Home - Blog - How does Flock Freight calculate emissions savings and the environmental impact of trucking?


How does Flock Freight calculate emissions savings and the environmental impact of trucking?

09.01.2020 | By Katherine Stolin | 5 min. read
Note: We’ve updated the way we calculate emissions since publishing this blog post. Read our recent blog post to learn how our new emission calculations help us prioritize accuracy and transparency.


Learn how we determine the environmental impact of FlockDirect and other shipping modes

Table of contents

How does Flock Freight calculate shared truckload’s emissions savings?

The short answer
  1. Shared truckload shipments remove the need for 60% of the fuel that less-than truckload (LTL) carriers use for hub-and-spoke operations.
  2. A shared truckload drives, on average, a 20% longer route than a regular point-A-to-point-B truckload shipment.
  3. 60% – 20% = 40% savings in fuel and fuel emissions.
The long answer

In the supply chain world, being “green” is a major topic of discussion. Emissions targets, public image, and fractional environmental footprints are all surfacing to the forefront of company goals and missions across industries. In the freight industry, many different solutions promise a “greener” track to delivering goods, but it can be tough to decode exactly why and by how much these freight options – that claim to be sustainable – actually reduce environmental impact.

At Flock Freight®, our specialty in shared truckload (STL) service is inherently better for the environment primarily because it slashes greenhouse gas emissions that are caused by freight shipping. In an effort to make sustainability easier to understand, we want to be completely transparent and inform you exactly how we calculate our emissions savings. 

Before we explain, it’s important to understand a couple of key concepts. The first concept is carbon dioxide equivalents (CO2e). When a gasoline- or diesel-powered vehicle emits exhaust, the atmosphere becomes exposed to many different things – not just carbon dioxide. When you see “CO2e” tied to our emissions savings, that means we’re calculating the impact of all different types of pollutants that come out of a truck’s exhaust and wrapping them up into a comprehensive metric that accounts for their Global Warming Potential (GWP). If you want to learn more about GWP, you can read about it here. 

When shipping freight through shared truckload service, you reduce greenhouse gas emissions by approximately 40%. The way we arrived at this number is by assuming that emissions correlate closely with diesel consumption and by benchmarking fuel consumption from LTL carriers.  Based on work from various sources, we learned that the distribution of fuel consumption when shipping LTL is:

  • 40-70% Pickup & delivery (P&D).
  • 20-30% Shuttle (transits between the terminals and hub within a market geography).
  • 20-40% Linehaul (long-distance transport between markets).

Based on this logic, we assume that if a group of LTL shipments makes up a shared truckload, they would not require the P&D or shuttle portions of this journey. They would, however, incur some additional fuel expense, specifically:

  • Fuel associated with idle time at pickup and delivery
  • Fuel associated with out-of-route miles
  • Penalty for less than 100% utilization of linehaul trailer (We make the conservative assumption that LTL linehaul trailers are 100% utilized, while shared truckload trailers average 100% utilization.)

The table lays out an illustrative example about four LTL shipments that get moved between two markets 1,300 miles apart as part of a shared truckload. Since this analysis makes multiple assumptions, we kept all assumptions as conservative as possible, specifically using the largest percentage of linehaul fuel expense in the range. Additionally, we assume penalties for (a) idle time, (b) out-of-route mileage, and (c) trailer utilization. The result is fuel consumption of 600 gallons of fuel, or a 40% savings versus LTL.

Fuel Use (Gallons) Explanation 
1,000 Total fuel consumption to move four LTL shipments from Market A to Market B
–  400 Fuel required for pickup at origin points
–  200 Fuel required for transit from origin terminal to hub and from destination hub to terminal
=   400 Fuel required for linehaul (1,300 miles / 6.5 MPG)
+  40 Allotment for idle time at pickup and delivery (10% of linehaul)
+  80 Allotment for 20% out-of-route mileage of shared truckload route (20% of linehaul)
+  80 Penalty for 80% trailer utilization (20% of linehaul)
=   600 Total fuel consumption of moving shipments as a shared truckload


From here, we assume every STL shipment’s emissions savings occur because it did not move as an LTL through the hub-and-spoke network. Assuming that the STL shipment replaced an LTL one, we use the following figures to calculate emissions:

  • Average mileage of a shipment: 1,000 miles.
  • Average fuel economy of a 53’ truck: 6.5 miles per gallon.
  • CO2 equivalent of a gallon of fuel: 19.6 pounds of CO2e per gallon of fuel.

We use the EPA-defined CO2e for a gallon of fuel, which you can explore here to see how fuel savings equate to different environmental impacts.

