Research and analysis

Vehicle Market Surveillance Unit: results of the 2023 programme

Published 23 November 2023

Introduction

The Driver and Vehicle Standards Agency (DVSA) has a market surveillance unit, which inspects vehicles, trailers and equipment to make sure they meet safety and environmental standards.

This report sets out the findings of vehicle and component testing during 2023.

There’s a different report on the Vehicle Market Surveillance Unit’s 2023 emissions testing programme.

1. Aftermarket emissions components: product markings and advertising

Aim of the programme

We checked the compliance of catalytic converters (CATs) and diesel particulate filters (DPFs) supplied in the UK.

We looked at whether each component:

• was catalogued correctly
• had the right markings
• met the relevant type approval requirements
• was advertised correctly

What we did

We carried out broad market surveillance by:

• doing open-source online research
• attending relevant industry events
• conducting mystery shopper exercises across online and high street retailers

We used MOT emission failure data and broad market surveillance to check a sample of 85 different component numbers across 32 manufacturers (based inside and outside of the UK).

What we found

We found that none of the parts were incorrectly catalogued.

We also checked 15 suppliers to ensure that a member of the public would receive the correct Euro level component when bought, and that the parts bought were marked accordingly. All the parts supplied were marked according to the relevant regulations.

There were 11 instances of incorrect Euro level components being supplied. We reminded these suppliers of their obligations and provided them with education.

We spoke with the Berlin-based AutoDoc AG, the largest European aftermarket component supplier, regarding aftermarket CATs and DPFs for sale on their website under the brand name NTY. After these discussions, Autodoc made the decision to remove all NTY CATs and DPFs from their site regardless of their legality.

We test purchased 14 ‘sports catalytic converters’ designed for racing. This highlighted an area of the aftermarket industry that appeared to be non-compliant, with components not correctly advertised for off-road use only, or not being correctly marked as per the regulations.

Education and engagement with 22 suppliers and manufacturers of sports catalytic converters had a positive effect. They changed their advertising to make it clear that these types of components are not legal to be fitted to road vehicles and do not have type approval.

The work that DVSA has completed over the previous years, coupled with the engagement of manufacturers, cataloguers, trade associations, suppliers, distributors and online platform sellers, appears to have had a positive effect on the industry, with measured accuracy of seller information and compliance of components.

2. Aftermarket emissions components: testing

Aim of the programme

We checked the compliance surrounding emission components. This is in relation to aftermarket sales of catalytic converters (CATs) and diesel particulate filters (DPFs).

What we did

We identified and bought 3 used vehicles deemed to be either amongst the most common vehicles in terms of catalytic converter and diesel particulate filter aftermarket sales.

Volkswagen Polo 1.2 (petrol)

We identified 9 components for this vehicle. We obtained 5, and 4 were unobtainable.

They were:

• BM Catalysts BM91712H
• EEC (European Exhaust & Catalyst) VK6133T
• Walker 28058
• Bosal 090/805
• Vegaz SEK951 (relabelled Veneporte part)

Vauxhall Corsa 1.3 (diesel)

We identified 8 components for this vehicle. We obtained 4, and 4 were unobtainable.

They were:

• Cats & Pipes GMF196
• Walker 73043
• Bosal 097-575
• EuroFlo EPGM7028TA (relabelled AS part)

Nissan Qashqai 1.5 (diesel)

We identified 7 components for this vehicle. We obtained 3, and 4 were unobtainable.

They were:

• Cats & Pipes DNF123
• Walker 93078
• Euroflo EPDN7006TA (relabelled AS part)

Next steps

We’ll continue our market surveillance of aftermarket sales of catalytic converters (CATs) and diesel particulate filters (DPFs) into 2024 to ensure these components meet legislative emissions requirements.

Depending on the findings, we may need to take enforcement action against non-compliant retailers and manufacturers. Issues with other type approval authorities’ approvals will be reported to them and to the Commission.

