Effective Strategies for Noise Control in Site Planning.

07 Sketches
Jun 8
4 min read

Introduction

In any residential or urban setting, managing unwanted noise is an important part of creating comfortable living environments. One of the most effective ways to do this is by carefully planning the placement and design of sound barriers. Whether it's traffic noise, industrial sounds, or general urban disturbances, controlling sound through thoughtful site planning can significantly improve the quality of life for residents.

In this illustration, I’ve explained various scenarios showing how barrier placement affects sound travel. By understanding the concept of shadow zones, diffraction angles, and line-of-sight interruption, we can design more efficient and effective noise control solutions. Let’s walk through each example to better understand how sound behaves and how we can design our spaces to reduce its impact.

First Scenario – Correct Barrier Placement - Maximize the Diffraction Angle

In this case, the barrier is placed close to the house and is tall enough to create a large shadow zone. This wide diffraction angle helps redirect and weaken the sound waves significantly. As a result, the house is better protected from the incoming noise. This is an ideal placement, as it efficiently uses the geometry of the site to reduce sound penetration.

Second Scenario – Incorrect Barrier Placement - Ineffective Diffraction

Here, the barrier is placed closer to the source but is not high enough or strategically positioned. As a result, the sound waves bend around the top and still reach the house. The shadow zone is too narrow to be effective, and the line of sight is not fully blocked. This setup provides minimal noise reduction and is inefficient in real-world applications.

Third Scenario – Effective Use of Topography - Interrupt Line of Sight

In this example, the barrier is placed along a downward slope, taking advantage of the terrain. The line of sight between the truck and the house is interrupted, and the barrier height is sufficient to form a broad shadow zone. This effectively blocks sound travel. It demonstrates how combining barrier placement with natural landforms enhances sound control.

Fourth Scenario – Increasing Barrier Height - Enhanced Performance

This final setup shows the barrier placed similarly to the third example, but with added height. This improvement extends the shadow zone even further and ensures minimal noise leakage. It emphasizes that increasing barrier height, when possible, is a simple yet powerful way to enhance acoustic performance.

In this Illustration ,I have demonstrated the importance of landform design specifically the use of berms for effective noise control and privacy in residential site planning. It compares two different scenarios: one with a berm and one without, highlighting how thoughtful terrain modifications can dramatically improve comfort and acoustics.

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Effective Noise Control Using a Berm

In this example, a berm a raised landform is created between the noise source (a road with vehicles and people) and the house. This elevation acts as a natural barrier, interrupting the direct path of sound waves. The presence of trees further supports noise deflection and visual screening. The result is a shadow zone, where noise is significantly reduced, ensuring both acoustic comfort and visual privacy for the home. This approach also blends seamlessly into the landscape, making it both functional and aesthetically pleasing.

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Bottom Scenario – No Noise Control or Privacy

Here, no berm is present, and the land remains flat between the road and the house. As a result, sound travels directly and uninterrupted to the house, making the residents vulnerable to noise like honking and street conversations. Additionally, there is no visual separation, leading to a lack of privacy. This scenario illustrates an ineffective design that fails to consider acoustic or spatial separation.

Each method demonstrates a way to reduce the impact of sound waves from vehicles like honking and engine noise. Let’s explore each one:

1. Bank of Earth

A raised mound of soil, also called a berm, is positioned between the road and the house. It partially blocks sound but may allow some noise to diffract over it. It's a natural and cost-effective solution, though not the most efficient on its own.

2. Wall

A constructed barrier directly stops sound waves from reaching the home. This method provides strong and immediate noise reduction. The effectiveness depends on the height and material used. It’s a reliable and direct approach for blocking traffic noise.

3. Trees

A line of dense vegetation or trees acts as a visual and partial acoustic buffer. While not as effective as solid barriers, trees help reduce high-frequency noise and improve aesthetics. They are best used in combination with other solutions.

4. Sunken Carriageway

Here, the road is lowered into a trench-like section, keeping vehicles below the level of surrounding buildings. This design traps and reflects sound waves within the depressed carriageway, offering excellent long-term noise reduction.

Case Studies:

1. Delhi-Gurgaon Expressway (India) – Noise Barriers Installation

Context: Residential colonies near the expressway complained of high noise pollution.
Solution: Vertical noise barriers (acrylic and metal panels) were installed.
Result: Sound levels dropped by 5–7 dB in adjacent homes.

2. Sound Berms in Irvine, California (USA)

Context: Suburban communities near freeways experienced traffic noise.
Solution: Landscaped berms were created using mounded earth and plantings.
Result: Combined aesthetics with functional noise deflection.
Earth berms work well in open-space planning and blend into the landscape.

3. The Big Dig – Boston, Massachusetts (USA)

Context: Heavy traffic caused unbearable noise for city dwellers.
Solution: Major highways were moved underground (sunken carriageways).
Result: Significantly reduced urban noise and reclaimed surface space.
Sunken carriageways are highly effective but costly, ideal for large-scale projects.

Noise mitigation in urban design involves a balance between form, function, and environment.

Using physical barriers natural or built can significantly reduce unwanted sound. The sunken carriageway offers the most effective passive solution. Tree lines and berms provide a softer, landscape-integrated approach. Thoughtful planning ensures quieter and more livable spaces near busy roads.

Thanks for reading!