Understanding 'Speed Limit Defencer' and Vehicle Speed Limiters
The term 'speed limit defencer' is an unusual phrase, likely referring to a device that enforces or limits a vehicle's speed, more commonly known as a speed limiter. These systems are integrated into vehicles to ensure they do not exceed a predetermined velocity, playing a significant role in road safety and regulatory compliance. Whether fitted as standard by manufacturers or as an aftermarket addition, understanding their function is paramount for fleet operators and drivers alike.
- Speed limiters restrict a vehicle's maximum velocity.
- They are critical for road safety and regulatory compliance.
- Systems can be factory-fitted or aftermarket solutions.
- Different regulations apply based on vehicle type and weight.
In essence, a speed limiter is a technological safeguard. It doesn't 'defend' against speed limits in the sense of evading them; rather, it actively prevents the vehicle from breaching a set speed threshold. This is particularly relevant for commercial vehicles, where regulations often mandate speed-limiting capabilities to reduce accident risks and promote fuel efficiency. The technology is designed to be unobtrusive during normal driving but becomes active when the vehicle approaches its designated maximum speed.
The concept is straightforward: a control unit monitors the vehicle's speed and, when the limit is reached, it signals other components, typically the engine's fuel system, to reduce power. This prevents acceleration beyond the set point. The driver can still brake or disengage cruise control, but the engine will not provide more power to exceed the limiter's set speed.
When Did Speed Limiters Become Common?
Mandatory speed limiters for certain classes of vehicles, particularly heavy goods vehicles (HGVs) and passenger transport vehicles, have been a regulatory requirement in many regions for decades. The European Union, for instance, introduced regulations requiring speed limiters on new heavy vehicles in the late 1990s. These regulations aimed to harmonise safety standards across member states and reduce the severity of accidents involving large vehicles. Over time, these requirements have evolved, becoming more stringent and encompassing a wider range of vehicles. For passenger cars, while speed limiters are not typically mandated by law, many modern vehicles incorporate them as an intelligent speed assistance (ISA) feature, which can either alert the driver to the speed limit or actively limit the vehicle's speed.
Types of Speed Limiter Technologies
When considering 'speed limit defencer' or speed limiter devices, it's important to recognise that technology has evolved significantly. The primary goal remains the same – controlling maximum vehicle speed – but the methods employed vary. These can range from simple mechanical governors to sophisticated electronic systems that integrate with other vehicle sensors.
Mechanical Governors
Historically, the earliest form of speed limiting involved mechanical governors. These are essentially centrifugal devices linked to the engine. As engine speed increases, weights within the governor fly outwards, and at a certain engine RPM (which corresponds to a specific road speed), they act on a mechanism to close the throttle, thus preventing further acceleration. While robust, mechanical governors offer less precision and flexibility compared to modern electronic systems and are less common in new vehicles.
Electronic Speed Limiters (ESLs)
The vast majority of modern speed limiting systems are electronic. An Electronic Speed Limiter (ESL) works by receiving speed input from the vehicle's speedometer sensor. A dedicated control unit, often part of the engine control unit (ECU) or a separate module, compares this speed to the pre-set limit. If the vehicle's speed reaches or exceeds this limit, the ESL sends signals to reduce engine power. This is typically achieved by adjusting the amount of fuel injected into the engine or by modifying the throttle position electronically. ESLs offer greater accuracy, better integration with other vehicle systems like cruise control, and can be more easily reprogrammed if speed limits need to be adjusted (within legal parameters).
Intelligent Speed Assistance (ISA) Systems
Intelligent Speed Assistance (ISA) represents a more advanced approach, often found in newer passenger cars. ISA systems go beyond simple limitation. They use cameras to read road signs and/or GPS data to identify the current speed limit. The system can then alert the driver (e.g., with an audible warning or a visual cue on the dashboard) or, in more advanced implementations, actively intervene. Active ISA systems can limit acceleration or even apply gentle braking to ensure the vehicle adheres to the detected speed limit. Drivers can usually override ISA systems, but their presence signifies a move towards proactive speed management integrated directly into the vehicle's driving assistance features.
The choice between these systems often depends on the vehicle type, its intended use, and the regulatory requirements in place. For commercial fleets, precise electronic control is standard, while for passenger cars, the trend is towards driver-assist features that offer flexibility.