3. Advanced driver assistance systems (ADAS)

Aim of the programme

We checked that advanced driver assistance systems (ADAS), specifically advanced emergency braking systems (AEBS), were functioning correctly. Our aim was to check how they function across the following 3 approval tests as required by UNECE regulation 131:

• warning and activation test with a moving target
• warning and activation test with a stationary target
• false reaction test

What we did

We tested the AEBS fitted to 5 vehicles with a gross weight of between 3501kg and 8000kg. The vehicles were:

• Mercedes Atego 816
• Isuzu Forward N75
• Ford Transit PSV
• Iveco Daily
• Mercedes Sprinter

We prepared the vehicles before testing. This included:

• a vehicle check to ensure each one was fit for test
• diagnostic scans to ensure AEB associated parameters had no fault codes present
• being loaded to a DVSA specified test weight

Of the 5 vehicles tested under this programme, the AEBS installed in 3 of the vehicles functioned as required across all 3 tests.

What we found

During the ‘warning and activation with a stationary target’ test, the AEBS on 2 of the vehicles did not activate as required under the regulations. The AEBS functioned as required on both vehicles during the other 2 tests.

Next steps

We’ll continue to test advanced driver assistance systems programmes during 2024. We will look to test larger vehicles (N2 and N3) in future test programmes.

4. Brake pads

Aim of the programme

We checked the supply of aftermarket brake pads in the UK to make sure that they:

• met the type approval requirements
• had relevant markings
• met safety standards

What we did

In previous years’ market surveillance work, we had identified that the brands Blueprint and National Brake Technology were supplying brake pads where some of the vehicles specified on the packaging were not listed on the approval certificate. They were therefore not approved to be fitted to those vehicles.

We followed up these non-compliances this year. When we made further test purchases, we found no errors with these brands. This confirms that the companies had brought the products back into compliance with the approval.

This year, we bought another 35 brake pads across a range of manufacturers and distributors to check that they complied with type approval.

What we found

We found that 3 of the 35 brake pads test purchased had some of the vehicles specified on the packaging not listed on the approval certificate. They were therefore not approved to be fitted to those vehicles.

All 3 companies (Brakefit, Stark Automotive GMBH, and Meyle AG) admitted an oversight in checking full approval documentation. They worked with the authorising type approval authority to extend their original approval.

Next steps

To ensure future compliance in the industry, we wrote letters to suppliers and manufacturers both based within the UK and based outside selling into the UK.

This programme will extend into 2024 with the addition of physical testing of category L brake linings across the UK.

5. Certificate of conformity

Aim of the programme

We checked that manufacturers and dealerships were supplying a paper certificate of conformity with each new vehicle to prove that it had been manufactured in conformity with type approval standards.

This year, we focused on:

• manufacturers and dealerships that we hadn’t looked at before
• revisiting manufacturers and dealerships that were identified in previous years as being non-compliant with the requirement of the regulation

What we did

The manufacturers we looked at across the range of programmes were:

• Audi
• BMW
• Citroen
• Ferrari
• Ford
• Hyundai
• Jaguar Land Rover
• Kia
• Lamborghini
• Lotus
• Mazda
• MG
• Maserati
• Mercedes-Benz
• Nissan
• Peugeot
• Renault
• Skoda
• Tesla
• Toyota
• Volkswagen

The manufacturers that we revisited from previous years to ensure non-compliance was resolved were:

• BMW/Mini
• DS
• Honda
• Peugeot
• Renault

The manufacturers visited for this year’s programme were:

• Fiat
• Porsche
• Volvo cars

BMW and Mini

Bayerische Motoren Werke AG, better known for their cars brands BMW and Mini, have been our principal focus for the dealerships revisited in Great Britain in 2022 and 2023.

These companies previously did not routinely supply a paper certificate of conformity with each new car.

The result of the engagement of DVSA with BMW and Mini was extremely positive. 5 subsequent revisits to their dealers have shown that the advice has been taken on board. All new BMW and Mini cars are now supplied with a paper copy of the certificate of conformity upon delivery to the dealership.

