Loud vehicles

Individual vehicles cause disruptive noise peaks that stand out from usual road noise. This disturbance can usually be avoided if drivers change their driving style and do not modify their vehicles in ways that increase noise.

One reason for excessive noise peaks in road traffic is driving style. Another is noise-boosting modifications to vehicles. Motorcycles and souped-up cars cause a particularly large number of complaints, but a considerate driving style and low engine speeds can prevent a great deal of unnecessary noise. This is especially important at night.

Avoidable nuisance

As set out in the Road Traffic Act (RTA) and the Traffic Regulations Ordinance (TRegO), drivers must not cause any avoidable noise nuisance. Some examples of prohibited noise include high engine speeds when idling or when driving in a low gear, popping sounds from the exhaust system, and the noise caused by accelerating too quickly when moving off or repeatedly driving around without good reason in built-up areas (Art. 42 RTA, Art. 33 TRegO). The cantonal enforcement authorities are responsible for enforcing these provisions.

Excessively loud vehicles

Vehicles must comply with noise limit values in order to be approved for use on public roads. Limit values and test procedures are set out in the Ordinance on the Technical Requirements for Road Vehicles (RVTRO). This Ordinance is based on regulations that apply throughout the EU and also in Switzerland owing to its bilateral agreements with the EU. According to current regulations, the approval test does not permit devices that are not in normal use on the roads. This means it is prohibited to fit vehicles with noise-optimised devices for the purposes of the approval test. For example, noise-boosting exhaust flaps must be configured in the same way as they will be later on the roads.

In addition to adhering to the limit values, vehicles may not generate noise that exceeds the technically avoidable levels set out in the RVTRO. Unnecessary noise-boosting modifications are generally prohibited. There are also noise regulations for add-on parts such as converted exhausts. For instance, replacement silencers must be authorised and be just as effective as the originally approved models (Art. 53 RVTRO). Vehicles are checked for compliance with the regulations during the periodic roadworthiness inspection.

Information on relevant legislation

Further information and FAQs can be found on the Federal Roads Office (FEDRO) website on noise regulations for cars and motorcycles:

ASTRA: Lärmvorschriften für Personenwagen und Motorräder

Noise indicators

As driving style plays a significant role in noise emissions, it is important to provide drivers with information and make them aware of this issue. Noise indicators are one way of doing so. These work in a similar way to speed indicators – a display installed next to the road shows information about the noise produced by passing vehicles.

Lärmdisplay – Lärmwirkung Metaanalyse 2022 (PDF, 32 MB, 20.09.2022)Im Auftrag des BAFU