Every HGV driver knows the truck will not go past its limiter. Fewer people in the industry think about the limiter as what it legally is: a piece of mandated safety equipment with its own fitting, calibration, sealing and maintenance requirements under the Construction and Use Regulations - regulation 36B specifically - sitting alongside brakes and tyres in the roadworthiness frame. Tamper with it and you are not tweaking a setting; you are dismantling a legal requirement.
The speed limiter rules apply to vehicles defined by their capability - vehicles that have, or would have without a limiter, a relevant speed above the thresholds. For the main HGV class the regulation is explicit: every vehicle to which it applies must be fitted with a speed limiter meeting the detailed requirements that follow. For newer goods vehicles the limiter must be set so the stabilised speed of the vehicle does not exceed 90 km/h; the older paragraph for earlier vehicles refers to a set speed not exceeding 60 mph, reflecting the era those vehicles come from.
The limiter is not just present; it must be calibrated, and limiters fitted to the main vehicle classes must comply with the technical annexes of the governing European directive as amended - the standards that define what a compliant limiter is. Sealing is part of the architecture: the rules address limiters sealed by authorised sealers, with special provision only for limiters fitted before 1 August 1992 to vehicles first used before that date, and for limiters sealed outside the United Kingdom. The point of sealing is the point of the whole system - the setting is not meant to be adjustable by anyone with a laptop and a motive.
Because the limiter is statutory equipment, it lives inside the maintenance system, not beside it:
The 90 km/h cap is the visible function, but the limiter’s deeper role is evidential. A fleet whose vehicles cannot physically exceed the cap has a structural answer to a whole class of speeding risk on motorways and dual carriageways. Conversely, a fleet where limiters have been interfered with has a structural liability: the first serious collision at speed turns the limiter setting into a forensic question, and “someone disabled it” becomes a conduct finding about the operator, not just the driver.
DVSA examiners and Traffic Commissioners both read limiter integrity as a culture marker. A sealed, correct, documented limiter says the maintenance system is real. Broken seals and unexplained settings say something else, loudly.
The speed limiter is one of the quiet successes of truck safety regulation - a cap that works because it is built in, sealed up and checked. Keep it that way, deliberately, on every single vehicle in the entire fleet, every time.