For most UK shippers, the largest share of their carbon footprint sits outside their own operations. The warehouse lighting, the company cars and the site energy bill are all measurable and all comparatively small. The freight moving in and out of the building is neither.
That freight sits in Scope 3, and it is where sustainability in logistics either gets taken seriously or gets estimated once a year and filed. This article covers what Scope 3 actually asks of a shipper, why transport emissions are harder to report than the rest, and the changes that move the number rather than just the reporting of it.
Where freight sits in the emissions picture
The Greenhouse Gas Protocol splits emissions into three scopes:
- Scope 1: direct emissions from sources you own or control, including your own fleet
- Scope 2: indirect emissions from the energy you buy
- Scope 3: everything else in your value chain, upstream and downstream
Freight moved by a third-party carrier is Scope 3. Specifically it falls into Category 4, upstream transportation and distribution, for inbound and outbound movements you pay for, and Category 9, downstream transportation and distribution, for movements you do not pay for but that carry your product.
The practical consequence is that the emissions belong to you while the data sits with somebody else. You are reporting on vehicles you do not own, driven by people you do not employ, on routes you may not have specified.
Why the reporting side is the hard part
Most shippers start with a spend-based estimate: multiply what you spent on transport by an emissions factor for the sector. It is quick, it satisfies a first year of reporting, and it is close to useless for reduction work, because the number moves with your freight spend rather than with your actual carbon.
Cut your rates by ten per cent and a spend-based model shows a ten per cent emissions reduction while the same lorries run the same miles.
Activity-based reporting is the alternative. It calculates from what actually happened: vehicle type, fuel, distance, weight carried, and how full the vehicle was. This is what the GLEC Framework standardises, and it is now aligned with ISO 14083, the international standard for quantifying transport chain emissions. A carrier reporting on a GLEC-accredited basis is producing figures that will stand up to audit and that respond to operational change.
If you report under SECR, or you supply customers who report under CSRD, this distinction determines whether your transport data is usable or simply present.
Where the emissions actually come from
Four things drive road freight emissions, and only one of them is the vehicle.
1. Empty running. In the 12 months to March 2026, GB-registered HGVs travelled 5,714 million kilometres empty, which is 30% of all vehicle distance covered (DfT, Domestic road freight statistics, August 2026). Nearly a third of UK lorry mileage carries fuel burn and no payload, largely because freight flows are unbalanced: more goes into some regions than comes back out.
2. Poor vehicle fill. A half-empty trailer emits almost as much as a full one. Emissions per tonne-kilometre, the metric that matters, roughly double when fill halves.
3. Route and mode. Indirect routing, unnecessary trunking through a depot, and moving by road where rail or short sea would serve.
4. Vehicle and fuel. Euro VI diesel against older stock, HVO, electric for urban and regional work.
Most shippers reach for the fourth item first because it is the most visible. It is also the one they have least control over, since it depends on the carrier’s fleet investment cycle. The first two are where a shipper’s own decisions make the difference.
Practical reductions, in order of what a shipper controls
Improve vehicle fill before anything else
Fill is the cheapest carbon reduction available, because it also cuts cost. Consolidating two part loads into one full load removes a vehicle from the road entirely.
- Review whether orders to the same region can be held and shipped together
- Check pallet configuration. Freight that cannot be double-stacked wastes half the cubic capacity of the trailer
- Look at your split between full loads and part loads across the year rather than order by order
Cut empty running through the carrier network
Empty miles are solved by matching return loads, which needs a network big enough to find them. This is a carrier selection question rather than an internal one.
Ask providers directly: what proportion of your mileage runs empty, and how do you backfill returns? A carrier using digital load matching across a large network will answer with a number. One relying on manual planning across a small fleet often cannot.
Relax the constraints that force inefficiency
Some emissions are created by the brief rather than the transport. Same-day and timed deliveries reduce the carrier’s ability to consolidate or backfill, so each one carries a carbon cost as well as a rate premium.
- Identify which deliveries genuinely need a fixed time and which inherited one
- Widen delivery windows where the receiving site allows it
- Book in against slots properly, since a missed slot means a wasted return journey
Review network shape
Where freight is distributed from determines how far it travels. Regional hubs cut final-mile distance but add trunking; central warehousing does the reverse. Neither is universally lower carbon, so it needs modelling against your actual demand distribution rather than assumed.
Then look at fuel and vehicle
Once fill and empty running are addressed, ask carriers about HVO availability on your lanes, electric capability for urban work, and fleet Euro standard. These deliver real reductions but they work on the carbon per mile, and it is more effective to remove the mile.
What to ask your carrier for
If you are formalising transport emissions reporting, four things make it workable:
- Activity-based data, not spend-based. Distance, weight, vehicle type and fuel per consignment
- A stated methodology. GLEC Framework or ISO 14083, with the emissions factors named
- Reporting at consignment level. Annual totals cannot tell you which lanes to fix
- Empty running and fill rate figures. These are the operational levers, so you need visibility of them
If a provider can only supply an annual estimate, you can report it, but you cannot manage it.
Starting point
Sustainable logistics work tends to stall when it begins with the target rather than the baseline. The order that works is: get activity-based data for a full quarter, find which lanes carry the highest emissions per tonne-kilometre, and address fill and routing on those before committing to anything fleet-related.
FLS built its Emissions Manager product for exactly this. Released in June 2024 with support from the Welsh Government, it provides GLEC-accredited emissions data for every load FLS carries, from single load notifications through to a carbon dashboard with detailed analytics. Combined with return load matching across a carrier network of over 55,000 vehicles, which is what keeps empty running down on the lanes we operate, it gives shippers the activity-based data the reporting actually requires. If you are building a Scope 3 baseline for your inbound and outbound transport, our UK road freight services team can supply consignment-level data for your existing volumes.
