Ambient noise levels on a site located in vicinity of a busy road are expected…

Concept

Sound level is measured on the logarithmic decibel (dB) scale. Environmental levels rise with the intensity and density of sources; busy traffic therefore produces much higher continuous ambient sound than quiet indoor or residential settings.

Application

A busy road combines engine, tyre-road, horn, and braking noise from many vehicles. Standard environmental reference tables place busy-road traffic roughly around 75–85 dB at a nearby site.

Contrast

• The 35–45 dB band represents quiet indoor or low-activity residential sound.

• The 50–60 dB band is typical of moderate conversation or a relatively calm office.

• The 75–85 dB band is characteristic of heavy traffic close to a busy road.

• The 110–120 dB band describes exceptionally loud close-range sources such as an amplified concert or aircraft, not routine roadside ambience.

Cross-check

An increase of 10 dB represents a tenfold increase in sound intensity. Placing busy-road traffic above conversation but below close-range amplified or aircraft noise is therefore consistent with the logarithmic scale.

Result

Therefore, the expected ambient noise range is 75–85 dB.