Vauxhall

We had previously found some inconsistent shortcomings were found within Vauxhall dealerships regarding issuing a customer with a copy of the certificate of conformity. In 2021, Groupe PSA and Fiat Chrysler Automobiles were merged to form Stellantis and Vauxhall is now one of 16 car brands owned by this company.

Since DVSA first contacted Stellantis about their concerns, the company has reviewed their procedure for issuing certificates of conformity for new Vauxhall cars. They have moved Vauxhall over to the same procedure as Citroen, DS and Peugeot. The task for printing the certificates is passed to a third-party printing company, and these are then forwarded by Stellantis, bypassing the dealers, to the customer directly together with a covering letter.

Honda

A concern was raised in a previous year about Honda’s non-compliance in this area. We had found that certificates of conformity were not being issued by Honda in Japan and in the UK unless they were specifically requested by the dealer.

We contacted Honda UK, and it appears to have been a misunderstanding of their legal obligation. We provided Honda UK with comprehensive advice on their legal obligations. They are now following their foreign counterparts’ process, and they will now be issuing a paper certificate of conformity for each vehicle upon its arrival in the UK.

Jaguar Land Rover

In 2020 we identified Jaguar Land Rover as being non-compliant with the requirements. Following our visits to 2 dealerships in 2020, Jaguar Land Rover sent out an email across the UK and Europe informing all dealerships that certificates of conformity will be included in every new vehicle as per the requirements of 2018/858.

Toyota

We visited Toyota in 2021 and confirmed that they had previously received a memo from Toyota GB saying that, as of 1 December 2021, all new Toyota vehicles would be supplied with a certificate of conformity upon delivery.

This programme will now be intelligence led only. DVSA welcomes intelligence about certificate of conformity compliance.

6. Electrically assisted pedal cycles (EAPCs)

Aim of the programme

We checked the supply of electrically assisted pedal cycles (EAPCs) in the UK to make sure that they’re either:

• compliant with the relevant regulations
• type approved to the required safety standards

What we did

We identified a total of 113 different retailers and manufacturers. We made a range of test purchases to see if they were compliant with regulations.

What we found

We found that 66 of the 113 suppliers were selling electric bicycles that did not comply with the EAPC regulations. Of these, 21 were present on online selling platforms.

We visited 11 retailers in Great Britain and 11 retailers in Northern Ireland as part of mystery shopper exercises. We found that 3 were selling non-compliant electric bicycles. We found that 2 were openly selling high-powered/high-speed electric bikes for use on public roads and cycle paths. These are being investigated further.

There have, so far, been 7 suppliers successfully prosecuted through court with guilty pleas and subsequent fines and criminal convictions, with many still ongoing.

The prosecuted suppliers are:

• Monsterebikes Ltd
• Hi-Fi Confidential Ltd (MATE Bike)
• Hawkwheels Ltd
• Gili Retail Ltd (Direct Electric Bikes)
• Webalee Ltd
• Edward Garstin (EzEbike)
• Cyclotricity Ltd

A conviction and total fine of £18,613 was handed to Gili Retail Ltd for supplying non-compliant bikes of high speeds and power.

Following these successful convictions, suppliers have been instructed to recall and remedy all non-compliant products they have supplied to customers. We are monitoring these recalls to ensure they are completed within a timely manner.

Next steps

We’ll continue this programme into 2024. We’ll work alongside other government agencies, industry bodies and trade associations to influence and educate suppliers and end users to ensure compliance.

We will also check the compliance of:

• 3-wheeled electric bikes and conversion kits
• services to convert standard pedal cycles into electric bikes

7. E-scooters

Aim of the programme

We carried out online open-source research and visited retailers, shows and events to investigate suppliers and manufacturers of electrically powered standing and seated scooters (e-scooters) in the UK. We checked whether they are being sold in line with legislative restrictions.

Retailers must provide their customers with accurate information about the legal restrictions on e-scooter use. Failure to do so is an offence.

