Types of Speed Limiters: Mechanical vs Electronic vs GPS

There are five main types of speed limiters: mechanical (cable) limiters, electronic Drive-By-Wire (DBW) limiters, SENT electronic limiters, GPS geofenced limiters and combined speed limiter and tracking systems. They differ in how they control the throttle and whether the maximum speed is fixed or changes by location. AutoKontrol makes a speed limiter of each type.

A system that automatically sets the speed of a motor vehicle is called cruise control when it holds a speed the driver has chosen, or a speed limiter (also known as a speed governor or speed restrictor) when it caps the vehicle’s maximum speed. Cruise control is a convenience feature the driver can cancel at any time, whereas a fitted speed limiter enforces a ceiling for safety and compliance. If you are new to the technology, start with our guide to what is a speed limiter.

Speed Limiter Types Compared

Type	How it controls speed	Speed setting	Driver can override?	Best for
Mechanical speed limiter	Restricts throttle cable travel	Fixed at installation	No (sealed)	Older cable-throttle vehicles, harsh environments
Electronic (DBW)	Modifies the electronic accelerator pedal signal	Fixed at installation	No (sealed)	HGVs, buses and vans with electronic throttle
Electronic (SENT)	Modifies the digital SENT throttle sensor signal	Fixed at installation	No (sealed)	Latest-generation trucks and vans
GPS geofenced	Changes the maximum speed by location	Varies by zone	No, within a zone	Depots, sites, schools, 20mph zones
Combined limiter and tracking	Speed limiter plus GNSS fleet tracking	Fixed, with optional zones	No (sealed)	Fleets needing compliance and visibility
ISA (new cars, for comparison)	Warns or briefly reduces power above the road limit	Follows road limits	Yes	Driver assistance
Cruise control (for comparison)	Holds a speed chosen by the driver	Driver chosen	Yes	Driver convenience

1. Mechanical Speed Limiters

A mechanical speed limiter is the original form of speed control. It uses a precision linkage fitted inline with the throttle cable (or, on older diesels, acting on the fuel injection pump) to limit how far the throttle can open, so the vehicle cannot accelerate beyond the set speed.

AutoKontrol’s System 80 is a mechanical speed limiter that works on the vehicle’s fuel line, designed for older vehicles with mechanically controlled engines:

• No electronic dependency: no software, firmware or power supply required
• Accuracy: +/- 1-2 km/h at the set speed
• Tamper protection: tamper-evident seal with a unique serial number
• Installation: typically around 60 minutes, with no ECU programming
• Approval: EU/ECE R89 type-approved

Best for: older commercial vehicles with cable throttles, plant and agricultural vehicles, and fleets operating in dusty, wet or remote environments. For a side-by-side view, read electronic vs mechanical speed limiters.

2. Electronic (Drive-By-Wire) Speed Limiters

Electronic Drive-By-Wire speed limiters are the standard for most modern commercial vehicles. In a drive-by-wire vehicle there is no throttle cable: the accelerator pedal sends an electronic signal to the engine management system. A DBW speed limiter sits between the two, reads road speed from the vehicle speed sensor or CAN bus, and progressively reduces the throttle signal as the set speed is reached.

• Accuracy: +/- 1 km/h
• Power supply: 12V and 24V (auto-sensing)
• Speed range: adjustable from 10 to 130 km/h
• Tamper resistance: sealed, tamper-resistant enclosure
• Approval: EU/ECE R89 type-approved

Best for: HGVs, buses, coaches and vans with electronic throttles, for both mandatory compliance and voluntary speed management. See the DBW speed limiter for specifications.

3. SENT Electronic Speed Limiters

Many of the latest trucks and vans use throttle position sensors that communicate using SENT (Single Edge Nibble Transmission), a digital protocol. A conventional DBW limiter expects an analogue or PWM signal and will not work on these vehicles, so a SENT speed limiter is needed. It processes the SENT signal natively and limits speed with the same precision as a DBW unit.

Best for: newer Euro VI (and later) commercial vehicles fitted with SENT throttle sensors. If you are unsure which throttle type your vehicles use, a compatibility check will confirm it.

4. Fixed Top Speed vs Engine RPM Limiting

Most speed limiters apply top speed control: a single maximum road speed for the vehicle. This is the configuration used for regulatory compliance:

• HGVs over 3.5 tonnes (UK): 56mph (90 km/h), a legal requirement
• Buses and coaches (UK): 62mph (100 km/h), a legal requirement
• Voluntary van fleets: a lower setting chosen by the operator
• Site vehicles: low settings for on-site safety

Engine RPM limiting is different. It caps how fast the engine can rev rather than how fast the vehicle can travel, which helps prevent over-revving, can reduce fuel use during aggressive driving and lowers noise. RPM limiting is often used alongside road speed limiting rather than instead of it.

