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Fuel accounts for a third of transport businesses’ core running costs, according to Logistics UK. So when a vehicle idles, burning fuel without moving, it creates zero return on that investment. But idling isn’t just a waste of fuel; it costs in other ways too.
The impact of engine idling can be:
- Financial: Added to the cost of wasted fuel are higher vehicle maintenance costs
- Physical: Increased engine wear and shorter vehicle lifespan
- Environmental: Higher carbon emissions
- Legal: Contrary to the Highway Code and against FORS guidance
Engine Idling: The Ghost in the Machine
In fact, an idling engine has two ghosts: “ghost mileage” and “ghost wear”. Ghost miles are miles missed because fuel has been burned to tick over the engine instead of using it to move.
These “Phantom miles” also take a double toll on the vehicle. Diesel engines are designed to move, so when they don’t, they wear more quickly. 1 minute of engine idling equals 2 miles of engine wear.
This is because idling only partially combusts diesel fuel, leaving heavy carbon deposits on critical internal components. This causes twice as much wear to parts like Exhaust Gas Recirculation (EGR) valves and Diesel Particulate Filters (DPFs), resulting in “ghost wear” that causes premature clogging and higher maintenance and servicing costs.
A typical heavy-duty lorry or HGV burns roughly 2 litres of diesel per hour while idling. Whilst commercial trucks spend an average of 53 minutes per day idling, or 14.6% of their total engine running time, clocking up those ghosts.
The fuel cost of empty miles is obvious, but the accelerated wear caused by excessive idling can reduce a truck engine’s usable life by up to 50%. This means higher maintenance bills and a shorter service life for the fleet.
Engine Idling: The Environmental and Legal Impact
But the cost of an idle engine is not just measured in the profit margins. There are also environmental and legislative implications.
Heavy diesel trucks can release up to 10 times more Nitrogen Oxides (NOx) and particulate matter when idling compared to modern passenger cars. According to FORS, a litre of diesel fuel wasted by an idling engine releases 2.64 kg of CO2 into the atmosphere.
In an era of carbon emissions and low-carbon zones across the UK and European cities, idling is a big problem. Logistics companies are facing increasing pressure from corporate clients and regulators to do more to lower their carbon footprint.
Companies must also adhere to highway regulations. Under the UK Highway Code, leaving a vehicle engine running unnecessarily while stationary on a public road is illegal and subject to local council fines, particularly within low-emission zones like London.
How to Reduce Engine Idling: The 5 Ws Method
So, what’s the best way to tackle the idling gas guzzler that’s killing your margin? The first step to tackling the problem is to understand it. Companies now have access to a huge range of detailed data thanks to synchronised technology, tracking and engine management systems.
Having visibility on key metrics such as engine temperature and driver behaviour can help firms make targeted improvements. One way to do this is to drill down into the who, what, when, where and why of engine idling.
Who: The first W, or “who”, is the people, especially drivers. Driver behaviour can have a huge impact on minimising idling. Telematics data can be analysed, and training can be tailored to individual drivers. This proactive approach encourages best practice across your team.
What: What vehicle is it, and what can be done to reduce idling? It can make sense to install auxiliary power units (APUs) or fuel-fired cab heaters that bypass the need to use the engine. Modern vehicles may have automatic engine start-stop and optimised idling technology. Alternative fuels, such as hydrogen-powered or electric trucks, could also be an option.
When: The “when” of deliveries can also impact idling. Scheduling deliveries to avoid congested areas at peak times can help minimise idling costs.
Where: Synching GPS with engine management systems can help to identify high-idling routes and locations. It may then be possible to reroute or check any location-specific reasons for a spike in engine idling.
Why: Why is the idling happening? Modern fleet management systems (telematics) can identify different types of idling. Operational idling, such as waiting at traffic lights, versus discretionary idling, such as a driver keeping the cabin warm while parked. This matters because some idling is necessary, whereas some isn’t. Knowing the reason for idling helps firms focus their efforts effectively.
SMART Driving: How Invo Fulfilment Reduced Idling by 37%
Engine idling was something that we were keen to address. We already had the technology in place to give us the visibility we needed, and a coaching programme that has been rolled out to all Involvement colleagues.
Our eco-driving scoreboard gives us a month-on-month view of patterns of driving, with many of our drivers receiving the highest-rated eco-scores month after month. Because it’s possible to measure and analyse idling, we can be SMART (specific, measurable, achievable, relevant and timed) about our idling targets.
The eco-driving focus has made a real impact on operations. As our Director of Operations, Oliver Lancaster explains,
“These ratings make a real difference. For example, we have reduced engine idling by 37% year on year, saving fuel and harmful emissions at the same time.”
Given the financial and environmental costs of idling, that’s good news all round; and if you’re looking to work with a transport company that’s anything but idle, please get in touch.
- The Hidden Costs of Engine Idling - September 2, 2026
- Involved Magazine | Volume 2 - July 31, 2026
- Invo Fulfilment sponsors Southam in Bloom - July 29, 2026