Speed Limiter FAQ: Your Questions Answered

A speed limiter is a device fitted to a vehicle that prevents it from exceeding a pre-set maximum speed. It works by electronically or mechanically controlling the fuel supply or throttle signal to the engine — once the vehicle reaches the set limit, the device gradually reduces engine power so the vehicle cannot travel faster. Speed limiters are legally required for HGVs and buses in the UK and EU. AutoKontrol has been manufacturing speed limiters for over 41 years and is one of the world's leading specialists in this technology.

A speed limiter monitors vehicle speed via the vehicle speed sensor (VSS) or CAN bus, and automatically reduces the throttle when the set speed is reached. In modern Drive-By-Wire (DBW) systems like AutoKontrol's, the limiter intercepts the electronic throttle signal between the accelerator pedal and the engine management system. When the vehicle reaches the limit, it gradually reduces the throttle signal, causing a smooth, gradual deceleration — the driver feels natural slowing rather than an abrupt cut-off.

Yes — speed limiters are mandatory in the UK for goods vehicles over 3.5 tonnes gross weight (set at 56mph / 90km/h) and buses with more than 8 passenger seats (set at 62mph / 100km/h). Light commercial vehicles and cars do not currently require mandatory speed limiters in the UK. However, new EU Intelligent Speed Assistance (ISA) regulations, which apply to vehicles sold in the EU from July 2024, may influence future UK policy.

A speed limiter sets a maximum speed that the vehicle cannot exceed — the driver cannot override it. Cruise control maintains a set speed without the driver pressing the accelerator, but can be overridden at any time by pressing the pedal harder. In short: a speed limiter is a safety and legal compliance device that enforces a hard limit, while cruise control is a driver comfort feature with no enforcement capability.

No — a correctly installed speed limiter cannot be overridden by the driver. AutoKontrol speed limiters use tamper-resistant sealing that makes any attempt to bypass, disconnect, or modify the device detectable during DVSA inspections. Tampering with a legally required speed limiter is a criminal offence in the UK, carrying fines, operator licence penalty points, or prosecution by the Traffic Commissioner.

Yes — speed limiters typically save 10-15% on fuel costs. Reducing maximum speed by just 10mph significantly reduces fuel consumption because aerodynamic drag increases exponentially with speed. For a fleet of 50 HGVs, this can mean tens of thousands of pounds saved annually. Speed limiters also reduce tyre and brake wear, adding further cost savings. Most fleet operators find the device pays for itself within 6-12 months from fuel savings alone.

Speed limiters improve safety — speed is a factor in 24% of fatal road accidents in the UK. The common concern is that limiters prevent drivers from accelerating out of danger, but in practice, commercial vehicles rarely need sudden acceleration to avoid hazards. Braking, steering, and hazard awareness are far more effective responses. Studies consistently show that speed-limited fleets have fewer accidents, less severe injuries, and lower insurance claims than unrestricted fleets.

System 80 is AutoKontrol's flagship electronic speed limiter, using Drive-By-Wire (DBW) throttle signal interception to control vehicle speed with precision to +/- 1km/h. EU/ECE R89 approved, supporting 12V and 24V systems, and compatible with virtually all commercial vehicles fitted with electronic throttle systems — including HGVs, LCVs, buses, and specialist vehicles. System 80 is one of the most widely deployed speed limiter devices in the commercial vehicle sector globally.

TrackSpeed is the only device on the market combining a speed limiter with GPS tracking. It integrates AutoKontrol's speed limiter with ScorpionTrack Fleet GNSS tracking in a single unit — one device, one installation, one subscription. TrackSpeed gives fleet operators speed limiting compliance and full real-time fleet visibility from a single system. Features include zone-based speed control via GeoKontrol, driver behaviour analytics, route optimisation, and a complete fleet management platform with iOS and Android apps.

GeoKontrol is a GPS-based speed limiting system that automatically adjusts the vehicle's maximum speed based on its GPS location. Fleet managers define custom speed zones (for example, 5mph in the depot, 20mph near schools, 30mph in residential areas) and GeoKontrol enforces these automatically when the vehicle enters each zone — without any driver intervention. GeoKontrol is available as part of TrackSpeed.

AutoKontrol speed limiters are compatible with virtually all commercial vehicles fitted with electronic throttle systems. Supported HGV brands include DAF, MAN, Mercedes, Scania, Volvo, Iveco, and Renault. Supported LCVs include Ford Transit, Mercedes Sprinter, Volkswagen Crafter, Iveco Daily, and Renault Master. Supported buses include Alexander Dennis, Optare, Wrightbus, and Volvo. We also support specialist vehicles and plant — contact our technical team if you are unsure about your vehicle.

Yes — although speed limiters are not legally required for LCVs under 3.5 tonnes, many fleet operators choose to fit them voluntarily. Benefits include 10-15% fuel savings, 5-15% reduction in insurance premiums, improved driver safety, and reduced accident liability. AutoKontrol supplies and installs speed limiters for all major LCV models including Ford Transit, Mercedes Sprinter, Volkswagen Crafter, Iveco Daily, and Renault Master. Contact us for a free fleet LCV quote.

