Guernsey’s proposal to criminalise altered exhausts that “intentionally increase noise” might sound like a straightforward solution to nuisance vehicles — but it risks becoming an arbitrary, unenforceable, and ultimately counterproductive policy. What Guernsey needs isn’t a blanket ban, but a measurable, fair and practical framework rooted in objective decibel (dB) testing, aligned with World Health Organization (WHO) guidelines.
The Problem With Blanket Bans
A blanket ban on non-standard exhausts assumes that all modifications are harmful — which is simply untrue. As local vehicle specialist James Larbalestier pointed out in the Guernsey Press (8 April 2025)1, classic and custom vehicles often rely on bespoke exhausts due to unavailability of OEM parts. Some modifications improve efficiency or are essential for maintaining older vehicles that are otherwise roadworthy.
Banning by default penalises owners not for their vehicle’s noise output, but for its appearance or configuration. This is neither fair nor enforceable. It risks alienating car enthusiasts and classic vehicle owners, many of whom contribute positively to the island’s economy and cultural fabric through restoration, tourism, events, and local trade.
The Case for Measurement
Noise is a measurable physical quantity, and regulating it should be based on what people actually hear, not how a vehicle looks. The WHO recommends:
- Maximum daytime noise exposure of 55 dB(A) to avoid significant annoyance.
- Night-time exposure of no more than 40 dB(A) to protect sleep and wellbeing.
These thresholds are widely recognised and scientifically grounded. They’re already used for railways, aircraft, construction, and industry — and should be applied to vehicles.
Portable dB meters are affordable, accurate, and used globally by police forces and regulatory bodies. Testing involves measuring sound pressure at a standardised distance (usually 0.5 to 1 metre from the tailpipe) and engine RPM, providing objective, repeatable data.
Practical, Fair, and Enforceable
Using dB-based testing allows Guernsey authorities to:
- Target real offenders instead of relying on subjective judgment.
- Avoid penalising quiet but modified vehicles.
- Enforce consistently, reducing ambiguity and potential legal disputes.
It also aligns Guernsey with international best practice.
The Cost of Noise
Excessive environmental noise isn’t just an annoyance — it’s a public health issue with real financial consequences. According to the WHO2 and EU3, chronic exposure to high noise levels contributes to cardiovascular disease, sleep disturbance, cognitive impairment, and stress-related illnesses. These effects increase healthcare costs, reduce workplace productivity, and diminish overall quality of life. For a small jurisdiction like Guernsey, the knock-on costs of ignoring vehicle noise — from lost sleep to reduced property values in noisy areas — can be significant. Investing in a targeted, evidence-based noise policy is a proactive way to reduce long-term societal costs; anyone living next to roads like the Grange in St. Peter Port will know how sleepless life can become.
Furthermore, noise abatement measures are highly cost-effective. A 2021 European Commission study showed that for roads there is a return of €10 in social benefits for every €1 spent on a specific noise measure 4
A practical, evidence-led noise testing policy could provide economic and administrative benefits:
- Boost to local automotive businesses: Custom builders and restorers could continue to operate legally, generating employment and tax revenue through workshops, parts suppliers, and specialist services.
- Reduced enforcement cost: Objective testing reduces the burden on police officers and court systems by cutting down on contested fines or ambiguous charges.
- Increased public trust: Fair, measurable rules increase compliance and legitimacy of local government, reassuring both residents and visiting motorists.
Moreover, this approach could underpin classic car shows etc. while upholding clear and enforceable noise standards.
Conclusion: Sound Policy Starts With Sound Measurement
Guernsey has a right and a need to address public noise emission, but it must do so rationally and fairly. Rather than banning modified exhausts outright, the island should introduce a clear noise limit, grounded in WHO guidelines and enforced through measurable dB testing.
This way, it targets the problem — excessive noise — not people with non-standard but otherwise legal and quiet vehicles. It ensures consistency, protects livelihoods, supports the local economy, and upholds the principle that laws should be based on evidence, not assumption.
A measured approach isn’t just good policy — it’s sound policy!
- https://guernseypress.com/news/2025/04/08/blanket-ban-on-altered-exhausts-unfair-says-local-vehicle-specialist [↩]
- https://www.who.int/europe/publications/i/item/9789289053563 [↩]
- https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=COM:2023:139:FIN [↩]
- https://op.europa.eu/en/publication-detail/-/publication/f4cd7465-a95d-11eb-9585-01aa75ed71a1/language-en pg 153, fig 5.23 [↩]