Speed Limiters and Emissions: Reducing Your Fleet’s Carbon Footprint

The transport sector is responsible for approximately 27% of the UK’s greenhouse gas emissions, making it the largest emitting sector. Within transport, heavy goods vehicles, vans, and buses account for a significant and growing share of emissions.

Fleet operators are under increasing pressure to reduce emissions — from government regulation, customer requirements, industry accreditation schemes, and public expectation. Speed limiters are one of the simplest and most cost-effective measures available to achieve measurable emissions reductions.

The Speed-Emissions Relationship

The relationship between vehicle speed and emissions is direct and well-quantified. Because emissions are proportional to fuel consumption, any reduction in fuel use translates to an equal reduction in CO2 and other exhaust emissions.

At higher speeds, the dominant factor is aerodynamic drag, which increases with the square of velocity. This means emissions rise disproportionately as speed increases above approximately 40 to 45mph for a typical commercial vehicle.

CO2 Emissions Reduction by Speed

Based on Department for Transport and Energy Saving Trust data:

Speed Reduction	CO2 Reduction
HGV: 65mph to 56mph	12-15%
HGV: 60mph to 56mph	5-8%
Van: 70mph to 60mph	10-12%
Van: 70mph to 65mph	5-7%
Coach: 70mph to 62mph	8-12%

These are the same percentages as fuel savings — because CO2 emissions are directly proportional to the volume of diesel (or petrol) combusted. Every litre of diesel burned produces approximately 2.68 kg of CO2. Every litre saved eliminates 2.68 kg of CO2.

Real-World Fleet Emissions Reduction

For a fleet of 100 HGVs, each covering 100,000 miles per year at an average fuel consumption of 8.5 mpg:

• Annual fuel consumption per vehicle: 11,765 gallons (53,478 litres)
• Annual CO2 per vehicle: 143,321 kg (143.3 tonnes)
• 10% reduction from speed limiting: 14,332 kg (14.3 tonnes) per vehicle
• Fleet-wide CO2 reduction: 1,433 tonnes per year

For a fleet of 200 delivery vans, each covering 25,000 miles per year at 32 mpg:

• Annual fuel consumption per vehicle: 781 gallons (3,551 litres)
• Annual CO2 per vehicle: 9,517 kg (9.5 tonnes)
• 10% reduction from speed limiting: 952 kg per vehicle
• Fleet-wide CO2 reduction: 190 tonnes per year

These are substantial, auditable reductions achieved through a single, relatively low-cost intervention.

Beyond CO2: Air Quality Pollutants

Speed limiters also reduce emissions of air quality pollutants — nitrogen oxides (NOx), particulate matter (PM), and hydrocarbons (HC). These pollutants have direct health impacts, particularly in urban areas, and are subject to increasingly stringent regulation.

NOx and PM emissions from diesel engines are complex and depend on engine load, temperature, and exhaust aftertreatment system effectiveness. However, the general principle holds: lower speeds mean lower engine loads for a greater proportion of the journey, which generally means lower emissions of these pollutants.

For fleets operating in Clean Air Zones (CAZs) — which are being implemented in cities across the UK including Birmingham, Bradford, Bristol, and the Greater Manchester area — reducing emissions through speed management complements vehicle replacement strategies and demonstrates a comprehensive approach to air quality improvement.

Emissions Reporting and Net-Zero Commitments

An increasing number of fleet operators are making net-zero commitments or are required to report emissions as part of corporate sustainability frameworks. Speed limiters provide emissions reductions that are simple to quantify, verify, and report.

Scope 1 Emissions

Fleet fuel consumption falls under Scope 1 (direct) emissions in the Greenhouse Gas Protocol framework. Speed limiter-driven fuel reductions directly reduce Scope 1 emissions.

FORS Reporting

The Fleet Operator Recognition Scheme (FORS) requires operators to monitor and report fuel consumption and CO2 emissions. FORS Bronze requires fuel monitoring; FORS Silver and Gold require evidence of active measures to reduce fuel consumption and emissions. Speed limiters are one of the most straightforward measures to demonstrate.

Customer Requirements

Major retailers, food manufacturers, and public sector organisations are increasingly requiring their logistics suppliers to report emissions and demonstrate reduction measures. The ability to show documented speed limiter installations, with quantified emissions reductions, strengthens tender responses and supplier assessments.

SECR Reporting

UK companies meeting the qualifying criteria for Streamlined Energy and Carbon Reporting (SECR) must include transport energy in their annual reports. Speed limiter-driven reductions contribute to the narrative of energy efficiency measures that SECR reporting requires.

Speed Limiters as Part of a Fleet Decarbonisation Strategy

Speed limiters should be viewed as one element of a broader fleet emissions reduction strategy. They complement other measures including driver training (eco-driving techniques), route optimisation, vehicle specification (aerodynamic devices, low rolling resistance tyres), alternative fuels and electric vehicles, and idle reduction.

What makes speed limiters particularly attractive is their immediacy and certainty. Unlike driver training (which requires ongoing reinforcement), route optimisation (which requires software investment and process change), or vehicle replacement (which requires capital investment over a multi-year fleet cycle), speed limiters deliver emissions reductions from the day they are installed, with no ongoing behavioural or process requirements.

For fleet operators who are early in their decarbonisation journey, speed limiters provide quick, measurable wins that demonstrate commitment while longer-term strategies (such as fleet electrification) are developed.

TrackSpeed: Emissions Data and Reporting

AutoKontrol’s TrackSpeed system, which combines speed limiting with ScorpionTrack Fleet GPS tracking, provides additional emissions management capabilities. The tracking platform records actual fuel consumption data per vehicle and per journey, idling time (a significant contributor to unnecessary emissions), driver behaviour events (harsh acceleration, which wastes fuel and increases emissions), and journey efficiency metrics.

This data feeds directly into emissions reporting, helping fleet operators track their progress against net-zero targets and identify opportunities for further improvement beyond speed limiting alone.

Getting Started

Speed limiters are one of the fastest, lowest-cost paths to measurable fleet emissions reduction. The emissions savings mirror the fuel savings — so the environmental benefit comes with a direct financial return.

Request a free quote for speed limiters for your fleet. We can calculate the specific CO2 and fuel savings your fleet will achieve based on your vehicle types, mileage profiles, and current operating speeds.