Top image: A look down Avenue Champs Élysées as seen from the Arc de Triomphe.
As more information about the health impact of road noise becomes available, it is clear that EU-wide measures are necessary to minimize the negative consequences on public health. The fact is there are more cars on the road and European roads are becoming noisier. According to the World Bank, in the EU in 2011 there were 552.5 vehicles on the road per 1000 people, compared to 513.2 per 1000 inhabitants in 2005. Today, the EU considers the impact on health from road noise as second only to that from poor air quality.
How does noise affect health?
Noise from traffic affects people’s health both directly and indirectly. It affects our nervous and hormonal system, which can increase the risk of cardiovascular disease and damage cognitive function. Health problems include sleep disturbance, tinnitus, heart disease, and raised blood pressure, as well as disrupted learning and memory (especially in children).
In 2011, the WHO’s Global Burden of Disease report estimated that each year Europeans lose at least one million healthy life years due to disability or disease caused by traffic noise – and this is considered to be an underestimate of the real total.
Quantifying the problem
In 2002, the Environmental Noise Directive 2002/49/EC (END), a major step forward in identifying and quantifying environmental noise pollution in the EU, was ratified. The aims of END include:
- Monitoring the environmental problem
- Informing and consulting the public
- Addressing local noise issues
- Developing a long-term EU strategy
This EU directive is implemented in each EU country, with every Member State defining action plans. To assess road noise, all countries must prepare strategic noise maps for major roads using harmonised noise indicators: Lden (day-evening-night equivalent level) and Lnight (night equivalent level). Based on these noise maps, local entities are responsible for preparing action plans to reduce road noise and to set targets together with the community.
For example, in Denmark, the Danish Road Directorate (Vejdirektoratet) responsible for all state-owned roads has prepared noise maps of the entire national road network – approximately 3800km in total, identifying housing areas that are particularly badly affected by road noise.
EU legislation to limit noise
Stricter vehicle noise standards encourage manufacturers
to produce noticeably quieter vehicles. The European Commission currently has several new vehicle noise emission requirements including:
- Motor vehicle noise: Directive 540/2014
- UN-ECE Regulation 51 including new ASEP regulations to ensure the relevance of compliance
- Tyre noise standards: Regulation 661/2009 (2012)
- Tyre labelling: Regulation 1222/2009 (2012)
- A range of additional requirements for other vehicle types, such as motorcycles
Noise legislation and standards
Legislation is used to manage road noise by placing limits on noise sources, potentially affecting hundreds of industries. Legislation refers to standards to define how to determine noise emission (noise coming from different sources) and immission (noise at receiver points, for example, houses):
- Legislation defines what is allowed (for example, by placing limits on noise sources).
- Standards are the agreed methods for determining road noise emission in total and from different sources, and for determining noise levels in the environment at receiver points.
By following agreed standards, global manufacturers can better understand which way legislation will go and be ready for new requirements. The standards for noise levels help to ease communication and ensure that all stakeholders agree on a common methodology to measure noise and to isolate the various sources of noise (normalizing other factors). Overall road noise is a mixture of several factors, for example:
- Infrastructure (noise barriers, speed limits, etc.)
- Tyre type
- Asphalt type
- Vehicle type (car, truck, motorbike, van, etc.)
- Operational conditions due to the driver (such as acceleration, braking and revving) or due to the weather conditions (for example, if roads are wet)
"Brüel & Kjær staff around the world review proposals and influence their development through ISO Working Groups."
Limits to tackle traffic noise
Different limits are placed on different types of vehicles and on tyres. For several years, the European Commission, in cooperation with stakeholders such as the European Automobile Manufacturer’s Association (ACEA), has had a range of such regulations.
In 2014, the European Commission adopted stricter noise emission standards to encourage vehicle manufacturers to produce noticeably quieter vehicles. The subsequent legislation means that noise limit values will be tightened by an additional 3 to 4 dB(A) from 2016 to 2026 for passenger cars, vans, buses, coaches and trucks. New limits will be phased in by July 2016, 2022 and 2026 and the EU estimates that these measures will reduce vehicle noise by 25%.
