Acoustical classification and conformity checking on road surfaces

1
Acoustical classification and conformity checking
on road surfaces

• Johan Lang
• Swedish Road Administration

2
Situation in Sweden

• Road noise is a critical and increasing problem
• The socio-economic cost for noise disturbances is
  estimated to 1 billion per year
• National Environmental Quality Goal
• The number of persons exposed to disturbing
  traffic noise exceeding the guidance values set
  by the Government for indoor levels shall have
  decreased by 5 percent by 2010 compared to 1998

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Situation in Sweden

• Long term goal
• No persons shall be exposed to disturbing traffic
  noise exceeding the guidance values set by the
  Government
• Road Traffic Noise Guidance Values
• 30 dB(A) equivalent level indoors
• 45 dB(A) maximum level indoors at night time
• 55 dB(A) equivalent level outdoors at the
  building front
• 70 dB(A) maximum level at a patio connected to a
  dwelling

4
Situation in Sweden

• SRA has focused on measures to bring indoor noise
  down.
• There has been a reduction in the degree of
  disturbances, but the number of persons exposed
  to road traffic noise are not decreasing.
• On the contrary, traffic noise disturbances will
  increase, due to the increasing traffic volume
  and urbanisation.
• Measures like changing windows and building noise
  barriers only, are not sufficient to achieve the
  goals

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Change in strategy
Measures to reduce the emission (noise
generation) Vehicles Tyres Road surface
Measures to reduce the immission (noise
propagation) Change windows Noise
barriers Facade insulation
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Low-Noise Pavements

• Swedish pavements are among the noisiest in
  Europe 5-10 dB(A) higher than European average
• Focus has been on resistance agains wear of
  studded tires and bearing capacity.
• Higher focus on road noise will change this and
  low-noise pavements will be considered.
• A strategy for choice of pavements with regard to
  noise is under development.

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Low-Noise Pavements Important Issues

• Low-Noise durability
• Lifetime
• Cost-Benefit
• Air pollution - particles
• Traffic Safety friction
• Rolling resistance

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Acoustical classification and conformity checking
to be used

• Road noise monitoring
• Performance contracts

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Extensive international work concerning road
traffic noise has been carried out
An European standard is a way to coordinate these
efforts
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Acoustical classification and conformity checking
Need of RA

• Tyre/road noise measurement methods that can be
  used in urban areas for different tyre types. The
  methods must characterise the tyre/road noise
  contribution to the total traffic noise emission.
  
• Acoustical classification methods that makes it
  possible to predict the expected tyre/road noise
  emission for a road surface

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Summary

• Road noise is a critical and increasing problem
  in Sweden.
• We are moving into a higher focus on reducing
  noise emissions, which includes low-noise
  pavements.
• It is time to coordinate all international work
  concerning road surface/tyre noise into European
  standards

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Acoustical classification and conformity checking
Need of standards

• Tyre/road noise measurement methods CPX and SPB
• Megatexture
• Sound absorption
• Acoustical classification
• Part 1 Labelling
• Part 2 Confirmity-on production
• Mechanical impedance