How do I calculate emissions from trucks idling?
Multiply idling litres per hour by 2.68 kg CO2 per litre of diesel. Take the idle fuel rate from telematics or the engine data, not a guess, then multiply by idle hours from the tracker. Idling is already inside your fuel invoices, so report it as a sub-figure.
Getting the idle rate
- Telematics or engine data that logs fuel while stationary.
- A test: run the engine at idle for an hour and measure the tank drop.
- Use an assumed rate only if labelled as one.
Do not double count
Idle fuel is part of the litres you already buy. Use the idling figure to target savings, not to add to the total.
Cutting it
Engine-off rules at loading bays, auto shut-off and cab heaters or coolers that do not need the engine all reduce idle hours.
Worked example: 20-truck fleet (one month, illustrative inputs)
- Idling at an assumed 2 litres per hour: 2 x 2.68 = 5.36 kg CO2 per hour
- Fleet idling: 20 trucks x 2 hours a day x 25 days = 1,000 hours
- Monthly idling: 1,000 x 5.36 = 5,360 kg CO2
The 2 litres per hour idle rate is an assumed input; replace it with your telematics figure.
What Senseible does here
Senseible reads fuel invoices and fuel card statements (diesel 2.68 and CNG 2.69 kg CO2, IPCC 2006 defaults) into a fingerprinted Scope 1 record. Hired transport goes to the Scope 3 evidence trail, and distance or tonne-km estimates are labelled as estimates.
Sources: GHG Protocol Corporate Standard, IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults), GLEC Framework for logistics emissions (Smart Freight Centre)
Last reviewed 2026-10-21.