Reducing Vehicle Noise Pollution: Strategies For Quieter Roads

Noise pollution is a major hazard that impacts the quality of life for people and wildlife around the world. Vehicular noise pollution, caused by road, rail, and air traffic, is the second leading cause of negative health in western Europe, according to the World Health Organization (WHO). As cities continue to expand and traffic volumes grow, managing the environmental and health impacts of road noise has become a critical concern. To address this issue, various strategies have been implemented, including vehicular noise limits and their regulation, physical health check-ups for vehicles, and different operating times for noisy traffic. In addition, the use of electric vehicles (EVs) is also being explored as a way to reduce noise pollution, as they are significantly quieter than internal combustion engine (ICE) vehicles.

Opt for quieter vehicles, such as electric cars

Electric vehicles (EVs) are a fantastic way to reduce noise pollution. They are powered by electric motors rather than engines, making them much quieter than their internal combustion engine (ICE) equivalents. The only sounds they produce are from the tyres on the road and wind resistance. This makes them naturally lower than the legal noise limit for vehicles, which is currently 72 decibels but will be reduced to around 68 decibels by 2026.

The silence of electric cars benefits not only drivers and passengers but also pedestrians, cyclists, and residents of urban areas. This makes them an excellent choice for reducing noise pollution, especially in larger cities.

In addition to being quieter, electric cars are also better for the environment and cheaper to run and maintain than ICE cars. This makes them an attractive option for those looking to reduce their impact on the environment and their wallets.

While the quietness of electric cars is beneficial for reducing noise pollution, there are some safety concerns. As a result, electric cars are required by law to emit a sound of at least 56 decibels. This artificial engine sound is designed to alert pedestrians and increase with speed, providing an audible alert without causing noise pollution.

Overall, opting for quieter vehicles such as electric cars is a great way to reduce noise pollution caused by vehicles while also enjoying the benefits of a more environmentally friendly and cost-effective mode of transportation.

Improve road surfaces

Improving road surfaces is an effective way to reduce noise pollution caused by vehicles. Here are some strategies to achieve this:

Use of Low-Noise Road Surfaces

Low-noise road surfaces (LNRS) are designed to reduce traffic noise and are commonly used in noise-sensitive areas. Porous asphaltic concrete and cement-bound porous concrete are examples of LNRS that can absorb sound energy and reduce noise when tyres roll over them. The durability and persistence of these surfaces are essential to maintain their noise-reducing properties over time.

Regular Maintenance and Repair

Regular maintenance of road surfaces is crucial to minimise noise pollution. This includes monitoring and addressing the deterioration of road surfaces and tyre rubber hardness, which can impact noise levels. For example, the micro-texture of road surfaces can cause mechanical wear on tyre rubber, leading to reduced tread depth and increased noise. Therefore, regular maintenance to preserve the quality of road surfaces and tyres is essential.

Implementation of Rubberised Asphalt

Rubberised asphalt, or asphalt mixed with rubber from end-of-life tyres, has been found to reduce car noise by 4-5 decibels. This is achieved by reducing the stiffness of the asphalt, which in turn decreases tyre vibration and noise. Additionally, rubberised asphalt can extend the life of roads and lower maintenance costs, providing a more sustainable and cost-effective solution.

Acoustic Walls and Barriers

The use of acoustic walls and barriers can effectively reduce noise pollution from roads and railways. These structures are designed to bend and redirect sound waves away from nearby homes or populated areas. For example, the Dutch company 4Silence BV has developed walls with grooves of varying depths that reduce horizontal noise by redirecting it vertically. These walls are more effective in reducing noise than traditional concrete walls and require smaller barriers, making them a more efficient and cost-effective solution.

Implement noise barriers

Noise barriers are solid obstructions built between highways and the homes that line them. They are designed to reduce overall noise levels, typically by 5 to 10 decibels, cutting the loudness of traffic noise by half.

Design and Construction

Noise barriers can be built using a variety of materials, including earth, concrete, masonry, wood, metal, and other materials. The choice of material depends on factors such as aesthetics, durability, maintenance, cost, and public opinion. Regardless of the material used, noise barriers must be tall and long with no openings. They should also be designed to be visually appealing and preserve the surrounding area's aesthetic and scenic values.

Effectiveness

Noise barriers are most effective within 61 meters (200 feet) of a highway, usually benefiting the first row of homes. They must be tall enough to block the view of the highway from the receiver (the area that is to be protected from noise). To achieve a 5 dB noise level reduction, a noise barrier must be tall enough to break the line of sight from the highway to the receiver. After breaking the line of sight, a noise barrier can achieve an additional 1.5 dB of noise level reduction for each meter of barrier height.

To reduce noise coming around its ends, a noise barrier should be at least eight times longer than the distance from the receiver to the barrier. Openings in noise barriers for driveways or intersecting streets will destroy their effectiveness.

