In 2015 the laws on tractor speeds and weights, which had been in place since the 1980s, changed.

National Association of Agricultural Contractors (NAAC) chief executive Jill Hewitt answered our questions on the updated rules for contractors and farmers in England, Scotland and Wales.

How fast can I drive my tractor and trailer on the road?

A conventional agricultural tractor towing an agricultural trailer can travel up to 40kph (approximately 25mph) on the road. This is an increase from the previous maximum permitted speed of 32kph (about 20mph).

It is important to emphasise that this increase only applies to agricultural tractors towing a trailer. Tractors pulling what is called an “agricultural trailed appliance” (a baler or crop sprayer, for example) must still observe the 20mph limit.

See also: Opinion – a message to motorists stuck behind my tractor

The maximum width of a tractor and trailer travelling to the new limit of 25mph is 2.55m.

What about larger tractors and other big agricultural machines, such as combines?

The speed increase does not apply to other agricultural machines such as sprayers and combines. Also, wider tractors over 2.55m and under 3.5m (and that includes the width of what you’re towing, too) are still restricted to the 20mph limit.

However, further changes to the legislation are being considered under phase two of the review.

Other agricultural machines between 3.5m and 4.3m wide continue to be limited to a 12mph
top speed.

Also, you will need to notify the police and have an escort vehicle for any journey.

How does this affect higher specification tractors which have already been allowed to travel to 40mph?

Higher specification tractors, such as the JCB Fastrac (pictured below) and Mercedes Unimog have the braking, suspension and other special requirements to qualify for the “fast” tractor classification with its 64kph (40mph) speed limit.

Tractors that have previously been allowed to travel at higher speeds under the Road Vehicles (Construction and Use) Regulation 1986 (as amended) aren’t affected by the recent changes to the law – provided the higher technical standards continue to be met.

What is the combined weight limit for a tractor and trailer combination?

The maximum combination weight of a tractor and single trailer has increased from 24.39t to 31t. However, the maximum laden weight of trailers remains unchanged at 18.29t. This includes three-axle trailers with road-friendly suspension and top-notch brakes.

Why has the trailer weight not increased?

This significant increase in gross train weight will allow bigger tractors, up to 6.61t heavier, to pull laden trailers more safely this harvest.

It is more than 28 years since this legislation was last reviewed and in that time, the industry has changed almost beyond recognition.

The previous 24.39t limit was forcing farmers and contractors to put small tractors on the front of larger trailers to keep anywhere close to the legal weight limit. The increase to 31t is helping to tackle this problem in the short term as negotiations continue.

While it is all frustratingly slow for farmers, this is a step in the right direction for more closely aligning the legal position to the reality of our industry.

Do I need to have my tractor and trailer tested to go to 31t or to travel to 40kph?

No. There are no additional requirements to allow you to use the increased weight and speed and there are no plans to introduce a test at this level. However, you must still ensure your vehicle is roadworthy to stay within the law.

The Provision and Use of Work Equipment Regulations apply to any machinery used at work, requiring it to be properly repaired and in working order. That means you need to do regular maintenance checks on all parts – including brakes, hydraulic hoses and pto guards.

Tractors and trailers driven on public roads must also comply with the Construction and Use Regulations 1986 and The Road Traffic Act and must be roadworthy.

If you’re stopped, any defects found can open the driver and owner to prosecution by road traffic law enforcement agencies or the police.

The British Agricultural and Garden Machinery Association (Bagma) has a useful vehicle health check scheme, which can be downloaded from the resources section.

How old does the driver need to be to drive a tractor/trailer combination to the higher speeds and weight?

No changes were made to the law regarding age and training. So a 16-year-old can drive a tractor provided they have taken a category F test (commonly known as the tractor test).

However they can only take tractors and trailers on the road that are less than 2.45m wide and have two wheels, or four close-coupled (tandem) wheels.

Drivers over the age of 17 with either a category F (tractor) or B (car) licence can drive tractor-trailer combinations on the road, although this does not apply to tracked vehicles.

Can I still use red diesel at the higher speeds and weight?

Yes, the rebated fuel legislation has not changed, so provided the tractor is being driven solely for agricultural use, and its role fits within the parameters of the legislation, nothing has changed.

Can I use my tractor and trailer for haulage?

Despite the increase in weight and speed, the industry should still not be using agricultural tractors solely for haulage.

As soon a pure haulage operation takes place the tractor can no longer be classed as an agricultural vehicle and operator licensing, driver hours and white diesel come firmly into play.

Farmers and contractors can, of course, use tractors for moving produce, as part of the agricultural operation, within current limitations for operator licensing.