What we did

We conducted broad market surveillance across the UK by:

• doing open-source online research
• attending relevant industry events
• conducting mystery shopper exercises across online and high street retailers

We identified 61 suppliers and checked their compliance against the regulations.

What we found

We found that 8 e-scooter suppliers were correctly advertising e-scooters for private land use only. These suppliers were:

• Argos
• Costco
• Currys
• Halfords
• Scootify Ltd
• The Electric Scooter Shop
• ProScooter
• Pure Electric

36 suppliers were advertising e-scooters for sale with a disclaimer present regarding riding on private land only. However, alongside the disclaimer, they were openly displaying images and videos depicting road or pavement use and riding in public places. These suppliers were also using words that referred to “commuting”, “city use”, “getting around town” and other suggestions of riding on roads and public places.

17 suppliers were advertising e-scooters for road use, riding on pavements and using in publicly accessible places, with no information on where privately owned e-scooters can be ridden.

We sent warning letters to the 53 non-compliant suppliers, reminding them of the current regulations around e-scooter use and advertising. These were sent in parallel with letters written by The Rt Hon Jesse Norman MP reminding retailers of their obligations.

Suppliers that continue to ignore regulations or have failed to engage with DVSA will be subject to further investigations.

A further 29 sellers were identified across online selling platforms, of which 3 were fully compliant with their advertising. The remaining 26 either had no legal information displayed for the customer or had misleading images and messages regarding the legal use of privately owned e-scooters. Action was taken in conjunction with the platforms and listings were either removed or updated accordingly.

Next steps

Although there is still a significant degree of non-compliant advertising of private e-scooters, the overall response to advice and information from DVSA has largely been positive. Most suppliers have made changes to their marketing.

We will continue with the broad market surveillance of the electric scooter market to ensure industry compliance.

We will also test certain e-scooters to determine their power and speed capabilities and any potential to comply with prospective future constructions and use requirements. We also expect to work with other enforcement agencies.

The 2024 programme will also include mini-petrol scooters that are subject to type approval regulations for road use.

8. Motorcycle exhaust systems and silencers

Aim of the programme

We checked aftermarket motorcycle exhaust systems and silencers on the market in the UK. We also tested a sample of aftermarket exhausts and silencers, both approved and non-approved, to assess compliance with noise approval standards.

What we did

We checked 34 manufacturers, distributors and retailers as potential suppliers of aftermarket motorcycle exhaust systems and silencers.

Of these:

• 14 were selling via their own website
• 6 were selling via eBay
• 4 were selling via Amazon
• 2 were selling at industry related events

We carried out 8 establishment visits:

• 4 in Northern Ireland
• 3 in Scotland
• 1 in England

What we found

Test purchases

We test purchased 24 different exhausts and silencers and checked for the required approval or relevant markings.

We found that 9 were approved.

The remaining 15 had no approval markings and were not marked “not for road use” or “pre-1985 MC only”. Of these, 5 were stamped with British Standards BSAU markings, but were of a type that required type approval.

Events

We attended a motorcycle event where a manufacturer was displaying multiple aftermarket silencers. We inspected 5 of these. We found that 1 had type approval markings, and 4 had no markings of any kind.

We attended a second event where a manufacturer was displaying 12 aftermarket silencers. We found that:

• none of them had type approval markings
• 1 had British Standards BSAU markings
• the remaining 11 had no markings and were not advertised as not for road use

We have contacted all non-compliant sellers and manufacturers identified from the broad market surveillance. We gave them warnings about bringing products into compliance and reminded them that enforcement action will be taken where they fail to do so.

Tests

We tested 9 aftermarket exhaust systems and silencers across 2 different types of motorcycle:

• 2019 Harley Davidson XL883N Euro 4
• 2018 Suzuki GSX-R1000 Euro 4

We chose these motorcycles as they are popular and common in the UK and there’s a wide range of aftermarket exhausts available for them.

The bikes were tested with the original exhaust (OEM) fitted to establish the baseline noise values.

We tested 4 aftermarket exhaust systems and silencers for the Harley Davidson. 2 were approved and 2 were non-approved products. A fifth approved system for this bike did not fit the motorcycle and therefore was not tested.