Public Reaction

Overall, the public reaction to highway noise barriers appears to be positive. Residents adjacent to barriers report improved sleep, easier conversations, and increased use of their yards in the summer. Negative reactions include restricted views, a feeling of confinement, and a loss of sunlight and lighting. Motorists have also complained of restricted views and a feeling of being "walled in."

Use acoustic monitoring to identify noise hotspots

Acoustic monitoring is a powerful tool for identifying noise hotspots and implementing effective noise reduction strategies. By employing advanced technology, such as the Sorama L642 Acoustic Monitor, authorities can visualise sound in real time and pinpoint specific locations where noise levels exceed acceptable thresholds. This technology aids in detecting faulty vehicles, monitoring road surface conditions, and creating detailed noise maps to guide urban planning and noise reduction initiatives.

Acoustic monitoring offers a data-driven approach to reducing noise pollution by providing accurate, real-time information on noise sources. With acoustic cameras and monitors, cities can continuously track noise levels at busy intersections, highways, or other noisy hotspots. This enables authorities to identify specific locations, such as roads with poor conditions or areas with speeding vehicles, that consistently produce excessive noise. By understanding the sources and patterns of noise, cities can implement targeted solutions, such as road modifications or the installation of sound barriers.

One example of the successful implementation of acoustic monitoring is the City of Newport in Rhode Island, USA. Newport utilised a mobile acoustic monitoring solution that could be moved between different noisy traffic hotspots, particularly during the crowded summer months. This strategy helped raise awareness and enforce regulations against intentionally loud vehicles, contributing to a quieter and more livable urban environment.

Acoustic monitoring also plays a crucial role in detecting faulty vehicles that contribute to excessive noise. Vehicles with faulty exhaust systems or tires can generate extremely loud noises, disturbing residents and causing various health issues. With acoustic monitoring technology, such as the Sorama L642 Acoustic Monitor, authorities can quickly identify these problematic vehicles and take appropriate action. This may include issuing noise violation tickets or recommending vehicle maintenance to reduce noise emissions.

In addition to identifying faulty vehicles, acoustic monitoring is valuable for monitoring road surface conditions. Poor road conditions, such as worn-out asphalt or uneven surfaces, can significantly contribute to noise pollution. Acoustic sensors strategically placed along major roads can detect unusual noise patterns, indicating that a particular stretch of road may require resurfacing or repair. By addressing these issues, cities can reduce overall noise levels and create smoother, quieter roads.

Furthermore, acoustic monitoring enables the creation of detailed noise maps. These maps visualise noise distribution across different areas, helping urban planners and local governments make informed decisions. By understanding how noise travels and accumulates in specific locations, authorities can strategically implement noise reduction interventions. For example, noise maps can guide the placement of sound barriers, the development of green spaces, or the modification of road designs to minimise noise pollution in residential and commercial areas.

By utilising acoustic monitoring technology, cities can take a proactive approach to reducing noise pollution caused by vehicles. This technology empowers authorities with actionable data to identify noise hotspots, address faulty vehicles, improve road conditions, and design quieter urban environments. As a result, communities can benefit from reduced noise levels, improved livability, and enhanced health and well-being for residents.

Choose fuel-efficient vehicles

Choosing fuel-efficient vehicles is an effective way to reduce noise pollution caused by transport. Electric vehicles (EVs) are a great choice for people who want to reduce noise pollution and carbon emissions.

EVs are powered by an electric motor, not an engine, so they are much quieter than their internal combustion engine (ICE) equivalents. The only sounds they make are from the tyres on the road and wind resistance. This means that EVs are naturally quieter than the legal limit for vehicle noise, which is currently 72 decibels but will be reduced to around 68 decibels by 2026.

The positive impact of EVs on noise pollution is particularly noticeable in larger cities, where noise pollution is most strongly felt. Research by the UK Health Security Agency (UKHSA) found that 40% of the UK population, or roughly 26.8 million people, are exposed to harmful levels of noise pollution caused by traffic. As well as causing hearing loss and tinnitus, noise pollution can lead to migraines, anxiety, depression, insomnia, high blood pressure, heart disease, and strokes.

In addition to being quieter, EVs are also better for the environment and cheaper to run and maintain than ICE cars. They can also help improve air quality by reducing carbon emissions.

However, the quietness of EVs can pose a safety risk to pedestrians, so legislation requires EVs to emit a sound of at least 56 decibels, which is as loud as an electric toothbrush. This artificial engine sound increases and decreases in pitch as the car speeds up and slows down, alerting pedestrians to the car's presence.

As EVs become more popular, there will be fewer ICE cars on the road, which will help to reduce noise pollution even further.

Frequently asked questions