Farm Machinery Specifications - keep within the law
As harvest gets underway across the country, it is important to remember
where the law stands with regards to agricultural machinery.
Farm machinery has increased in size dramatically since the Road Traffic Act was introduced; however it
is still a legal requirement to keep within the dimensions and weights specified within the Act.
weight restrictions

The maximum gross weight of an agricultural tractor is
24,390kg.

The maximum weight for an agricultural tractor and
trailer is also 24,390kg.
In reality a modern 140hp tractor can weigh 10,500kg and
an un-leaden 14t trailer can be an additional 4,800kg. If
the trailer were filled to capacity, it would be feasible for
the gross train weights of 24,390kg to be exceeded by
4,000 to 5,000kg.
Many growers are using trailers and carting tractors that
are significantly larger than this example. Being caught
overweight may result in fines or a court summons
depending on the size of the excess weight.
length restrictions
The maximum length of an agricultural vehicle is 12m;
however this is only likely to be exceeded by sugar beet
harvesters and other self-propelled equipment. The
maximum length for a tractor and trailer is 18.75m.
However, should two trailers be coupled, this increases to
25.9m providing only one trailer is longer than 7m. It is
worth bearing in mind that the overall length of a 40ft
header trailer being pulled by a mid-range tractor will
measure close to the 18.75m maximum.
young drivers
It is also worth remembering that young drivers of
agricultural machinery have further restrictions placed on
them. A 16 year old, who has passed their tractor test is
limited to a maximum width of 2.45m until they are 17. A
previously legal tractor may become illegal for younger
drivers when wider or dual tyres are fitted. Younger drivers
are also not permitted to use a trailer with more than two
axles, unless they are close coupled. In reality this forbids
use of trailers with a turntable axle at the front, or use of a
dolly lead trailer on the road for under 17’s. A track laying
machine over 3.5t can only be operated by over 21’s with
a category H licence.
highway movements
During the peak of harvest it might be tempting to move
a combine between fields without much thought,
however there are further complications and restrictions
with the width of machinery. The maximum permissible
width for most agricultural machines travelling on the
highway is 2.55m. This can be increased if a 20mph speed
limit is adhered to. Many modern tractors are wider than
2.55m, especially when taking into account a possible
change of tyres for cultivations.
If the machine is wider than 3m, police notification is
required before movement. If the machine is 3.5m up to a
maximum width of 4.3m, this requires a 12mph speed limit,
police notification and an escort. Whilst most farmers
believe that they are complying with regulations relating
to width and the use of an escort when moving combines,
they may be falling foul of the laws restricting speed limits.
Most police forces will issue a dispensation to farmers and
contractors allowing the movement of oversize
agricultural machinery without prior notification. It is
important to note that this dispensation will only apply to a
25 mile radius of the normal operating base and for loads
up to 4.1m. Loads over 4.1m will still require police
notification.
Farmers and contractors should be aware that these
dispensations expire and will require reapplication on an
annual basis. Local restrictions may also apply to the
movement of abnormal loads on certain roads during the
hours of darkness.
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braking legislation
Tractor braking is also legislated. Tractors that travel below
20mph must have a braking efficiency of 25%. If a tractor
is to travel faster than 20mph it must comply with EEC
Directive 71/320. The regulations sets out that the vehicles
must have service, secondary and parking brakes and a
braking efficiency of at least 45%. When a trailer is being
used further complications are added. The regulations
state that the trailer brakes must be able to be applied
independently should the tractor’s brakes fail. A further
stipulation is that the trailer’s brakes must be applied
automatically if the tractor and trailer become
decoupled.
The Directive does not stipulate that air-brakes are
necessary; however most of the aforementioned
requirements can be met by use of air brakes. Most
tractor and trailer combinations do not comply with this
regulation, confirmation can be provided by the
manufacturer.
lighting
The regulations regarding agricultural machinery on the
highway are undoubtedly complex and arguably out of
date.
Whilst there is no tractor MOT at this time, it is every
operator’s responsibility to make sure that they are
compliant with the regulations. It is prudent practice to
make sure all lights on tractors and trailers are fully
operational and machinery is serviced regularly with
special attention being paid to brakes.
Should a tractor be involved in an accident whilst on the
road, the relevant authorities are likely to examine the
machinery involved in order to ascertain if the vehicle was
fit for the road. Insurance cover may also be jeopardised
should the machine be found to be in poor condition.
The views expressed in this Information Sheet are based on
the author’s current understanding of what the law means
and are not definitive. Only the courts may interpret
legislation definitively. If you are in any doubt about your
legal obligations, you should take independent legal
advice as this Information Sheet is not a substitute for such
independent legal advice.
Lighting is another important and often overlooked
aspect of farm machinery.
The requirement for lighting varies with age of machine
and maximum possible speed of the tractor. As a general
rule, if the machine is manufactured after 1986 and is
capable of travelling at more than 25mph, a full array of
front, rear and indicator lights are needed.
Tractors which do not exceed 25mph that are used on
dual carriageways must have an amber beacon fitted,
however it would be prudent to fit working beacons to all
machinery regardless of top speed and size of roads. If a
beacon is fitted, either voluntary or by regulation, it must
be at least 1.2m from the ground and be visible from a
reasonable distance in a full 360º around the tractor.
for further information or to discuss the issues raised
contact
Jonathan Colman
01636 642511
[email protected]
[email protected]
July 2013
Fisher German is a limited liability partnership, registered in England and Wales.
Registered number: OC317554
Registered office: 40 High Street, Market Harborough, Leicestershire LE167NX.
Regulated by RICS.
Fisher German LLP has tried to ensure accuracy and cannot accept liability for any errors,
fact or opinion. Please do not use this as all the advice needed to make decisions.
www.fishergerman.co.uk