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Flock Freight’s updated emission calculations: raising the bar on sustainability reporting

04.06.2022 | By Katherine Stolin | 5 min. read

How our new emission calculations help us prioritize accuracy and transparency

In this blog

Why we updated our emission calculations

Setting a reporting standard for shipping is key to assessing and improving corporate sustainability. Because freight transportation contributes heavily to every business’s environmental impact, efforts by shippers to track and reduce greenhouse gasses (GHG) are especially important.

Measuring supply chain emissions and publicizing footprint reduction tactics aren’t yet standard procedures, but businesses must embrace this shared responsibility to see environmental impact improve across shipping operations. 

Sustainability remains at the forefront of our mission, and as Flock Freight has grown, so too has our ability to record, analyze, and increase the accessibility of our emissions data. Using the most credible information available to us, we decided to update our methods for tracking our shared truckload (STL) solution’s environmental impact. Our process ranged from aligning our emission factors with reputable sources — like the Environmental Protection Agency (EPA), SmartWay and the GHG Protocol — to performing a regression analysis for 1,000 lanes.

To see the new formulas, download the full summary here.

The results are in: 

Updated STL emission formula

Updated formula for comparing LTL and STL emissions

  • We use inspiration from EPA SmartWay LTL Carbon Calculator Technical Documentation (Version 1.0) to inform how we calculate LTL emissions::
    • We estimate that LTL freight travels about 4% more linehaul miles than STL*.
    • We use 15.6 for the pickup and drop-off miles of one LTL load.
    • For our formula comparing LTL and STL emissions, we assume a load of 25,500 pounds  — the average weight of an LTL load, according to SmartWay research — for fuel economy.
    • We assume the average payload for LTL freight is a cubed-out weight.
  • We match the EPA’s 2021 guidance on the carbon emission factor. 
  • We use a variable to estimate the CO2e LTL terminals emit, which doesn’t apply to STL.
  • We estimate methane (CH4) and nitrous oxide (N2O) emissions.*
    • *We calculate CH4 and N2O emissions based on grams per mile of freight driven and the percentage of the truck that the freight takes up. We then convert the grams of emitted gasses into carbon dioxide equivalents  (CO2e). We also assume truck models of 2007 or later and use the EPA Emission Factors for Greenhouse Gas Inventories 

Using these conditions, we estimate that switching from LTL to STL can lower GHG emissions by about 15%*.

  • *We derived this average by comparing LTL and STL emissions on 1,000 Flock Freight lanes. 

New formula for comparing unoptimized TL and STL emissions

TL loads can combine into fewer STL loads; in other words, a single truck can run one STL load instead of two trucks running one unoptimized TL load each. 

Although an STL load carries more freight and gets fewer miles per gallon than a TL load, STL mileage distance is lower. The reduction in the number of trucks and miles makes STL emissions significantly lower than TL emissions.

Our formula for calculating STL emissions when switching from unoptimized TL includes several key variables: distance of the load, MPG of the truck based on weight of the load, an emission factor converting diesel to carbon dioxide (CO2), and measurements of CH4 and N2O. 

Using these conditions, we estimate switching from unoptimized TL to STL can lower emissions by about 40%.

Additionally, booking STL for smaller loads that might otherwise move with TL service can result in even higher emission reductions. 

Take action with us

We’re an industry-disrupting technology company that’s signed The Climate Pledge and committed to net-zero carbon emissions by 2040, but our purpose-driven commitment to the planet has already begun. To meet our promise of running FlockDirect loads 100% carbon neutral, we’re retroactively purchasing carbon offsets for 2021 in line with our updated emission calculations. We’re not cutting any corners when it comes to the promises we’ve made to our customers, employees, community and planet.

As we work on reducing emissions to make freight shipping more sustainable, we encourage all shippers to join us in our mission: reimagine and reinvent the freight industry by relentlessly eliminating waste and inefficiency.

Flock Freight customers can count on us to help them understand their environmental impact through regular sustainability reports.

Want to see the full list of emission calculations? Download our guide here.


Check out the sources we used to derive our new calculations:

Contact Flock Freight’s sustainability strategist, Katherine Stolin, with any questions regarding our emission calculations.

See Flock Freight’s updated emission formulas.