We tested 5 aftermarket silencers for the Suzuki. 3 were approved and 2 were non-approved products.

Of the 4 exhaust systems/silencers tested for the Harley Davidson, the results were:

• 1 pass (approved product)
• 1 fail (approved product)
• 2 fails (non-approved products)

Of the 5 exhaust systems/silencers tested for the Suzuki, the results were:

• 3 fails (approved products)
• 2 fails (non-approved products)

Next steps

Where the components were found to have failed in the noise testing, we have given manufacturers the opportunity to explain the results and describe the conformity of production strategies they used.

We have informed the approval authorities of the results.

At the time of writing this report, the type approval authority is working with the manufacturer of the approved Harley Davidson product regarding their testing and conformity of production. We’re working with the approval authorities and the manufacturers of the 3 approved systems for the Suzuki to find out why the failures happened and to bring the products into compliance.

We’ll continue testing and market surveillance into 2024, and we’ll consider enforcement action against manufacturers who do not comply persistently.

9. Motorcycle helmets and visors compliance

Aim of the programme

We checked the sale of motorcycle helmets and eye protection (visors and goggles) in the UK to ensure that they:

• meet the type approval requirements
• have the right markings
• meet safety standards

What we did

We identified a total of 65 different retailers and manufacturers. We made a range of test purchases and visual checks of helmets and visors to establish compliance with regulations.

We inspected:

• 66 helmets
• 39 visors
• 8 sets of goggles

What we found

Visors

We found that 13 visors had no indelible approval markings. Easy-peel stickers had been used to display the approval number on 5 of those visors. We contacted the manufacturers, retailers and online selling platforms to have the products either removed from sale or brought into compliance. Three manufacturers responded positively to say that they would alter their visor stickers to non-peel for all new products entering the market.

We inspected 12 dark tinted or mirrored visors and found that they had no approval markings. We advised the manufacturers and retailers about the findings and their obligations. We reminded them that products should not be placed on the market without the relevant approval and usage information for customers, and that products must be removed from sale and brought into compliance.

Goggles

We found that 5 out of 8 sets of goggles had no approval markings. They were made of fragile plastic that would shatter on impact and offer no protection in the event of an accident. We reported them to selling platforms, and the listings were removed.

Helmets

Two of the helmets that we test purchased displayed approval markings. However, when we checked with the approval authority, we found that the approval had been withdrawn and therefore the helmets should not still be available on the market. We advised the retailers, and the affected products have since been removed from sale.

“Vintage” or “retro” style helmets have proved to be the biggest area of non-compliance, but the problem also exists with full-face, flip-front, and open-face helmets. 145 listings for a particular vintage style helmet were removed in one sweep of one platform.

Next steps

We’ll continue this programme into 2024 with a package of testing of motorcycle helmets and visors.

10. Non-road mobile machinery (NRMM)

Aim of the programme

We checked the supply of new non-road mobile machinery (NRMM) for sale in the UK to ensure that the engines:

• met the type-approval requirements
• have the relevant approval markings

What we did

We carried out open-source research of 43 UK-based online suppliers of NRMM. We sent requests for type approval information to 21 of these suppliers.

We found that only one of the establishments was selling NRMM products fitted with a non-type approved engine. We engaged with the seller and advised them on the requirements and their legal obligations. The distributor subsequently removed the entire brand of products from sale.

We carried out 4 covert establishment visits as part of our market surveillance work in Northern Ireland. We also attended 4 industry exhibitions across the UK.

Across the year, we bought 32 NRMM products from online platforms. We found that 23 of these did not have relevant type approval markings. We contacted the online platforms and the products were removed from sale.

We have found smaller NRMM products available on the UK market, manufactured and supplied by manufacturers based outside of the UK and EU, without the required type approval. These have been removed from the market.

Next steps

Our work in 2024 will be shaped by the ongoing concern regarding smaller NRMM products available on the UK market through online platforms. We’ll do further research online and continue to make test purchases.