SENT (Single Edge Nibble Transmission) is a digital throttle signal protocol used in the latest generation of Euro VI+ commercial vehicles. A SENT speed limiter is specifically designed to work with these new digital throttle signals. AutoKontrol manufactures SENT-compatible speed limiters for the latest HGVs and LCVs that have moved beyond traditional analogue throttle systems.

Speed limiter installation takes 2-3 hours per vehicle. For TrackSpeed (the combined speed limiter + GPS tracking system), allow 3-4 hours. Our approved installers come to your premises to minimise vehicle downtime, and for large fleet deployments we schedule installations around your operational requirements.

Yes — AutoKontrol provides nationwide UK installation through our survey and installation service, operated by SGH Connect (part of Scorpion Group Holdings). Our engineers travel to your premises anywhere in the UK, whether that is a single depot or multiple sites across the country.

Speed limiter costs vary by product, vehicle type, and fleet size, with volume discounts available for larger fleets. Most fleet operators find speed limiters pay for themselves within 6-12 months through 10-15% fuel savings and 5-15% insurance premium reductions. Contact us for a free, no-obligation quote tailored to your requirements — pricing includes the device, installation, and compliance documentation.

Yes — every AutoKontrol installation includes complete DVSA-ready documentation: EU/ECE R89 type approval certificate, installation certificate, and calibration record. This documentation is required for DVSA roadworthiness inspections and operator licence compliance. We maintain records of all installations so replacement certificates can be issued if needed.

Speed limiters should be inspected and recalibrated at least every two years, or whenever the vehicle's tyres, axle ratio, or gearbox is changed (as this affects the speed signal). DVSA can check calibration during roadside inspections. AutoKontrol provides calibration services through the SGH Connect national installer network, and each calibration includes updated documentation for your compliance records.

All AutoKontrol speed limiters carry a two-year manufacturer's warranty from the date of installation, covering defects in materials and workmanship under normal operating conditions. The warranty does not cover damage resulting from unauthorised modification or tampering, incorrect installation by non-approved installers, water damage exceeding the product's IP rating, or normal wear and tear. Installation must be carried out by an AutoKontrol approved installer for the warranty to be valid.

All goods vehicles over 3.5 tonnes gross weight must be fitted with a speed limiter set at 56mph (90km/h) under UK law. This is required under the Road Vehicles (Construction and Use) Regulations 1986 (as amended). The speed limiter must be EU/ECE R89 approved and maintained in good working order. DVSA checks compliance during roadside inspections — non-compliance can result in prohibition notices, fines, and Traffic Commissioner action against the operator licence.

Your vehicle will receive a prohibition notice and cannot be used until the speed limiter is repaired or replaced. Additionally, the operator may face a fixed penalty notice, referral to the Traffic Commissioner (which can affect the O-licence), and in serious cases, criminal prosecution. Repeated violations or evidence of tampering carry the most severe penalties. Installing and properly maintaining an approved AutoKontrol speed limiter ensures you pass every inspection.

No — speed limiters are not currently a legal requirement for LCVs (light commercial vehicles under 3.5 tonnes gross weight) in the UK. However, many fleet operators fit them voluntarily as they reduce fuel costs by 10-15%, lower insurance premiums by 5-15%, and improve driver safety. EU ISA regulations (mandatory on new vehicles sold in the EU from July 2024) may influence future UK policy on LCV speed limiters.

ISA (Intelligent Speed Assistance) is a system that uses GPS and cameras to detect the current speed limit and warn the driver — or actually limit the vehicle's speed — if they exceed it. ISA became mandatory on all new vehicles sold in the EU from July 2024. The UK has not yet mandated ISA, but it is expected to influence future regulations. AutoKontrol's GeoKontrol technology offers similar GPS zone speed management designed specifically for commercial fleets.

HGVs over 3.5 tonnes are limited to 56mph (90km/h) by the speed limiter device. On UK roads, the actual speed limits for HGVs are: 30mph in built-up areas, 50mph on single carriageways (vehicles over 7.5t), 60mph on dual carriageways, and 60mph on motorways. The 56mph speed limiter means most HGVs cannot in practice reach the 60mph motorway limit. These limits are enforced by the speed limiter device and by law.

Buses with more than 8 passenger seats must be fitted with a speed limiter set at 62mph (100km/h). On UK roads, bus speed limits are: 30mph in built-up areas, 50mph on single carriageways, 60mph on dual carriageways, and 60mph on motorways. The 62mph limiter ensures buses cannot significantly exceed these limits even on motorways.

Operating an HGV over 3.5 tonnes without a correctly functioning speed limiter can result in: an immediate prohibition notice (vehicle stopped from operating), a fixed penalty fine of up to £300, referral to the Traffic Commissioner — who can curtail, suspend, or revoke the operator licence. In cases of repeated violations or deliberate tampering, criminal prosecution is possible. Penalties apply to both the driver and the operator.