Knowledge Centre · Understanding Noise
What is LA10?
LA10 can be thought of as the noise level exceeded for 10% of the measurement period — one of the most commonly used descriptors for assessing road traffic noise.
Read time
2 minutes
Relevant to
Anyone reading a noise report or condition
What LA10 stands for
LA10 stands for: A-weighted Noise Level Exceeded for 10% of the Measurement Period.
Fortunately, it is much simpler than it sounds.
LA10 can be thought of as the noise level that is exceeded for 10% of the measurement period. It is commonly used to describe the higher noise levels that occur regularly, particularly from road traffic..
A changing sound level, representing the louder noise levels
Most environmental noise is constantly changing. A truck passes, then a quieter car, then perhaps a motorcycle. The noise level rises and falls throughout the measurement period.
LA10 identifies the noise level that is exceeded for 10% of the time. Rather than averaging all noise levels like LAeq or recording the single loudest event like LAmax, LA10 represents the louder noise levels that occur regularly throughout the measurement period.
If you measured traffic noise over one hour and recorded an LA10,1hour of 72 dB(A), this means the noise level exceeded 72 dB(A) for 10% of that hour—approximately 6 minutes. It represents the louder traffic conditions experienced during the measurement period rather than isolated peak events.
Where LA10 is used
LAeq is one of the most commonly used noise descriptors in environmental acoustics and is used extensively for:
- Road traffic noise – one of the most common descriptors used to assess traffic noise.
- Transportation planning – evaluating the impact of new roads and road upgrades.
- Urban planning – evaluating traffic noise near residential and commercial developments.
- Historical traffic noise assessments – used in many Australian and international traffic noise guidelines and studies.
- Construction projects – assessing louder operational periods during construction activities.
Related reading
Try the calculator
See how multiple sound levels combine logarithmically, not by ordinary addition.
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