We’ll also include agricultural forestry machines and check type-approval certification for machines placed on the UK market through distributors and online selling platforms.

11. Part-worn tyres

Aim of the programme

We checked whether dealers were selling part worn tyres that did not comply with the regulations.

If part-worn tyre dealers consistently ignore the regulations, selling tyres that have not been tested under inflation or thoroughly inspected for damage, it can pose a risk to public safety.

What we did

We carried out mystery shopper exercises in 7 areas of the UK. Local trading standards officers accompanied 6 of these exercises. We visited 115 premises in total.

What we found

We bought 79 part-worn tyres during the mystery shopper exercises. An engineer inspected them and found 7 of them to be unroadworthy because:

• 3 had objects piercing the tyre
• 1 had a deep cut to the cords
• 1 sidewall was perished and fit incorrectly to the rim
• 1 had bulge in the sidewall
• 1 had a string plug repair

Only 16 of the 79 tyres were marked ‘part worn’.

Trading Standards are following up on these non-compliances where necessary. One garage (Fit & Go Tyres, at 2 St James Road, Watford) was convicted on Wednesday 1 March 2023 at St Albans Magistrates Court of supplying a part-worn tyre that was unsafe and not marked as being part-worn.

We bought 28 tyres advertised as being part-worn from online suppliers.

Of the 28 tyres we bought online, 3 were deemed to be non-compliant with the regulations because:

• 1 had a metal staple penetrating through the tyre
• 1 had a cut in the secondary tread area which was deep enough to reach the cords
• 1 had a tread depth of less than the minimum 2mm requirement to be sold as a part-worn tyre

Only 3 of the 28 tyres were marked ‘part worn’.

We sent a letter to the sellers of non-compliant tyres to remind them about their obligations.

Tyre age

The Tyre Safety Regulations do not stipulate a maximum tyre age, but we noted the number of tyres bought with date stamps indicating the tyre was more than 10 years old.

Of the tyres bought in person, 15 were over 10 years old. The oldest had a manufacturer’s mark of week 38 of 2003 (over 19 years old).

Of the 28 tyres bought online, 6 were over 10 years old. The oldest had a manufacturer’s mark of week 10 of 2009 (over 13 years old).

DVSA published an article for the ‘Moving on’ blog and shared a message to taxi and private hire operators through local authorities on what to look out for when purchasing part-worn tyres.

Next steps

We’ll continue this work into 2024, with further mystery shopper visits alongside Trading Standards to different areas of the UK.

12. Small trailers

Aim of the programme

We checked suppliers selling small trailers in the UK to make sure that they:

• meet the type approval requirements
• have relevant markings
• meet safety standards

What we did

We carried out broad market surveillance through open-source research to identify businesses and individuals who supply small trailers.

We wrote to 91 small trailer suppliers (77 in Great Britain and 14 in Northern Ireland) as part of a desk-based assessment. We asked them to provide their approval documentation and details of the trailers they supplied.

What we found

Our investigation revealed that David Murphy Towing Brackets Ltd, a Northern Ireland based trailer manufacturer, had knowingly supplied 503 trailers illegally for road use for over 7 years. They had failed to make records for supplying them since October 2014.

This information was discovered following a routine request to suppliers in Northern Ireland for pertinent information.

They were successfully convicted by DVSA for the supply of non-type approved trailers.

We also identified that Neville Porter Trailers, also from Northern Ireland, was supplying small trailers without type approval. They supplied a total of 84 small trailers without type approval between March 2020 and July 2022.

Both cases were referred for prosecution at Belfast Magistrates court. The defendants pleaded guilty to all the charges and they were fined a total £13,150. In court, the companies were told to recall all trailers supplied without approval and bring them into compliance.

A total of 7 trailer suppliers were identified for test purchasing to check compliance with road safety requirements and the regulations. We found that 4 of the trailers had no noted issues, and 3 of the trailers had minor issues. We spoke to the relevant manufacturers to explore the reasons for the noted issues, and to mitigate any future non-compliance.