Calculating exact emissions is a difficult task that can never be done with 100% accuracy unless it’s being measured in a lab. Is the calculation we use backed by real data that is constantly being monitored? Yes. Is it perfect? No. We believe that making the decision to be environmentally responsible should be backed by an understanding of how that impact is happening and the magnitude that you’re contributing to make a difference. 

Flock Freight is constantly working to educate and inform our customers across the industry about how they can produce fewer greenhouse gas emissions in their supply chains. It is without question that shared truckload makes strides to help supply chains become “green.” This belief is part of the reason we’ve been certified as a B Corporation, with a central focus on using business as a force for good.

As we tirelessly work to bring environmental stewardship to the forefront of the freight industry,  we encourage every shipper – whether you’re a small business or a Fortune 500 corporation – to take part in our mission: To reimagine and reinvent the freight industry by relentlessly eliminating waste and inefficiency.  

How does Flock Freight calculate carbon offsets for FlockDirect shipments?

The short answer

We calculate carbon offsets for a FlockDirect™️ shipment by estimating the emissions resulting from the distance a 53-foot tractor/trailer travels to move Flock Freight shipments.

The long answer

To estimate the emissions needed to offset a FlockDirect shipment, we make a few assumptions:

  • The shipment is moving on a full 53-foot dry van.
  • Fuel economy for a 53-foot dry van is 6.5 miles per gallon.
  • 53-foot dry van maximum load capacity is 45,000 pounds.
  • Shipment’s share of the total weight that the trailer moves accounts for the corresponding share of the truck’s emissions.

We use a simple calculation to measure the emissions that come from a particular FlockDirect shipment:

emissions = a shipment’s traveled mileage x fuel economy x carbon intensity of fossil fuel x share of weight

This information comes from real FlockDirect shipment data. Once a shipment moves, we estimate the amount of emissions that particular shipment caused. Next, we subtract that shipment’s emissions from our stock of carbon offsets, rounded to the nearest metric ton. (Our average shipment equates to about one metric ton of emissions.) 

If a FlockDirect shipment moves with other FlockDirect shipments on a shared truckload, we attribute the emissions of each individual shipment to the share of weight that shipment occupies (out of 45,000 pounds).

Every carbon offset we have in our stock comes with a serial number that Carbonfund.org has retired off of the American Carbon Registry on our behalf. We can provide both the certification and serial number for the offsets of any particular FlockDirect shipment upon request. 

How does Flock Freight calculate the environmental impact of other shipping modes?

How we determine the annual trucking emissions for the LTL, partial, and truckload (TL) shipping modes:

1. First, we assume the following size estimates of each market:

  • LTL: $65 billion
  • Partials: $5-20 billion
  • For-hire truckload: $360 billion

2. Second, we limit the scope to these three modes, excluding private fleets and other shipping methods

3. Next, we calculate the total market value of these three modes, which computes to:

  • If we assume a partial market worth $5 billion: $65 billion + $5 billion + $360 billion = $430 billion
  • If we assume a partial market worth $20 billion: $65 billion + $20 billion + $360 billion = $445 billion

4. Then, we divide the value of each mode by the total market value, which works out to approximately:

  • For a partial market of $5 billion:
    • LTL: 65 ÷ 430 = 15%
    • Partials: 5 ÷ 430 = 1%
    • TL: 360 ÷ 430 = 84%
  • For a partial market of $20 billion:
    • LTL: 65 ÷ 445 = 15%
    • Partials: 20 ÷ 445 = 4%
    • TL: 360 ÷ 445 = 81%

5. Finally, we multiply the market percentage of each mode by 437 million (the approximate amount of carbon that medium- and heavy-duty freight trucks emit every year) for annual trucking emissions of:

  • LTL:
    • For a partial market of $5 billion: 15% ✕ 437 million = 65,550,000 tons of CO2
    • For a partial market of $20 billion: 15% ✕ 437 million = 65,550,000 tons of CO2
  • Partials:
    • For a partial market of $5 billion: 1% ✕ 437 million = 4,370,000 tons of CO2
    • For a partial market of $20 billion: 4% ✕ 437 million = 17,480,000 of CO2
  • TL:
    • For a partial market of $5 billion: 84% ✕ 437 million = 367,080,000 of CO2
    • For a partial market of $20 billion: 81% ✕ 437 million = 353,970,000 of CO2

From these calculations, we deduce the annual trucking emissions of the LTL, partial, and TL freight modes to be:

  • LTL: 65 million tons of CO2
  • Partials: 4-17 million tons of CO2
  • TL: 353-367 million tons of CO2

Learn more about the environmental benefits of FlockDirect today.