3.4.3.2.13 - pollution - road traffic noise pollution

how is road traffic noise levels measured?

- LA10 measures noise exceeded for 10% in any set period

- good measure of the noisiest periods

- LA90 measures the noise level exceeded for 90% in any set period

- good measure of the quietest periods

what is the Traffic Noise Index (TNI)?

this produces a representative measure of traffic noise using LA10 and LA90

L10 (18h)

- measures assumes that traffic noise is only a problem between 6am and midnight

- noise level that is exceeded during the noisiest 10% of each of these 18 hours is measured

- the mean of these 18 levels is then calculated

controlling wheel noise

sound absorbing road materials such as porous asphalt or asphalt that includes shredded rubber from old vehicle tyres

controlling vehicle air turbulence

improved vehicle aerodynamics

controlling engine noise

acoustic insulation around the engine to produce quieter exhaust pipes

controlling general road vehicle noise

- traffic may be rerouted to avoid more sensitive (usually residential) areas

- traffic management to produce free flow of the traffic reduces the louder noise produced during acceleration

- fences, embankments, walls and dense tree planting can help to absorb noise around roads

- double glazing can reduce noise levels within buildings