The primary function of any speed limiter system is to enhance safety by ensuring vehicles operate within legally prescribed or operator-defined velocity parameters.
Integration with Other Vehicle Systems
Modern speed limiters are rarely standalone units. They are often integrated into broader vehicle management systems. For example, an Electronic Speed Limiter might work in conjunction with adaptive cruise control. While adaptive cruise control maintains a set speed and distance from the vehicle ahead, the speed limiter ensures the cruise control does not allow the vehicle to exceed a maximum, predefined speed. This level of integration means that changes to one system can sometimes affect others, making professional installation and maintenance vital.
Legal Requirements and Vehicle Classifications
Understanding the legal landscape is crucial when discussing speed limiters, as 'speed limit defencer' technologies are often mandated by law for specific vehicle categories. These regulations are designed to enhance road safety, particularly concerning heavier and larger vehicles that pose a greater risk to other road users.
Mandatory Speed Limiters in the UK and EU
In the United Kingdom and across the European Union, speed limiters are mandatory for certain classes of vehicles. These typically include:
- Heavy Goods Vehicles (HGVs) with a maximum authorised mass (MAM) exceeding 3.5 tonnes.
- Buses and coaches designed to carry more than 16 passengers (excluding the driver).
For these vehicles, speed limiters are set to specific maximum speeds: 90 km/h (approximately 56 mph) for most HGVs and 100 km/h (approximately 62 mph) for buses. These limits are not arbitrary; they are established based on extensive research into vehicle dynamics, braking distances, and the potential impact of large vehicles in collisions.
Different Speed Limits for Vans and Lighter Vehicles
While HGVs and buses have mandated limits, the situation for lighter commercial vehicles, such as vans, can differ. Standard vans (often weighing less than 3.5 tonnes MAM) are generally not subject to mandatory speed limiter installation. However, fleet operators may choose to fit them voluntarily for reasons of safety, fuel efficiency, and driver behaviour management. The general speed limits for vans on UK roads apply, for example, the national speed limit on single carriageway roads, dual carriageways, and motorways. It is worth noting that some larger, heavier vans may fall into the HGV category and therefore require a limiter.
Speed Limits on Different Road Types
Beyond the vehicle itself, speed limiters must operate within the context of various road speed limits. The national speed limit in the UK varies by road type and vehicle. For cars, these are generally 60 mph on single carriageways and 70 mph on dual carriageways and motorways. However, for vehicles subject to mandatory speed limiters (like HGVs), their fitted limiter speed will be lower than these general limits, ensuring they never exceed their regulated maximum, regardless of the road or signage.
It's essential for owners and operators to be aware of the specific regulations applicable to their vehicle type. This includes understanding the set speed of any fitted limiter and ensuring it is functioning correctly and has not been tampered with. Regular checks and maintenance are not just good practice; they are often a legal requirement, ensuring compliance with vehicle standards and road safety legislation.
Ensure you consult the latest government guidance or a qualified vehicle inspector to confirm the precise speed limiter requirements for your specific vehicle class and operating region.
How Speed Limiters Are Installed and Maintained
Considering a 'speed limit defencer' for your vehicle involves understanding the installation process and ongoing maintenance. While many modern vehicles come equipped with integrated electronic systems, aftermarket solutions are also available, particularly for commercial fleets or older vehicles not originally fitted with such technology.
Professional Installation is Key
For any vehicle that legally requires a speed limiter, or for those where its accurate function is critical for safety and compliance, professional installation is non-negotiable. This is because speed limiters interface directly with the vehicle's powertrain – specifically the engine's fuel injection or throttle control. Incorrect installation can lead to:
- Damage to the engine or electronic control units (ECUs).
- Inaccurate speed limiting, failing to meet legal requirements or safety standards.
- Compromised vehicle performance or drivability.
Qualified technicians, often found at specialist vehicle workshops or dealerships, possess the necessary diagnostic tools and knowledge to correctly install and calibrate these devices. They ensure the limiter is set to the legally required speed (e.g., 90 km/h for HGVs) and that it integrates seamlessly with the vehicle's existing systems without causing conflicts.
