1.1 Choosing LR, MR, HR, HC or MC
Key Takeaways
LR covers rigid vehicles above 4.5 t and up to 8 t GVM, and vehicles up to 8 t seating more than 12 adults including the driver.
MR covers two-axle rigid vehicles above 8 tonnes GVM; HR covers rigid vehicles above 8 tonnes with three or more axles, including articulated buses.
HC covers semi-trailers and rigid vehicles towing trailers above 9 tonnes GVM; MC covers B-doubles and other multi-combinations.
Read the vehicle before selecting the licence
A heavy vehicle knowledge question may describe a truck without naming its licence class. Start with the configuration: is it one rigid vehicle, a prime mover with a semi-trailer, a rigid truck towing a heavy trailer, or a combination with several trailers? Then use rated mass and axles. Paintwork, cargo type and the driver’s job title do not determine the class.
Gross Vehicle Mass (GVM) is the manufacturer’s maximum loaded mass rating for the vehicle. It is not the weight shown by a weighbridge on today’s empty trip. Unloading a truck does not turn its required licence into a lower class. Gross Combination Mass (GCM) is the manufacturer’s maximum rating for the towing vehicle and its combination. Licence classification and legal loading are separate checks: an appropriate licence does not authorise overloading.
The class hierarchy
| Class | Principal vehicle entitlement | Trailer boundary |
|---|---|---|
| LR — Light Rigid | Rigid vehicle above 4.5 t and up to 8 t GVM, or vehicle up to 8 t seating more than 12 adults including driver | Trailer not above 9 t GVM |
| MR — Medium Rigid | Rigid truck or bus above 8 t GVM with two axles | Trailer not above 9 t GVM |
| HR — Heavy Rigid | Rigid vehicle above 8 t GVM with three or more axles; articulated bus | Trailer not above 9 t GVM |
| HC — Heavy Combination | Prime mover and semi-trailer; rigid vehicle towing a trailer above 9 t GVM | Heavy combination entitlement |
| MC — Multi Combination | B-double and other multi-combination vehicles | Multiple combination entitlement |
LR also includes vehicles up to 8 t GVM seating more than 12 adults including the driver, even when their GVM is 4.5 t or less. Do not decide that every minibus is a car simply because its mass is low. Passenger seats and the licence definitions still matter. Conversely, axle count alone does not make a rigid vehicle above the LR mass range: assess mass first, then the MR/HR distinction.
A rigid vehicle carries its body and load on one chassis. An articulated bus has a pivoting passenger body, but it is specifically included in HR; it is not classified as a prime mover and semi-trailer just because it bends. A semi-trailer transfers part of its weight to the towing vehicle through the fifth wheel. A dog trailer has axle groups at its front and rear; a pig trailer has its axle group near the middle. Those trailer designs affect handling and loading, but a heavy trailer behind a rigid truck still requires the relevant combination entitlement.
Work through the boundaries
Consider a two-axle rigid delivery truck rated at 7.8 t. Its mass lies in LR, regardless of whether it carries furniture or refrigerated food. A two-axle rigid rated at 10 t moves into MR. A three-axle rigid rated at 24 t requires HR. If that HR truck tows a trailer rated above 9 t, the driver needs HC for the combination even when the trailer happens to be empty.
Now consider a prime mover towing one semi-trailer. Choose HC from its configuration rather than counting tyres. If a second semi-trailer is attached through the first trailer’s fifth wheel to form a B-double, the class is MC. An unladen converter dolly is a specific HC exception: it may accompany the handbook’s qualifying prime-mover/semi-trailer or rigid/heavy-trailer combination. A prime mover towing a dolly and one semi-trailer is also within HC. Do not classify every additional dolly as an MC combination; distinguish these expressly included arrangements from a combination carrying another loaded trailer. Route permission for that B-double is a separate issue; an MC licence does not give unrestricted road access.
A higher heavy vehicle class normally includes lower classes in the national hierarchy. That is useful when an HC driver operates an HR rigid for a different shift. However, read the actual licence conditions. An automatic or synchromesh restriction may prevent driving a non-synchromesh vehicle even though the class letter is sufficient. An ancillary passenger-service authority, dangerous goods licence or access permit can also be needed in addition to the vehicle class.
A reliable classification routine
- Identify each vehicle unit and whether the vehicle is rigid or articulated.
- Read the GVM ratings rather than guessing from appearance or today’s load.
- For a rigid vehicle above 8 t, distinguish two axles from three or more.
- Check whether a trailer exceeds the 9 t class boundary.
- Count the combination units and identify a B-double or other multi-combination.
- Check gearbox conditions and any separate operating authority.
A licence question and a mass-limit question may use the same numbers for different purposes. The 4.5 t threshold identifies heavy vehicles in many rules; 8 t separates LR from larger rigid classes; 9 t is a trailer entitlement boundary. None is a universal axle mass allowance. Keep each number attached to its definition.
Key decisions
Use the rated vehicle and its configuration to select the class. Treat trailer attachment as a fresh entitlement check, retain every applicable licence condition, and check route access independently when the configuration changes.
Official sources
Heavy vehicle licence classes and conditions; official handbook, Chapter 1. Sources checked 10 October 2026.
An HR rigid truck is towing an empty trailer rated at 12 tonnes GVM. Which class is needed for that combination?
HC
MR because the trailer is empty
HR because the towing vehicle is rigid
LR because only the actual trailer mass matters
Sections you finish are checked off in the contents.