The EU also recommended legislation to tighten the rules regarding tyre noise and a labelling system was agreed to inform consumers about the best and worst performers. The labels have been on all tyres for sale in Europe since 2012. This has the potential to be an important contribution to noise reduction because, above speeds of 30 – 50 km/h, tyre noise/road is the most significant source of noise.
Line diagram showing the sources on the truck delivering the highest sound pressure levels at a given position on the test track..
ISO Sound Pressure Level vs position compared with SPL of source highlighted in upper graph. In this example the highlighted source delivers highest SPL of all sources at –6 m
Action across Europe
The challenges of road noise are being tackled in different ways across Europe. For example, on one of the busiest ring roads around Paris, four action plans have been proposed to reduce noise levels: a reduction of speed from 80 to 70 km/h; encouraging night-time drivers to reduce their speed to 50 km/h; using low-noise road surfaces; and an increase in the number of noise barriers.
In the UK, for example, the Noise Abatement Society is promoting quieter goods delivery vehicles. This was a topic at the 2014 ‘Quiet Cities’ global summit, where DHL launched a ‘city safe, city quiet’ gas-powered concept vehicle. In order to reduce noise levels, the truck has been specifically designed with nylon components, pneumatic technologies, and a tail-lift running on a motor operating between 60 and 65 dB(A). Furthermore, a directional, tonal alarm – which allows noise outside the hazard zone to dissipate quickly – has been fitted.
Another example is ‘NordTyre’, a joint project between the Nordic countries that plans to investigate the connection between noise from car tyres and typical Nordic road surfaces, with the goal of better understanding how tyres with a low noise level contribute to combatting noise problems, and how this contribution can be optimized.
Tougher noise limits to come?
What is consistent across Europe is the need to meet new EU standards and to keep up to date with future legislation. In addition to noise emission limits getting stricter, work is ongoing to investigate and manage noise specifically from tyres and from asphalt.
The automotive industry and others are continually developing solutions to meet market demands, fulfil test codes and their limits, and provide documentation and labelling in accordance with standards and legislation. Engineers in many fields share a common interest in noise pollution reduction and will continue to design new technologies that produce less noise.
Working together with manufacturers
Where will the focus of noise-limit legislation be in a few years? Perhaps there will be more attention on road surfaces rather than tyre or engine noise, since this has been demonstrated to have a big impact on noise levels. All stakeholders must continue to agree on how to measure noise and find ways to reduce levels efficiently, without reducing quality of life. Companies such as Brüel & Kjær can contribute to greater accuracy, helping manufacturers to better meet limits and comply with future legislation. Brüel & Kjær is also heavily involved in discussing and developing future standards – gaining the insight that is vital to be able to advise customers and develop effective solutions that help efficiently meet noise limits in the future.
Assessing road noise levels
Researchers assess noise levels at different intervals. END defines two indicators:
- Lden – the average noise levels over all days,
evenings and nights in a year
- Lnight – the average yearly night time noise level
(nights having a minimum duration of eight hours)
Brüel & Kjær’s involvement with legislation and standards
To be ready to supply optimal solutions and support at the right time, Brüel & Kjær monitors legislation and any proposed new developments. Since legislation typically refers to standards that cover the assessment methodology, Brüel & Kjær is deeply involved in standardization and maintains a good network with leading researchers and practitioners.
Brüel & Kjær staff around the world review proposals and influence their development through ISO Working Groups. In addition, Brüel & Kjær participates in ISO Acoustics (TC43) Plenary Meetings, which formally approve resolutions regarding standardization and manage assessment standards. The Brüel & Kjær corporate ISO Standardization Coordinator, Douglas Manvell, is on the ISO TC43 Advisory Panel, which advises on policy. ISO TC43 (acoustics) has 17 active working groups developing 43 standards and typically publishes between 15 – 30 formal documents (standards in various stages of development) for review each year.
One example of how Brüel & Kjær standardization work is organized is the proposed new tone identification method for use in all ISO standards – from environmental noise to noise from computers and office equipment. Here, a 9-man strong Brüel & Kjær task force, representing Product Management and R&D, ensures that the standard is reviewed, understood and assessed technically and commercially for implementation in solutions in the future.