Aftermarket Speed Limiter Devices
For vehicles that do not have factory-fitted speed limiters, aftermarket devices can be installed. These can range from dedicated control modules that plug into the vehicle's CAN bus system to more complex systems requiring direct wiring. When choosing an aftermarket option, it's vital to select a reputable brand that meets relevant safety and certification standards for your region. Always confirm that the device is compatible with your specific vehicle make, model, and year. A common scenario is fitting limiters to vans or smaller commercial vehicles when a fleet operator wants to enforce stricter speed policies than general road laws dictate.
Maintenance and Checks
Speed limiters, like any critical vehicle component, require regular maintenance and checks to ensure they remain effective and compliant. This includes:
- Regular Inspections: vehicles subject to mandatory speed limiters often undergo specific inspections (such as MOTs in the UK) where the limiter's presence and functionality are verified.
- Diagnostic Checks: any warning lights on the dashboard related to engine management or cruise control systems should be investigated promptly, as they could indicate an issue with the speed limiter.
- Calibration Verification: If a vehicle's speed limiter is suspected of being inaccurate or has been tampered with, it needs to be recalibrated by a specialist. This process typically involves connecting diagnostic equipment to confirm the limiter is set to the correct legal speed.
Tampering with a speed limiter to exceed its set speed is illegal and carries significant penalties, including hefty fines and potential disqualification from driving. It also negates the safety benefits the device is intended to provide, increasing the risk of accidents and potentially invalidating insurance.
Benefits of Using Speed Limiter Devices
Beyond mere compliance with regulations, adopting speed limiter technology, often sought under terms like 'speed limit defencer', offers tangible advantages for vehicle operators and drivers. These benefits span safety, operational efficiency, and even financial savings.
Enhanced Road Safety
The most significant benefit is improved road safety. By preventing vehicles from exceeding a set speed, limiters dramatically reduce the kinetic energy involved in potential collisions. This means impacts are less severe, significantly lowering the risk of serious injury or fatality for occupants and other road users. For HGVs and buses, where speeds can have amplified consequences, this is particularly critical. A controlled speed also contributes to more predictable driving behaviour, allowing other road users to better anticipate the actions of larger vehicles.
Fuel Efficiency and Reduced Emissions
Operating vehicles at a controlled, consistent speed is generally more fuel-efficient than allowing wide fluctuations in speed. High speeds require significantly more engine power and thus more fuel. By capping the maximum speed, drivers are naturally encouraged to maintain a more economical pace, leading to substantial savings on fuel costs over time. This also translates to lower carbon emissions, contributing positively to environmental targets for businesses operating large fleets. Many studies have shown that a reduction in average speed, even by a few miles per hour, can yield considerable fuel savings.
Reduced Wear and Tear on Vehicle Components
Driving at excessive speeds puts greater strain on a vehicle's engine, brakes, and tyres. The constant need for higher power output, more aggressive braking, and increased tyre friction accelerates wear and tear. By limiting maximum speeds, the overall stress on these components is reduced. This can lead to longer component lifespans, fewer unexpected breakdowns, and lower maintenance costs, contributing to a better total cost of ownership for fleet vehicles.
Improved Driver Behaviour and Reduced Fines
Speeding is a leading cause of traffic accidents and is associated with numerous speed limit fines uk penalties. For commercial drivers, accumulating too many points or incurring significant fines can jeopardise their livelihood. Speed limiters effectively remove the temptation or possibility of speeding, fostering a culture of compliance. This not only prevents fines but also instills more disciplined driving habits, which can carry over to other aspects of their driving. For fleet managers, this provides peace of mind and reduces administrative burdens associated with managing driver infringements.
When setting speed limits for a fleet, consider a slightly lower threshold than the legal maximum to maximise fuel savings and safety, while still allowing for efficient journey times.
Compliance with Regulations
For HGVs, buses, and coaches, speed limiters are not optional; they are a legal requirement. Ensuring your vehicle is fitted with and correctly maintains a functional speed limiter guarantees compliance, avoiding penalties, vehicle impoundment, and potential prosecution. This regulatory adherence is fundamental for any professional transport operation.
When Speed Limiters Are Not Mandated: Voluntary Use
While certain vehicle types, like HGVs and buses, are legally obliged to have speed limiters, many other vehicles, including most passenger cars and lighter vans, are not. However, this doesn't mean speed limiting technology is irrelevant for these vehicles. Voluntary adoption can still offer substantial benefits.
