Are your HGV lights legal? DVSA warning on aftermarket lights and LED displays

Extra lights, warning signs and illuminated displays are increasingly common on modern HGVs.

Some are fitted for a practical reason. Others are intended to make a vehicle more visible, warn cyclists or pedestrians, improve safety while manoeuvring or simply personalise the truck.

But being available to buy does not automatically mean a product is legal to fit or use on a road-going vehicle.

In April 2026, DVSA warned that it had noticed a concerning increase in non-compliant and illegal lighting products fitted to commercial vehicles. The warning specifically covered vulnerable road user signs, decorative LED displays and blue warning beacons.

For operators, the issue is not just whether the lights work.

The colour, flash rate, position, mounting, visibility and way the device connects to the vehicle can all affect whether it is compliant.

This guide explains what HGV operators and drivers should check before fitting or continuing to use aftermarket lighting.

Why DVSA issued a warning about aftermarket lights

DVSA says it has seen an increasing number of vehicles fitted with lighting products that do not comply with the relevant requirements.

These include:

• illuminated vulnerable road user warning signs
• signs connected to direction indicators
• animated LED displays
• illuminated messages or emojis
• decorative coloured lights visible outside the cab
• blue warning beacons fitted to non-emergency vehicles
• devices mounted in unsafe positions
• equipment that protrudes from the vehicle

Some of these products may have been fitted with good intentions.

A driver may want to warn a cyclist that the vehicle is turning. An operator may want better visibility during reversing. A decorative display may appear harmless when fitted inside the cab.

However, the purpose of the product does not override the rules governing vehicle lighting.

A device can still create an MOT issue, attract roadside enforcement or pose a safety risk if it is the wrong colour, flashes incorrectly, resembles an emergency warning light or distracts other road users.

What are vulnerable road user warning signs?

Vulnerable road user, or VRU, signs are aftermarket devices intended to warn cyclists, pedestrians or motorcyclists about the movement of a large vehicle.

They are commonly fitted to the side or rear of an HGV or trailer.

Depending on the product, the device may:

• display an illuminated pictogram
• show a warning message
• flash when the indicator is activated
• produce an audible warning
• operate independently from the vehicle indicators
• combine a visual and audible alert

These devices can support safety around large vehicles, particularly during turns and manoeuvres.

But the way they operate matters.

When can a VRU sign become a direction indicator?

DVSA explains that when an illuminated VRU sign works in tandem with the vehicle’s indicators, it is treated as a direction indicator.

That means the device must meet the relevant requirements for direction indicators.

DVSA highlights two common areas of non-compliance:

• the light emits the wrong colour
• the light flashes at the wrong rate

Where the device operates together with the vehicle indicators, DVSA says the light should generally be amber, flash between 60 and 120 times per minute and operate in unison with the vehicle indicators.

A rear-facing light may need to be red, depending on its function and configuration.

Operators should not assume that a product is compliant simply because it was advertised as an HGV safety sign.

The installation and operation on the specific vehicle must also be correct.

Where should VRU devices be mounted?

DVSA advises that these devices should be fitted only to the sides or rear of the vehicle.

They should not:

• be mounted on side guards
• be attached to rear underrun protection devices
• increase the vehicle’s maximum permitted width
• protrude in a way that creates a danger
• use unsuitable reflective materials
• interfere with mandatory lights or markings
• obscure registration plates, reflectors or safety equipment

Mounting a device on a side guard can be particularly problematic.

Side guards and rear underrun devices have a safety function. Attaching protruding equipment to them can create an additional risk for cyclists, pedestrians or other road users.

Before installation, the operator should consider both the electrical operation and the physical mounting.

Could a non-compliant VRU sign fail an HGV MOT?

The outcome depends on the nature and severity of the problem.

DVSA says that where it finds only technical non-compliance involving a VRU sign at an annual test, an advisory notice may be issued.

However, where the device is fitted in a way that is clearly dangerous, the vehicle may fail the test.

DVSA gives the example of a device mounted on a side guard and protruding excessively. If it creates a safety risk, that can result in a test failure.

A flashing light of an incorrect colour may attract an advisory in some circumstances, but operators should not interpret this as permission to continue using a non-compliant product.

The vehicle may still face enforcement action at a roadside inspection, and circumstances can differ depending on the installation.

The safest approach is to correct the issue before the vehicle is used.

Are animated LED displays legal on an HGV?

Digital LED displays have become more visible on trucks.

They may show:

• animated eyes
• scrolling messages
• emojis
• moving patterns
• company messages
• driver names
• illuminated graphics

Some are mounted behind the windscreen. Others are placed in the rear of the cab but remain visible from outside.

DVSA says digital LED displays fall outside approved lighting standards and can create safety concerns.