Next steps

We’ll continue our broad and risk-based surveillance of suppliers of small trailers into 2024.

We have built strong relationships with the trailer industry. We’ll continue to work closely with the National Towing and Trailers Association (NTTA) in reaching out to the industry to advise and educate through presentations and guidance in ensuring the industry is compliant.

13. Tyre labelling

Aim of the programme

We checked the supply of new car, van and truck tyres in the UK, to ensure that suppliers are fulfilling their obligations as set out in the relevant tyre labelling regulations and that tyre manufacturers are assigning appropriate performance values to their tyres.

What we did

We visited 103 different tyre suppliers across the UK.

What we found

Of the 48 tyre suppliers visited in Great Britain, 24 did not provide the tyre label information as required.

Of the 55 premises visited in Northern Ireland, 15 failed to fulfil their obligations regarding provision of tyre label information.

We contacted 37 suppliers to advise and remind them of their obligations.
We issued 2 with a civil penalty compliance notice to bring their practices into conformity with the regulations.

Wet grip performance

Of the 20 different tyres tested for wet grip performance, 9 tyres performed at a lower rating than rated on the tyre label.

Fuel efficiency performance

Of the 20 different tyres tested for fuel efficiency performance, 1 tyre performed at a lower rating rated on the tyre label. 4 tyres performed better than rated on the tyre label.

Noise levels

Of the 20 tyres tested for their noise levels, 4 were found to be louder than the value declared by the manufacturer. One tyre performed better than rated on the tyre label.

None of the tyres failed to meet all 3 declared values on the label, but 3 tyres failed to meet 2 of the values specified on the tyre labels.

Next steps

We will follow up these results with the tyre manufacturers to ensure that the tyre labelling is accurate.

We’ll continue this work into 2024. We will test different sizes and brands of tyres against the tyre label parameters to check for their accuracy.

14. Vehicle alterations (pop and bang noise)

Aim of the programme

Some garages openly offer services to alter the noise emissions of vehicles through:

• catalytic converter removal

• engine management reprogramming

• noise emissions alterations

We checked compliance surrounding these vehicle alterations.

What we did

We carried out mystery shopper exercises to investigate the noise alteration services being offered.

We used 3 different petrol vehicles. They were:

• a Honda Civic
• a Volkswagen Polo
• a Ford Fiesta

We baseline tested the cars in controlled laboratories before the alteration to make sure they met the relevant approved noise standards. We also tested them after the alteration.

What we found

Honda Civic

The Honda Civic only had an ECU (engine control unit) software alteration. The OEM catalytic converter was not removed or tampered with.

Our baseline testing found the vehicle to be above the permitted sound limits before modification. However, the baseline testing was conducted in cold conditions. This is likely to cause an increased noise measurement compared to that of warmer testing. The testing after the modification took place in temperatures 6 °C above the baseline ambient, so it’s likely to minimise any increased noise emissions caused by vehicle modifications.

The baseline noise measurements were considered inconclusive. We were therefore unable to determine a definitive noise increase.

Volkswagen Polo

The Volkswagen Polo had engine ECU software and exhaust modifications. The noise test results before modification (baseline) were:

• drive-by result: 75dB (limit: 75dB)
• static result: 73dB (limit: 79dB)

After the car was modified, the noise test results were:

• drive-by result: 75dB (comparison: +0dB / limit: 75dB)
• static result: 84dB (comparison: +11dB / limit: 79dB)

It passed both the static baseline and post modification noise measurement tests. It failed the post modified static noise test.

Ford Fiesta

The Ford Fiesta had:

• an engine ECU software alteration
• a revised intake system fitted
• exhaust alterations

The post modified drive-by noise measurement increased by 2dB to 77dB. This exceeded the 75dB limit.

Next steps

Our investigations into the garages are still taking place at the time of writing this report. The outcomes of the investigations will be available once we’ve completed them.

We will continue to investigate defective or unsuitable vehicle parts being supplied during 2024.