Fleet Management and Company Policies
Many businesses that operate fleets of cars or lighter commercial vehicles choose to fit speed limiters or use vehicles equipped with Intelligent Speed Assistance (ISA) as part of their corporate responsibility and safety policies. Implementing a company-wide speed policy, enforced by technology, can significantly reduce the risk of accidents involving employees. It also provides a clear framework for driver behaviour and can be a key factor in reducing insurance premiums. For a company, this proactive approach demonstrates a commitment to safety that extends beyond minimum legal requirements.
Fuel Economy and Cost Savings
Even for smaller vehicles, excessive speed is a major contributor to poor fuel economy. Driving at 70 mph instead of 60 mph can increase fuel consumption by 10-15% or more, depending on the vehicle. For a business with a large fleet, or even for an individual who covers significant mileage, implementing a speed limiter set at a moderate, economical speed can lead to substantial savings on fuel. This also aligns with environmental goals by reducing the vehicle's carbon footprint.
Driver Training and Behaviour Modification
For new or less experienced drivers, or those who habitually exceed speed limits, a speed limiter can serve as an effective training tool. It helps them develop a better sense of appropriate speed and can prevent them from inadvertently exceeding limits, especially on unfamiliar roads. While ISA systems offer alerts, a physical limiter provides a concrete boundary that reinforces the desired behaviour over time, reducing the likelihood of future speeding incidents even when the limiter is eventually removed or overridden.
Specific Use Cases
There are particular scenarios where voluntary speed limiting is highly beneficial:
- New Drivers: To assist in developing safe driving habits.
- Company Cars: To enforce corporate safety policies and manage fuel costs.
- Rental Fleets: To prevent misuse or damage to vehicles by ensuring they are driven within reasonable speed parameters.
- High-Mileage Vehicles: To maximise fuel efficiency and minimise wear and tear on vehicles covering extensive distances.
When considering a voluntary speed limiter, it's important to choose a system that is appropriate for the vehicle and its intended use. For cars, modern ISA systems that offer alerts and optional active limitation are often preferred for their flexibility. For lighter commercial vehicles where a strict policy is needed, a more traditional electronic limiter might be considered. Always ensure that any installed device is certified and professionally fitted to avoid compromising safety or vehicle integrity.
Potential Downsides and Considerations
While the benefits of speed limiters are substantial, particularly for regulated vehicles, it's also important to consider potential drawbacks or factors that require careful management. These typically arise from the technology's limitations, the driver's experience, or practical usage scenarios.
Impact on Driving Dynamics and Response
For drivers accustomed to full control over their vehicle's acceleration, the intervention of a speed limiter can be jarring. When the limiter engages, the vehicle will stop accelerating, even if the driver presses the accelerator pedal further. This can feel like a loss of power or responsiveness, which might be disconcerting, especially if the driver needs to accelerate quickly to avoid a hazard or merge into fast-moving traffic. While most modern systems are smooth, older or less sophisticated limiters can be quite abrupt, potentially affecting the vehicle's momentum.
Misinterpretation of Speed Limits
Electronic speed limiters are programmed to a specific maximum speed. This programmed speed is a fixed value and does not change with the road speed limit. For example, an HGV limited to 90 km/h must adhere to this, even if the national speed limit on a particular dual carriageway is 70 mph (approximately 112 km/h). This means the limiter ensures compliance with the *vehicle's* maximum permitted speed, not necessarily the *road's* current speed limit, which can sometimes be higher. This can lead to drivers of limited vehicles being significantly slower than other traffic, potentially causing congestion or frustration, though it does promote safer interactions.
Risk of Tampering and Malfunction
Despite regulations, there remains a risk of speed limiters being tampered with to bypass or disable them, especially in older or less scrupulous operations. This is illegal and dangerous. Furthermore, like any electronic system, speed limiters can malfunction. This could result in the limiter failing to engage, or conversely, engaging prematurely or erratically. Regular checks and maintenance are essential to identify and rectify such issues promptly. Any warning lights or unusual behaviour from the vehicle's powertrain should be investigated immediately by a qualified technician.
Cost of Installation and Maintenance
While often a legal requirement or a sound investment for fleets, the initial cost of installing a speed limiter device or purchasing a vehicle with one integrated can be a consideration. For aftermarket installations, costs can vary depending on the complexity of the system and the vehicle. Similarly, maintaining these systems, including periodic calibration checks and diagnostics, adds to the overall running costs. However, these costs are often offset by savings in fuel, reduced accident rates, and lower insurance premiums over the vehicle's lifespan.