The main risks include:

• distracting other drivers
• confusing road users
• competing with official road signs or signals
• showing colours that resemble regulated vehicle lights
• displaying moving images with no recognised road meaning
• restricting the driver’s view

DVSA’s practical advice is that any light displaying moving images is almost certainly illegal.

It also warns that a red light facing forwards is likely to be an offence.

Does switching the display off make it legal?

Not necessarily.

DVSA says action can be taken even when non-compliant decorative lights are switched off at the time of inspection.

The fact that a device is fitted and capable of displaying a prohibited or distracting light may still create a compliance issue.

This is important for drivers who assume they can install a decorative display and only switch it on at truck shows, depots or private sites.

If the vehicle is used on public roads with the equipment fitted, the operator should confirm that the installation itself is lawful.

The clearest DVSA advice is not to fit decorative LED displays to road-going vehicles.

Can an HGV use a blue warning beacon?

A normal HGV must not be fitted with a blue warning beacon simply to increase visibility.

Blue warning beacons and similar blue warning lamps are restricted to emergency vehicles and certain specifically authorised vehicles.

The Road Vehicles Lighting Regulations include restrictions on fitting devices that resemble blue warning beacons.

DVSA warns that police can take action where blue warning lights are fitted to an unauthorised HGV.

Possible consequences can include:

• a fine
• penalty points
• prosecution
• roadside enforcement action
• the requirement to remove the equipment
• additional scrutiny of the vehicle

Blue lights are widely recognised as an emergency signal. Using them on an ordinary commercial vehicle can mislead other road users.

This remains the case even when the driver believes the lights improve safety during reversing, loading or manoeuvring.

What about blue lights used only for reversing?

Some drivers fit blue flashing lights at the rear because they believe pedestrians respond more quickly to blue lights than to normal reversing lamps or alarms.

The intention may be to reduce risk.

However, DVSA’s published position is clear: unauthorised blue lights should be removed from road-going vehicles.

An operator needing additional warning during reversing should use appropriately approved equipment designed for that purpose.

That might include:

• compliant reversing lamps
• audible reversing warnings
• white-noise reversing alarms
• camera systems
• proximity sensors
• trained banksmen
• site-specific reversing controls
• approved amber warning equipment where legally appropriate

The solution should be selected after a proper risk assessment rather than by fitting equipment associated with emergency vehicles.

Can drivers rely on the seller saying a product is road legal?

No.

The fact that a product is offered online or in a vehicle accessory shop does not prove that it is legal for use on a public road.

A product may be intended for:

• private land
• exhibitions
• off-road use
• emergency vehicles
• specialist authorised vehicles
• markets outside Great Britain
• static display only

Some listings may use vague wording such as “road style”, “show use”, “universal fit” or “safety beacon” without confirming compliance for the intended vehicle.

Before buying or fitting equipment, operators should ask for clear technical information.

Useful questions include:

• What approval standard does the product meet?
• Is it approved for road use in Great Britain?
• What colour does it emit?
• What is the flash rate?
• Does it synchronise with the indicators?
• Where can it legally be mounted?
• Does it protrude beyond the body of the vehicle?
• Could it obscure another lamp, reflector or marking?
• Is professional installation required?
• Does fitting affect type approval or another vehicle system?
• Is documentary evidence of approval available?

Where the answer is unclear, obtain advice from a competent installer, maintenance provider or relevant authority before fitting it.

What should be checked during a daily walkaround?

Drivers should check all mandatory lamps and reflectors as part of the normal walkaround process.

Where aftermarket equipment is fitted, they should also look for obvious problems such as:

• loose or damaged light units
• cracked lenses
• exposed or damaged wiring
• incorrect operation
• lights showing the wrong colour
• signs flashing out of sequence
• equipment obscuring another lamp
• devices protruding from the vehicle
• displays obstructing the windscreen
• dashboard warnings following installation
• equipment becoming detached from its mount

Drivers should not attempt electrical diagnosis at the roadside unless they are trained and authorised.

The fault should be recorded and passed to the transport office or maintenance provider for assessment.

A digital walkaround check system can help the driver submit photos and notes so the office can see exactly what has been found.

Why aftermarket equipment should be recorded

Many operators keep detailed records of tyres, brakes, PMIs and repairs but have no clear list of aftermarket electrical accessories fitted to their vehicles.

That creates a blind spot.

The business should know:

• what equipment has been fitted
• which vehicle or trailer it is fitted to
• when it was installed
• who installed it
• what approval information was supplied
• how it is wired
• what maintenance it requires
• whether it has generated defects or warnings
• whether it was checked during the latest PMI
• whether it has been removed or replaced

This is particularly important where multiple drivers use the same vehicle or drivers are allowed to personalise their cabs.

A simple equipment policy can prevent unauthorised modifications.

Should drivers be allowed to fit their own lights?

Operators should have a clear rule covering driver-installed accessories.

