Soundproofing Against Road Traffic Noise
When it comes to soundproofing for road traffic noise there are a few key factors that we need to consider before deciding on the correct solution:
- The type of traffic (trucks, cars, motorbikes)
- The type of road (A-roads, residential streets with speed bumps, etc.)
- The distance between the property and the loud road
Noise From Vehicles
In order to understand the noise emission levels from vehicles there are 3 key factors to consider: speed, acceleration and a constant for the vehicle (such as the size of the car and the average frequency range).
Examples of Road Traffic Noise
Regardless of where you live, ‘light vehicles’ – i.e. average-sized cars – will account for most of the traffic noise. Even in areas where the percentage of heavy vehicles is more than usual, the noise of normal cars will still dominate, as they tend to travel at faster speeds.
Cars produce two types of noise: propulsion noise and tyre noise. Under 34 mph, propulsion noise is the main issue, and over that speed, the sound of the tyres on the road becomes the main cause of noise pollution. However, due to advancing engine technologies, tyre noise from new vehicles can become an issue at just over 12 mph.
- The legal noise limit for a car exhaust in the UK is 82dB.
- The average car produces 62dB driving at 30 mph.
- At 50 mph, a car produces noise emissions of ~70dB.
Car Noise Pollution Reduction
It has been found that in residential areas in which the speed limit is between 20-30 mph, reducing the limit by just 6 mph can cut noise levels by 40%. On urban motorways a reduction from 70 mph to 60 mph cuts noise pollution from light vehicles by up to 50%. However, the same reduction in speed does not equate to the same reduction in road traffic noise pollution for heavy vehicles.
In some cases, acceleration accounts for 10% of traffic noise, and so the installation of speed bumps will, theoretically, work to reduce noise pollution – however, in reality, most drivers accelerate and decelerate between the bumps, as well as creating impact noise when they reach the bump.
When it comes to road traffic noise pollution trucks are disproportionately responsible due not only to their size, but the height of their diesel stack. This can be a particular problem on smaller backstreets where the truck is likely to accelerate and decelerate, and where body rattle is more audible. In areas where trucks make frequent deliveries, the reversing siren is yet another pain point that will need to be factored into any soundproofing solution.
- Drop-sided trucks produce noise in the range 40-50 Hz mostly due to exhaust noise.
- HGVs have two frequency peaks: 63 Hz and 630 Hz, due to exhaust and body rattle.
Whether it’s your neighbour revving their engine first thing in the morning, or part of the passing traffic, the noise from motorbikes can be especially intrusive. There are restrictions on the maximum noise levels for a motorbike, yet these vary depending on when the bike was first used, meaning that you can often hear bikes producing noise of over 80dB – and mostly in the low and mid-low range that can be tricky to combat.
- Cruiser bikes (i.e. Harley Davidson) produce noise that tends to lie predominantly in the 100-400 Hz range. 84.8dB Lmax
- Mopeds and scooters tend to dominate the 1000-2000 Hz range, with a broad range from 200-5000 Hz. 62.3dB Lmax
- Sports bikes tend to have a fairly flat spectrum in the 125-8000 Hz range. 78.3dB Lmax
Road Traffic Noise Solutions
As you can see from above – to soundproof against road traffic noise is a complicated business which requires a solid understanding of the specific noise complaint. To find the most effective soundproof solution, consider taking a noise survey, which will measure the decibel level of the traffic noise, as well as the frequency. The results of the noise survey will help to create a solution that will work against the specific type, volume and range of noise that your property most frequently encounters.
Our Wall Soundproofing Systems
The window is the weakest link in any property’s soundproof abilities. Unless the windows are adequately soundproofed – and professionally installed – they will let in a great amount of noise pollution. Installing specialised windows that are fitted with glazing of two different thicknesses to combat the resonance frequency of your specific noise complaint, will be most effective.
Typically, a wall will be a good insulator of sound, yet they can also be prone to problems -the most common of which relates to gaps in the structure itself. By locating and plugging these gaps with acoustic materials and installing soundproof ventilation where necessary, road traffic noise will be blocked from entering your property.
Whether around the frame or through the door itself, often road traffic noise can find an easy way to get in through your doors. In many cases the professional installation of soundproof doors will drastically cut the level and volume of noise pollution that enters your property.
How to Minimise Road Traffic Noise Yourself
If you’re looking to reduce road traffic noise but cannot currently make substantial changes to your property, there are a number of solutions that you can try for yourself. Please bear in mind that these solutions will not be as effective as installing new windows and doors, or plugging the gaps in your walls.
- Use insulating tape around your windows and doors to prevent noise entering through any cracks.
- Noise blocking curtains provide another barrier against noise entering inside the home.
- Trees planted around the perimeter of the home will reflect the noise back onto the street.
- Erecting a solid fence will also reflect the noise back onto the street.