Driver Acceptance and Training
Not all drivers readily accept speed limiting technology, particularly if they are used to having unrestricted control. Some may feel frustrated by the imposed limitations. Effective driver training is crucial. This training should explain why the limiter is fitted, how it works, its benefits, and how to drive smoothly with it engaged. Educating drivers on the importance of adhering to speed limits, both for safety and legal reasons, can improve their acceptance and cooperation.
Comparing Speed Limiter Solutions
When investigating 'speed limit defencer' options or simply looking to manage vehicle speeds, a comparative approach is beneficial. The 'best' solution depends heavily on the vehicle type, legal obligations, and operational priorities. Here’s a breakdown of factors to consider when comparing different speed limiting technologies and approaches.
Mandatory vs. Voluntary Systems
The first distinction is whether a speed limiter is legally required. For HGVs and buses over a certain weight or passenger capacity, fitted and certified speed limiters are mandatory. In this case, the comparison is less about *whether* to fit one and more about choosing a reputable installer and ensuring the device meets all regulatory standards (e.g., ECE R89 certification in Europe). For vehicles where it's not mandatory, the decision is voluntary and driven by other factors.
Technology Types: Governor vs. Electronic vs. ISA
Mechanical Governors: Simple, robust, but less precise. Often found in older vehicles. Not suitable for modern requirements demanding accuracy and integration.
Electronic Speed Limiters (ESLs): The standard for mandated applications and commercial fleets. Offer accuracy, reliability, and integration capabilities. They directly control engine output.
Intelligent Speed Assistance (ISA): Primarily for passenger cars, and increasingly becoming standard. Utilise camera and GPS data to identify road speed limits. Offer variable modes: alert-only, speed warning, or active speed limitation. More flexible for passenger vehicles but may not meet the strict 'fixed limit' requirements for commercial transport.
Installation and Certification
For mandated systems, look for devices and installers certified to relevant standards. This ensures the equipment has been tested and approved for use on public roads. For aftermarket solutions on non-mandated vehicles, the focus shifts to reputable brands, quality of installation, and compatibility with your vehicle's systems. A poorly installed device can cause more problems than it solves.
Features and Customisation
Fixed Speed Limit: Standard for mandatory limiters. The speed is set and generally cannot be altered without recalibration.
Adjustable Limits: Some systems allow for multiple pre-set speeds or adjustment within a range, useful for varied fleet operations or when a vehicle is used for different purposes.
Driver Override: Most systems allow drivers to temporarily override the limiter (e.g., by braking), but the system will re-engage when the accelerator is pressed again to reach the set limit. Some ISA systems allow for full manual override by the driver. The level of override available is a key feature to compare based on operational needs.
Cost vs. Benefit Analysis
When speed limiters are not mandatory, a cost-benefit analysis is crucial. Evaluate the cost of purchase and installation against:
- Projected fuel savings.
- Potential reduction in accident costs (repairs, insurance claims, downtime).
- Avoidance of speed limit fines uk penalties.
- Improved driver safety and compliance.
For many businesses, the investment in speed limiting technology, even if voluntary, can offer a strong return through operational efficiencies and risk reduction.
Where to Check for Options
To find specific speed limiter devices and installers, you should consult:
- Vehicle Manufacturers: For factory-fitted options or approved dealer services.
- Specialist Fleet Management Companies: They often offer integrated solutions including speed limiting.
- Approved Vehicle Workshops: Look for workshops that specialise in commercial vehicle modifications or diagnostics.
- Online Retailers (with caution): If purchasing aftermarket kits, ensure they are from reputable suppliers and clearly state their certification and compatibility. Always arrange for professional installation.
When comparing, always ask about the device's certification, warranty, installation process, and the after-sales support available.
The Future of Speed Limiters and Vehicle Technology
The landscape of vehicle technology is constantly evolving, and speed limitation is no exception. What started as a mechanical governor has transformed into sophisticated electronic systems, and the trajectory suggests even more integrated and intelligent solutions ahead. The concept of 'speed limit defencer' is rapidly becoming synonymous with advanced driver assistance and autonomous driving features.
