Regulation 7 of the Road Vehicles (Construction and Use) Regulations 1986 (SI 1986/1078) (“Reg 7”) sets the principal maximum overall length limits for specified vehicle classes and combinations.
It also modifies those limits for certain specialist operations, notably showman’s vehicles.
Additionally, it disapplies certain Table limits altogether in defined scenarios, notably exceptional-length indivisible loads, breakdown recovery, certain older low loaders and (since 2022) elongated cabs on N2/N3 vehicles.
It is important to understand the exemptions and carve-outs to better determine what Regulation 7 permits and does not permit.
In the past year, I have dealt with cases in which investigating officers misunderstood the permitted length limit under Regulation 7 due to failing to consider applicable exemptions.
Regulation 7 is often treated as a simple “length table”.
In practice, it is a structured scheme consisting of:
- Default maxima
- Targeted disapplications for specialist operations
- Backstop requirements (particularly Reg 7(5) and (9) linked to Schedule 12)
The default rule: comply with the Table unless Reg 7 says otherwise
Reg 7(1) provides that, subject to paragraphs 7(2) to (6), the overall length of a vehicle or combination in a class in the Table must not exceed the maximum length stated for that class.
For combinations, overall length is calculated in accordance with Reg 81(g) and (h).
A copy of the Table (at the time of writing) is below.
| Item |
Class of vehicle |
Maximum length (metres) |
| |
Vehicle combinations |
|
| 1 |
A motor vehicle (other than a motor vehicle such as is mentioned in item 1A) drawing one trailer which is not a semi-trailer. |
18.75 |
| 1A |
Subject to paragraph (3C), a motor vehicle manufactured before 1st June 1998 and drawing one trailer, where the combination does not meet the requirements of paragraph (5A) and the trailer is not a semi-trailer. |
18 |
| 2 |
An articulated bus. |
18.75 |
| 2A |
A bus drawing a trailer. |
18.75 |
| 3 |
An articulated vehicle, the semi-trailer of which does not meet the requirements of paragraph (6) and is not a low loader. |
15.5 |
| 3A |
An articulated vehicle, the semi-trailer of which meets the requirements of paragraph (6) and is not a low loader. |
16.5 |
| 3B |
An articulated vehicle, the semi-trailer of which is a low loader. |
18 |
| 3C |
An articulated vehicle, the semi-trailer of which meets the requirements of paragraph (6), is not a low loader and is carrying one or more containers or swap bodies up to a total maximum length of 45 feet as part of an intermodal transport operation. |
16.65 |
| |
Motor vehicles |
|
| 4 |
A wheeled motor vehicle [other than a bus. |
12 |
| 4A |
A bus with two axles. |
13.5 |
| 4B |
A bus with more than two axles. |
15 |
| 5 |
A track-laying motor vehicle. |
9.2 |
| |
Trailers |
|
| 6 |
An agricultural trailed appliance manufactured on or after 1st December 1985. |
15 |
| 7 |
A semi-trailer manufactured on or after 1st May 1983 which does not meet the requirements of paragraph (6) and is not a low loader. |
12.2 |
| 7A |
A composite trailer drawn by: |
14.04 |
| |
A goods vehicle being a motor vehicle having a maximum gross weight exceeding 3500kg. |
|
| |
An agricultural motor vehicle. |
|
| 8 |
A trailer (not being a semi-trailer or composite trailer) with at least 4 wheels, which is: |
12 |
| |
Drawn by a goods vehicle being a motor vehicle having a maximum gross weight exceeding 3500kg |
|
| |
An agricultural trailer. |
|
| 9 |
Any other trailer not being an agricultural trailed appliance or a semi-trailer. |
7 |
The exemptions in Reg 7 generally operate in one of two ways:
- Substitution of a different maximum length (a modified limit)
- Disapplication of one or more Table items (meaning that the specific Table length cap does not apply to that case)
Modified limit: showman’s vehicle with living accommodation trailer (Reg 7(2))
Reg 7(2) applies where a motor vehicle draws one trailer and:
- the motor vehicle is a “showman’s vehicle” (as defined by reference to paragraph 7 of Schedule 3 to the 1971 Act) and
- the trailer is used primarily as a living accommodation and is not also used for the carriage of goods/burdens not needed for the residence.
If those conditions are met:
- Item 1 (motor vehicle drawing one non-semi-trailer) applies with 22m substituted for the normal limit and
- Item 1A does not apply.
Disapplications for combinations: when Items 1, 1A, 3, 3A and 3B do not apply (Reg 7(3))
Reg 7(3) provides that Items 1, 1A, 3, 3A and 3B of the Table do not apply to the following:
- Exceptional-length indivisible loads (Reg 7(3)(a)) – A vehicle combination that includes a trailer constructed and normally usedfor the conveyance of indivisible loads of exceptional length.
- Breakdown recovery (Reg 7(3)(b)) – A vehicle combination consisting of a broken-down vehicle (including an articulated vehicle) being drawn by a motor vehicle in consequence of a breakdown.
- Older low loaders (Reg 7(3)(c)) – An articulated vehicle where the semi-trailer is a low loader manufactured before 1 April 1991.
- Elongated cabs on N2/N3 vehicles (Reg 7(3)(d)) – A vehicle combination that includes:
- a category N2 motor vehicle or
- a category N3 motor vehicle, with an elongated cab.
This is a disapplication of the particular Table items listed in Reg 7(3), not a general authorisation to disregard dimensional control.
The elongated cab concept should be considered alongside the separate elongated cab provision for motor vehicles in Reg 7(3D) (see below).
