Do loud pipes save lives?
Now you have an answer. Keep reading!
Do loud pipes save lives or do they just give us headaches?
Special thanks to all those involved in the project!
What do we analyse?
Can the sound of a motorcycle save your life? To do this, the sound of the drums must be audible to the driver in the car. Thus the sound of the motorcycle must be above the level of the background sound in the car, sound generated by the engine, music, discussions and air current when the car has over 60km / h.
In order to have an effect, the sound of the motorcycle must attract attention, i.e. it must be loud enough and it must be heard when the motorcycle is far enough away so that the driver of the car can react.
We are not used to identifying the level of a sound, so it is important to have some reference elements. Thus, the normal noises that we are surrounded by every day are in the volume range 10-60dB (A). We are quite often exposed to sounds up to 90dB (A). Prolonged exposure to more than 90dB (A) is considered to be a dangerous element to the human ear and may be subject to occupational safety.
At a rock concert the volume is at 120dB (A) while exposure to sounds over 130dB (A), even for short periods of a few minutes, is considered to be a dangerous element that can affect the hearing system.
How did we perform the tests?
The test will consist of comparing two data sets. One will be the sound, measured inside the car, generated by the operation of a motorcycle at high speed and the second will be the background sound in the car when the music is turned off or when the music is at a medium volume – volume that allows discussions with passengers without problems.
To simulate real situations, we measured the sound in the car when the motorcycle is 15m and 10m behind it, but also when the motorcycle is in the driver’s blind spot or when the motorcycle is in front of the car.
We have also analyzed the distribution of the sound emitted by the motorcycle in front and in the back at various speeds to measure the influence of speed on noise and how it is distributed in front and behind the motorcycle.
Prezentare test – video sau text
If you want all the information, you can read the detailed presentation of the test.
If you prefer the movie instead of the text, then you can find it at the link below.
Test results
How is the motorcycle heard?
The sound of the motorcycle measured in front of it is 5dB (A) lower than the sound measured behind the motorcycle. In the case of motorcycles with a very quiet drum, the engine sounds louder than the drum, so the sound measured in front is louder than that measured in the back.
More than 15m away, none of the motorcycles in the test are heard in the car – even if the noisiest motorcycle in the test produced over 110dB (A).
More than 10 m away from the car, some motorcycles may be heard. But the sound is poorly noticeable with a small difference in volume from the background sound in the car. The sound is also heard in a low frequency zone – 200-400Hz, an area where the human ear has difficulty locating the sound source.
Conclusion
- A motorcycle cannot be heard in the car (in motion) if it is at a distance of more than 15 m, no matter how modified the drum is and no matter the background noise in the passenger compartment;
- At distances of 10 m from the car, a motorcycle (with a noise level produced above the legal limits) can be heard, but the sound is in a low frequency area where the sound is difficult to identify by the human ear and is difficult to position in space-bar;
- When the motorcycle is near the car or in front of the car, the noises produced will be heard in the car at a level that attracts the driver’s attention, even when the music is at a medium level. At this distance, however, no driver`s maneuver that would endanger the motorcyclist could be prevented.
- To be heard in a car 15 m away, a motorcycle should produce a sound level at the exhaust pipe of more than 135dB (A), a condition that is impossible to accomplish in reality.
In conclusion Loud pipes save lives … is a false statement! The sound produced by a motorcycle is not heard by the drivers of the cars in front or is heard too late to be able to influence the driver’s decision.
What do we have left? Let’s be seen, not heard, and this can be done by following all the rules imposed by preventive driving. Bonus, we will have much less headaches and we will not bother the other traffic participants … useless, as the measurements show.