5. GPS Speed Limiters (Geofenced Speed Control)

A GPS speed limiter changes the vehicle’s maximum speed according to where it is. AutoKontrol’s GeoKontrol 2 is a standalone device combining a GNSS receiver, a speed limiter interface and 4G connectivity. When the vehicle enters a geofenced zone, its maximum speed drops to that zone’s limit; when it leaves, the default limit returns.

• Unlimited zones, drawn as polygons or circles in a web portal
• Schedules, so a school zone can apply only during set hours
• Over-the-air updates to every vehicle, with no workshop visit
• No driver input, and no way to override the zone limit

Use cases: 5mph depot limits, 20mph residential and school zones, construction sites and customer premises.

A GPS speed limiter is not the same as ISA. ISA on new cars advises the driver about the road limit and can be overridden; a geofenced limiter enforces limits the fleet operator has set.

6. Combined Speed Limiter and GPS Tracking (TrackSpeed)

TrackSpeed combines AutoKontrol speed limiter technology with ScorpionTrack Fleet GNSS tracking in a single device, available exclusively from AutoKontrol. It includes Drive-By-Wire speed control, GeoKontrol zone-based limits, real-time location, driver behaviour scoring, journey history and reporting through a web portal and iOS and Android apps.

Most fleets that need a speed limiter also need tracking. Buying them separately usually means two devices, two installations and two contracts. TrackSpeed replaces that with one device, one installation (typically around 60 minutes) and one dashboard.

What Is Speed Control in a Car?

Speed control in a car usually means one of three built-in systems:

• Cruise control holds a speed the driver has chosen until they brake or cancel it.
• Adjustable speed limiter lets the driver set a maximum speed, which can usually be exceeded with firm pressure on the accelerator.
• Intelligent Speed Assistance (ISA) reads the road speed limit and warns the driver, and can be overridden.

All three are driver-controlled. A fitted, sealed speed limiter is different because the driver cannot change or override it, which is why fleets use them. Our speed limiter vs cruise control guide explains the differences, and our car speed limiter guide covers options for cars.

Aftermarket and Branded Speed Limiters

Many people research aftermarket brands (for example, US names such as Zemco) when comparing speed limiter types. Whatever the brand, the questions are the same: does it suit the vehicle’s throttle type, is it tamper-evident, and for UK commercial vehicles, is it EU/ECE R89 type-approved? Our aftermarket speed limiter buyer’s guide sets out the criteria that matter when comparing suppliers.

Which Type of Speed Limiter Is Right for Your Fleet?

Need	Recommended solution
HGV or PSV compliance, electronic throttle	DBW speed limiter
Latest-generation vehicles with SENT throttle sensors	SENT speed limiter
Cable-throttle or harsh-environment vehicles	System 80 mechanical speed limiter
Van fleet speed management	DBW or SENT speed limiter, depending on throttle type
Zone-based speed control (depots, sites, schools)	GeoKontrol 2
Speed limiting plus fleet tracking	TrackSpeed

Not sure which is right for you? Contact our technical team for a free compatibility check, or request a quote and we will recommend the best solution for your fleet.

Frequently Asked Questions

What is a system that automatically sets the speed of a motor vehicle called?

A system that automatically holds a motor vehicle at a speed chosen by the driver is called cruise control. A system that automatically caps a vehicle’s maximum speed is called a speed limiter, also known as a speed governor or speed restrictor. Cruise control is for convenience and can be cancelled by the driver, while a fitted speed limiter enforces a maximum speed.

What is the difference between a mechanical and an electronic speed limiter?

A mechanical speed limiter physically restricts throttle cable travel, so it suits older vehicles with cable throttles and needs no power or software. An electronic speed limiter modifies the electronic throttle signal, so it suits modern drive-by-wire vehicles. The right choice is determined mainly by the vehicle’s throttle type.

What is speed control in a car?

Speed control in a car usually refers to cruise control, which holds a set speed, or an adjustable speed limiter, which lets the driver set a maximum speed. Many new cars also have Intelligent Speed Assistance, which warns the driver about the road speed limit. All of these can be adjusted or overridden by the driver, unlike a sealed fitted speed limiter.

Is a GPS speed limiter the same as ISA?

No. ISA on new cars uses map data and sign recognition to advise the driver of the road limit, and the driver can override it. A GPS speed limiter such as GeoKontrol 2 enforces maximum speeds in zones set by the fleet operator, and the driver cannot override the zone limit.

Which type of speed limiter do HGVs need?

UK goods vehicles over 3.5 tonnes need a type-approved speed limiter set to 56mph (90 km/h). The type depends on the vehicle: a DBW speed limiter for electronic throttles, a SENT speed limiter for vehicles with SENT throttle sensors, or a mechanical System 80 for cable-throttle vehicles.