Disapplications for trailers: when Items 6, 7, 7A, 8 and 9 do not apply (Reg 7(3A))
Reg 7(3A) provides that Items 6, 7, 7A, 8 and 9 of the Table do not apply to:
- Exceptional-length indivisible load trailers (Reg 7(3A)(a)) – A trailer constructed and normally used for the conveyance of indivisible loads of exceptional length.
- Breakdown recovery: broken down vehicle being drawn (Reg 7(3A)(b)) – A broken down vehicle (including an articulated vehicle) being drawn by a motor vehicle in consequence of a breakdown.
- Specialist roadworks plant and planing machines (Reg 7(3A)(c)) – A trailer being:
- a drying or mixing plant designed for the production of asphalt/bituminous or tar macadam and used mainly for the construction, repair or maintenance of roads or
- a road planing machine so used.
Additional disapplication limited to Item 7 (semi-trailer rule) (Reg 7(3B))
Reg 7(3B) provides that Item 7 does not apply to
- a semi-trailer, which is a car transporter or
- a semi-trailer normally used on international journeys, any part of which takes place outside the United Kingdom.
Elongated cabs: motor vehicle length (Item 4) (Reg 7(3D) and Reg 7(10))
Reg 7(3D) disapplies Item 4 (12m limit for a wheeled motor vehicle other than a bus) in relation to:
- an N2 motor vehicle, or
- an N3 motor vehicle, with an elongated cab type approved in accordance with the referenced type approval provisions.
Reg 7(10) defines “motor vehicle of category N2” and “motor vehicle of category N3” by reference to Regulation (EU) 2018/858 categories.
Important constraints that operate alongside exemptions (Reg 7(4), 7(5) and 7(9))
The exemptions above do not sit in isolation.
Reg 7 contains “secondary” length controls that often become decisive for longer combinations.
Limits on trailer lengths in multi-trailer outfits (Reg 7(4))
Where a motor vehicle draws:
- Two trailers – only one trailer may exceed 7m overall length
- Three trailers – none may exceed 7m overall length
This restriction is separate from the Table maxima and is often overlooked.
Additional rules for two or more trailers, or exceptional-length indivisible load trailer combinations (Reg 7(5))
Where a motor vehicle is drawing:
- Two or more trailers, or
- One trailer constructed and normally used for the conveyance of indivisible loads of exceptional length,
then:
- The overall length of the motor vehicle must not exceed 9.2m and
- The overall length of the combination must not exceed 25.9m, unless the conditions specified in Schedule 12 paragraphs 1 and 2 have been complied with.
For exceptional-length movements, Reg 7(5) is a key gateway provision.
Beyond 25.9m, compliance with Schedule 12 paragraphs 1 and 2 becomes essential.
Trailers over 18.65m: Schedule 12 compliance is mandatory (Reg 7(9))
Reg 7(9) creates a stand-alone prohibition.
No person may use (or cause or permit to be used) a trailer with an overall length exceeding 18.65m unless the requirements of Schedule 12 paragraphs 1 and 2 are complied with.
Semi-trailer “requirements” and measurement provisions (context for exemptions and classification)
Although not exemptions, Reg 7’s internal definitions affect whether a vehicle falls into one Table item or another, which can affect whether an exemption is even needed.
Reg 7(6) sets requirements for a semi-trailer (kingpin-to-rear distance and forward projection limits), with specific limits for car transporters and intermodal container operations.
Reg 7(6A) clarifies measurement for the purposes of Reg 7(5A), including treatment of a wall bounding the loading area and disregarding coupling fittings when measuring the gap between motor vehicle and trailer.
Reg 7(7), 7(7A), 7(7B) provide further rules on measuring from the kingpin (including which kingpin position to use depending on the manufacture date) and defining “front” and “rear” planes for the relevant distances.
These provisions frequently become relevant in enforcement where an operator contends that a semi-trailer “meets the requirements” of Reg 7(6) (thereby attracting a different Table limit under Items 3A/3C rather than Item 3).
Compliance-focused summary: when length limits may be exceeded (or Table limits disapplied)
Reg 7 permits departures from the standard Table maxima in the following principal ways:
- Showman’s vehicle + living accommodation trailer – Modified maximum for Item 1 (Reg 7(2)).
- Exceptional-length indivisible loads – Disapplication of key Table items for combinations (Reg 7(3)(a)) and for trailers (Reg 7(3A)(a)), subject to other constraints including Reg 7(5) and Schedule 12 triggers.
- Breakdown recovery towing – Disapplication for combinations and trailers/broken down vehicles (Reg 7(3)(b), 7(3A)(b)) and special rules for towed articulated vehicles (Reg 7(8)).
- Older low loader articulated vehicles – Disapplication (Reg 7(3)(c)).
- Elongated cabs on N2/N3 vehicles – Disapplication for certain combinations (Reg 7(3)(d)) and for the N2/N3 motor vehicle length limit (Reg 7(3D)), with type approval referenced.
Concluding remarks
Regulation 7 is often treated as a simple “length table”.
In practice, it is a structured scheme: (i) default maxima, (ii) targeted disapplications for specialist operations, and (iii) backstop requirements (particularly Reg 7(5) and (9) linked to Schedule 12).
For operators managing abnormal or specialist movements, the most common risk is assuming that a Table disapplication equates to “no length rules”, when Reg 7’s additional constraints and Schedule 12 conditions may still control the movement.
Our specialist team can support you with compliance awareness so that you do not get caught out. Contact James Edes today for help.