplier starts with a product and tries to convince the customer to buy what the supplier is selling. Think “pushy” salesman.

But in pull economics, the customer’s desire sets the tone for what the supplier will supply. This concept applies not only to products but to other things as well. This is not just a buy/sell concept. It applies much more broadly to the world of supply and demand.

Here’s a classic example that might surprise your concept of supply and demand.

So, the story goes: It’s becoming more commonplace to construct buildings, say, at a college campus, but to then delay construction of the sidewalks for a year. Then, wherever people wear a path across the grass, that’s where the sidewalks are built. This is a clear picture of supply and demand as it applies to infrastructure. It’s also a great example of designing a system that meets the needs of the users, rather than the other way around.

This design approach builds upon what urban engineers refer to as a “desire path.” This can be a frustrating issue for planners because that sidewalk layout that looked so great on a set of plans—or even during the construction phase—might be ignored in favor of some shortcut path.

This represents the critical blending of engineering and empirical evidence.

In my previous life, I spent several years operating heavy equipment. Some of that time was on a bulldozer, pioneering roads through the hills, over ridges and across swales. The idea was to provide efficient access from point A to point B. We’d survey the alignments using an Abney level or inclinometer. We’d set stakes and flag the route. That was the engineering side of the equation.

But we’d also rely heavily on observing—and often following—old, worn cow trails. One of the old timers on our crew referred to this as “following Bessie.” You see, cattle naturally will follow the easiest slope. They will cross ridges in the most efficient saddles. Without knowing the technical terms, we were using the theory of desire path—old Bessie’s desire path.

This concept has many applications in the solid waste business. We’ll look at an example that applies to any facility where vehicles (i.e., customers) enter the site to drop off waste or recyclable materials.

Consider your days and hours of operation. Your facility is set up to provide a specific service, at specific times, on specific days. The most obvious schedule is for receiving waste or recyclables, but your facility may do many other things, like sell compost, mulch or woodchips. Maybe you provide a wide range of recycling.

Whatever services you provide, it’s likely the associated schedules have been in place for a long time … maybe always. And, based on your daily workload, you probably haven’t given them much thought. Your crew and your customers know the routine, and every day it just works. But does it really?

Look at this chart. It shows the inbound tonnage and inbound traffic count for a typical waste facility during an average weekday.

It’s the classic camelback tonnage pattern.

This is something we often analyze when conducting an operational review of a landfill, transfer station or any other facility that has inbound tonnage.

Hourly tonnage (the blue columns) peaks in late morning as route trucks finish up their first round, and then there is another peak after lunch as they complete their second. Doesn’t matter if they are hauling waste, recyclables or green waste.

We also see that the number of vehicles (the red line) increases later in the day as various contractors and other self-haul vehicles wrap their last loads and try to beat the clock. More vehicles, but less tonnage.

The hours of the operation are from 6 a.m. to 8 p.m. Fourteen hours during which the facility is staffed and open for business. That’s your product availability. But let’s look more closely at your customers’ desire path. That is: What part of your facility’s schedule are the customers using?

Observation 1: In the first two hours, the facility receives just over 30 tons of material but, more importantly, only a handful of vehicles. Closer inspection reveals these are trucks that were preloaded the day before, or maybe front-loader trucks just finishing their first round with trash or recyclables.

Question 1: Does the facility need to be fully staffed for those first two hours, or could those few drivers be given a key or gate code and trained to dump in the right place, unattended? What’s the harm in your regular commercial customers (i.e., several packer-truck loads) sitting in a pile for a couple of hours until the facility crew shows up?

Observation 2: At 4 p.m., the hourly tonnage is only 15. Then it drops quickly until the facility closes at 8 p.m. In fact, during the last three hours of the day (from 5 p.m. to 8 p.m.), the facility receives only 13 tons of trash.

Question 2: Is the revenue from 15 tons of material enough to cover the cost of the staff and equipment required to keep the facility open until 8 p.m.? Further, where would those final 15 tons of material go if the facility was closed during those late hours? Likely those customers would simply come in earlier, or they’d hold it over until the next morning. The point is, you wouldn’t lose the revenue, it would just squeeze into a shorter workday—your crew’s shorter workday.

Adjusting the weekday schedule to 8 a.m. to 5 p.m. would reduce the operating day by five hours, perhaps eliminating the need for a staggered shift while still meeting the “desire” of most customers.

Sounds pretty good, huh? But hold on because we’re not finished. Because this facility is open seven days a week, I’ve also included a similar chart for a typical weekend day.

Compared with an average weekday, the weekend shows more traffic and less tonnage.

Observation 3: The early morning and late afternoon are slow times. Only 16 tons of material came in between 6 a.m. and 9 a.m. and between 4 p.m. and 8 p.m.

Question 3: Why is the facility even open three hours before 9 a.m. and four hours after 4 p.m.? By simple inspection, we could reduce its operating day by seven hours, and only impact a handful of customers and about 16 tons of material. And again, it’s likely those customers would simply adjust their schedule to come in during the new hours. You wouldn’t lose the revenue; it would just squeeze into a shorter workday—your crew’s shorter workday.

Observation 4: At most waste facilities, Saturdays are slow, and Sundays are slower.

Question 4: Taking this concept a bit further, would it be possible to close on Sunday and push those customers to Saturday? Well, you won’t know until you split out the Saturday and Sunday data and determine your customer’s desire on those individual days.

By adjusting the facility’s work schedule to match customer desire, there would likely be no lost revenue, but plenty of cost savings.

The pattern for tonnage and vehicle count also will vary seasonally. That means your operating schedule could need to adjust accordingly. In northern climates, the winter can mean snowy conditions, icy roads, fewer daylight hours, less green waste and a drop off in construction activity. That all translates to less tonnage or a shift in arrival times.

This idea of observing what customers want and then trying to provide it is nothing new. Retailers do this all the time, and many companies have truly made a science of understanding supply and demand. You’ve seen how sidewalks can be optimized under the theory of desire path and even how waste and recycling schedules can be optimized under that same concept.

There are likely dozens of opportunities to adjust your operation to better match customer desire. It’s just a matter of observing, asking and listening to your customers. When you can integrate the engineering and the empirical, your customers will be satisfied, and you’ll save time and money.

The theory of the “desire path”—it’s worth thinking about.

Neal Bolton is president and lead engineer for Blue Ridge Services – Montana Inc., a Hamilton, Montana-based solid waste consulting company. He can be reached at neal@blueridgeservices.com.

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