Increased Integration with ADAS
Advanced Driver Assistance Systems (ADAS) are becoming standard in new vehicles. Features like adaptive cruise control, lane-keeping assist, and automatic emergency braking are already commonplace. Speed limiters are increasingly being integrated into these systems. Intelligent Speed Assistance (ISA) is a prime example, where the vehicle uses cameras and GPS data to not only detect the current speed limit but also to actively manage the vehicle's speed accordingly. Future systems will likely offer more seamless integration, where the vehicle can dynamically adjust its speed to match road limits, traffic flow, and even navigation route recommendations.
Connectivity and V2X Communication
Vehicle-to-everything (V2X) communication is a burgeoning technology that will profoundly impact road safety. This allows vehicles to communicate with other vehicles (V2V), infrastructure (V2I), and pedestrians (V2P). Imagine a future where a vehicle receives real-time information about upcoming speed limit changes, temporary roadworks, or hazardous conditions directly from road infrastructure. This data can then be used by the vehicle's onboard computer to proactively adjust speed, potentially even before a human driver or the vehicle's onboard sensors can detect the change. This cooperative approach to speed management promises a significant leap in safety and efficiency.
Autonomous Driving
As vehicles move towards higher levels of autonomy, speed control becomes an intrinsic part of the driving system. Autonomous vehicles will inherently manage their speed based on programmed parameters, navigation data, environmental conditions, and communication with other road users and infrastructure. For fully autonomous cars, the concept of a driver-imposed 'speed limit defencer' becomes moot, as the vehicle's AI will be responsible for all speed management decisions, prioritising safety and efficiency according to its programming and real-time data.
Data-Driven Road Safety
The vast amounts of data generated by modern vehicles, including speed, location, and braking patterns, can be anonymised and aggregated to inform road safety strategies. By analysing this data, authorities and manufacturers can identify high-risk areas, understand common driving behaviours, and develop more effective speed limit policies or technological interventions. This data-driven approach supports continuous improvement in how vehicles interact with the road environment.
While 'speed limit defencer' might sound like a niche aftermarket product, it represents a fundamental aspect of vehicle safety and control that is deeply embedded in the technological advancements shaping the future of transportation. From mandated commercial vehicle limiters to the intelligent systems in passenger cars and the autonomous capabilities of tomorrow, the focus remains on making roads safer and driving more efficient.
Frequently Asked Questions About Speed Limiters
Here are answers to common questions regarding speed limiter devices, often referred to by searchers as 'speed limit defencers'.
What is the purpose of a speed limiter?
A speed limiter's primary purpose is to restrict a vehicle's maximum speed to a predetermined level. This enhances road safety by preventing excessive speeds, reduces fuel consumption, and ensures compliance with legal requirements for certain vehicle types.
Are speed limiters mandatory in all vehicles?
No, speed limiters are only mandatory for certain heavy vehicles in the UK and EU, such as HGVs and buses over a specific weight or passenger capacity. Most passenger cars and lighter vans do not have mandatory speed limiters, though many feature Intelligent Speed Assistance (ISA) systems.
What is the typical speed limit for an HGV?
In the UK and EU, HGVs with a maximum authorised mass exceeding 3.5 tonnes are typically required to have their speed limiters set to a maximum of 90 km/h (approximately 56 mph). Buses designed for more than 16 passengers may have a limit of 100 km/h (approximately 62 mph).
Can a speed limiter be removed or bypassed?
It is illegal to tamper with or remove a mandatory speed limiter. Doing so can result in significant fines, prosecution, and potential vehicle impoundment. It also compromises safety and may invalidate insurance.
How does Intelligent Speed Assistance (ISA) differ from a traditional speed limiter?
ISA systems use cameras and GPS to identify current road speed limits and can alert the driver or actively limit speed. Traditional speed limiters are programmed to a fixed maximum speed and do not dynamically adjust to different road limits.
What happens if my speed limiter malfunctions?
If you suspect a speed limiter malfunction, such as it not engaging or engaging erratically, you should stop driving the vehicle if it's unsafe and seek immediate professional diagnosis from a qualified technician. Driving a vehicle with a faulty mandatory speed limiter is illegal.
Can a speed limiter be reprogrammed to a higher speed?
Reprogramming a speed limiter to a speed higher than legally permitted for that vehicle class is illegal. Only certified technicians can recalibrate or adjust speed limiters, and this must be done to comply with relevant regulations.