Without a policy, drivers may fit:

• additional light bars
• illuminated name signs
• decorative cab lighting
• beacons
• electrical accessories
• windscreen-mounted displays
• charging equipment
• cameras or monitors

The risks go beyond lighting compliance.

Poor installation can cause:

• electrical faults
• overloaded circuits
• damaged wiring
• battery drain
• fire risk
• restricted visibility
• interference with vehicle systems
• insecure equipment in the cab
• warranty or insurance issues

A sensible policy should require authorisation before anything is drilled, wired, attached or displayed.

Installation should be completed or checked by a competent person.

What should operators do now?

Operators do not need to remove every aftermarket accessory automatically.

They should carry out a structured review.

1. Inspect every vehicle and trailer

Identify any additional lights, illuminated signs, beacons, displays or warning devices that were not part of the original vehicle specification.

Include equipment inside the cab if it is visible outside.

2. Check how each device operates

Record:

• light colour
• flash pattern
• activation method
• connection to indicators
• visibility from the front, side and rear
• mounting location
• physical projection from the vehicle

3. Obtain installation and approval information

Ask the supplier or installer for documentation confirming the product’s intended use and applicable approval.

Do not rely only on an online product description.

4. Remove clearly prohibited equipment

Unauthorised blue warning beacons and displays showing moving or distracting images should not remain fitted to road-going HGVs.

5. Review VRU warning devices

Check the colour, flash rate, synchronisation, mounting and physical position.

Pay particular attention to devices attached to side guards or underrun protection.

6. Add aftermarket equipment to maintenance checks

Ensure the relevant equipment is included in PMI and defect-reporting processes.

7. Brief drivers

Explain that equipment being available for sale does not prove it is legal to use.

Drivers should report new accessories before fitting them.

8. Keep evidence

Store invoices, product specifications, approval documents, installation records and repair details with the vehicle record.

What happens at a roadside inspection?

DVSA examiners can inspect the vehicle’s lamps, reflectors, attachments, condition and other safety-related equipment during a roadside stop.

An examiner may consider:

• whether the light colour is permitted
• whether the device resembles an emergency beacon
• whether the equipment distracts or confuses other road users
• whether mandatory lights remain visible
• whether the mounting creates a physical danger
• whether the device restricts the driver’s view
• whether wiring or installation appears unsafe

The outcome will depend on the defect and its severity.

It may involve advice, a defect record, prohibition or other enforcement action.

Our guide to preparing for a DVSA roadside inspection explains the wider records and vehicle checks operators should have ready.

Frequently asked questions

Are illuminated cyclist warning signs legal on HGVs?

They can be lawful when the device and installation meet the applicable requirements.

Where the sign operates with the indicators, DVSA says it may be treated as a direction indicator. Colour, flash rate, synchronisation and mounting must therefore be considered.

Can a VRU sign be mounted on a side guard?

DVSA advises that these devices should not be positioned on side guards or rear underrun devices.

A protruding device mounted in a dangerous position may lead to an annual test failure or roadside enforcement.

Are moving LED eyes legal in an HGV windscreen?

DVSA advises that any light showing moving images is almost certainly illegal. It also warns that decorative displays can distract or confuse other road users.

The safest approach is not to fit them to a road-going vehicle.

Can I use blue flashing lights while reversing?

Blue warning beacons are restricted to emergency and specifically authorised vehicles. DVSA says unauthorised blue lights fitted to HGVs should be removed.

Use compliant reversing safety equipment instead.

Is a light legal because it is sold as “road legal”?

Not automatically.

The operator remains responsible for ensuring that the product, installation and use comply with the applicable rules.

Will an illegal accessory always fail the MOT?

Not every technical problem produces the same outcome.

DVSA says some technical non-compliance involving VRU signs may receive an advisory, while equipment installed in a clearly dangerous way can result in failure.

Roadside enforcement may also differ from the annual test outcome.

Should aftermarket lights be included in PMI records?

Where equipment is fitted to the vehicle, it is sensible to include its condition, mounting, wiring and operation within the operator’s maintenance process.

Any fault or removal should be recorded.

Final takeaway

Aftermarket lights can appear to be a small modification.

But the wrong colour, flash rate, mounting position or display can turn a well-intentioned safety product into a compliance problem.

The safest rule is straightforward:

Do not fit first and ask questions later.

Confirm the product’s approval, intended use and installation requirements before it goes onto the vehicle. Record what has been fitted, brief drivers and include the equipment within normal inspections and defect reporting.

HauliK helps UK transport operators organise vehicle checks, defect reports, maintenance records and supporting evidence in one place.

It does not approve vehicle modifications or determine whether an accessory is legally compliant. Operators should check the latest DVSA guidance and obtain competent technical or legal advice where necessary.

This article provides general information for UK transport operators and is not legal, engineering or compliance advice. Rules and official guidance may change. Always check the latest GOV.UK, DVSA and legislation sources before fitting or using vehicle lighting equipment.