Company car fleets are increasingly under scrutiny for fuel costs, CO₂ emissions and driver safety. Many company car drivers regularly exceed 70 mph on motorway routes, yet the fuel penalty above that speed is dramatic. Fitting a speed limiter set to 70 mph can cut fuel consumption by up to 28% compared to unrestricted driving above 80 mph — use the calculator below to see what your fleet could save.
How We Calculate Your Savings
The baseline for our calculation is typical company car fuel consumption at unrestricted motorway speeds — often 80 mph or above for unsupervised drivers. At these speeds, aerodynamic drag is the dominant force and fuel consumption rises steeply. Our model uses the relationship between speed and aerodynamic resistance to estimate consumption per mile.
Restricting company cars from 80+ mph to 70 mph delivers a fuel saving of approximately 28%, which is substantially higher than the equivalent saving for HGVs or vans. This is because cars have a higher top speed baseline, a steeper aerodynamic drag curve at high speed, and the proportional speed reduction is greater. We apply this saving across your fleet’s annual motorway mileage, multiply by fuel price, and also calculate CO₂ savings using 2.31 kg CO₂ per litre for petrol or 2.68 kg for diesel.
Why Fit a Speed Limiter?
The financial case for company car speed limiters is compelling. A single company car driver consistently travelling at 85 mph rather than 70 mph may be wasting £1,500–£2,500 in fuel per year beyond what is necessary. Across a fleet of 50 vehicles, that represents a potential saving of £75,000–£125,000 annually — far exceeding the cost of fitting and maintaining speed limiters.
From a corporate governance perspective, directors and fleet managers have a duty of care to ensure company vehicles are operated safely and legally. The UK national speed limit of 70 mph applies to motorways, and any company car driver exceeding it is both breaking the law and exposing their employer to potential liability. A speed limiter set to 70 mph removes this risk entirely.
The EU’s ISA (Intelligent Speed Assistance) mandate requires all new passenger cars sold in the EU from 2024 to include speed assistance technology. For UK fleets operating EU-registered vehicles or sourcing vehicles from EU manufacturers, awareness of this technology is increasingly relevant. Retro-fit speed limiters offer a cost-effective solution for existing fleets.
Insurers are increasingly pricing fleet risk based on evidenced speed management. Company car fleets with verified speed limiters or telematics showing speed compliance consistently attract lower premiums and better terms. Combined with a GPS tracking solution such as AutoKontrol TrackSpeed, operators gain both the speed management and the evidential data needed for insurance and compliance purposes.
Frequently Asked Questions
Are speed limiters required on company cars?
There is currently no UK legal requirement to fit speed limiters to company cars under 3.5 tonnes. However, all new cars sold in the EU from 2024 must include ISA technology, and fleet operators have a duty of care to ensure vehicles are operated within speed limits. Speed limiters are a practical way to enforce this.
How much fuel does a company car waste driving above 70 mph?
Fuel consumption increases significantly above 70 mph due to aerodynamic drag. Compared to driving at 70 mph, travelling at 85 mph uses approximately 25–30% more fuel per mile. For a company car covering 20,000 motorway miles per year, this can represent over £1,500 in wasted fuel annually.
Can a speed limiter reduce company car insurance costs?
Yes. Many commercial fleet insurers offer reduced premiums for vehicles with certified speed limiters, recognising the lower risk profile of speed-managed fleets. The saving varies by insurer and fleet profile, but is typically 5–15% on the relevant portion of the premium. Ask your broker to seek terms with and without speed management technology.
How does ISA (Intelligent Speed Assistance) differ from a fitted speed limiter?
ISA systems use GPS map data and sign recognition to advise or temporarily limit speed based on the posted limit — but they can typically be overridden by the driver. A fitted speed limiter is a calibrated, tamper-evident mechanical system that cannot be overridden in normal operation. For fleet policy enforcement, a fitted limiter provides much stronger compliance assurance than ISA alone.
Will a speed limiter affect resale value?
For company cars, a speed limiter set to 70 mph (the UK national speed limit) has negligible impact on resale value for most buyers. Commercial buyers and fleet operators may view it positively as evidence of responsible operation. The device can be removed or recalibrated if required, and this is factored into the cost of installation.