Low noise road surfaces : current practices in Europe

1
Low noise road surfaces current practices in
Europe
2nd Workshop Brussels, 24 march
2009 Recommendations for future harmonised
European policies
Fabienne Anfosso-Lédée LCPC, France
2
Noise in TYROSAFE
TYROSAFE Tire and Road Surface Optimisation for
Skid Resistance and Further Effects
3
Noise an environmental problem
EC Green Paper on Future Noise Policy, 1996

• 20 of EU population (80 M) exposed to
  unacceptable noise levels
• annual costs caused by noise pollution estimated
  between 0.2 and 2 of GPD
• Road transport noise is the dominant source (90
  of the EC population exposed to noise levels gt 65
  dB(A)).
• EC regulations of noise sources since the 1970s
• Result limited effect after 25 years
• Traffic growth
• Longer periods of high noise emission
• More roads and spread of built areas etc

4
Noise an environmental problem

• EC Directive 2002/49/EC
• Noise mapping for major cities and large
  transportation infrastructure gtgt need relevant
  noise emission models
• Action plans
• gtgt need low noise
• emission solutions

• MS designate competent authorities for drawing
  up and adopting maps and action plans
• MS set ambient noise limits

5
Noise a difficult problem

• National regulations to protect the residents
• Different noise indicators LAeq, Lden, LAmax
• Different legal thresholds
• Different application schemes calculation, check
  by measurements
• Usually based on noise immission (emission
  propagation)

6
Road noise emission
Technical

• Different tools to reduce road noise emission
• improve vehicle / tire conception
• Improve road surface conception
• Build noise barriers
• Traffic management speed limits, reduce traffic
  volume (re-routing), increase fluidity

7
Legislation on road noise emission
8
Low noise pavements need for requirements ?
9
Tire/Road noise emission

• Tire/road noise mitigation the current practice
  in EU

10
Measurement methods
Statistical Pass-By (SPB) tire-road noise
measurements
International standard ISO 11819-1 1997
(currently under revision)
1,2 m
7,5 m
Limits... Ø restrictive site conditions Ø spot
measurement
11
Characterization of low noise pavements
Close Proximity (CPX) tire-road noise measurements
International standard Pr ISO 11819-2 under
draft Need (a) reference tire(s) Pr ISO
Technical Specification 11819-3 under draft

• need further comparison of devices
• a relationship with SPB is missing

12
Low noise road surfaces

• Max range 10 dB(A)
• Effect of
• grading
• porosity
• Important dispersion within a pavement type

SPB French data base, LCPC Strasbourg (Passenger
Cars _at_ 90 km/h and 20C)
13
Low noise road surfaces

• Several techniques available
• Porous pavements, single or double layers
• Thin semi-porous layers with small aggregate size
• Rubber asphalts

Very Thin AC
Porous AC
Dense A.C.
Expected efficiency in practice 3 5 dB(A)
average benefit of pavement replacement at
initial stage
14
Low noise road surfaces
Problem of ageing of acoustic performance of low
noise road surfaces
Example of Porous Asphalt Concrete 0/10 (French
data base)
15
Classification of low noise surfaces
It is difficult to compare road surfaces in EU !

• No common names (definition) of pavement products
• No common definition of low noise surfaces
• ? performance indicator RSI (UK), Cwegdek (NL),
  Lm25 (D), LCPX (DK, Fin), LAmax (F),LMA (A),
  LAeq(24h) (S)
• ? classification procedures. Active
  classification scheme in 4 countries D, DK, NL,
  UK

16
Classification of low noise surfaces
EU Members with a noise classification system of
road pavements (results from a questionnaire in
TYROSAFE, set of 15 countries)
17
Noise classification procedure
Active systems in 4 European countries

• Germany
• Active since 1981
• Based on CPB/SPB measurements
• Passenger cars _at_120 km/h
• Reference indicator Lm(25) nicht geriffelter
  Gussasphalt
• Min. 5 sites

• Netherlands
• Based on SPB measurements, 5 m high
• Reference indicator Cwegdek, reference pavement
  DAC 0/16
• Car trucks, with different reference speeds
  according to roads
• Average on 5 worksites if within 2 dB(A)

18
Noise classification procedure

• U.K. (HAPAS)
• Based on SPB measurements
• Reference indicator RSI difference between
  the traffic noise level calculated from SPB tests
  and the theoretical level for the reference
  surface
• Reference surface newly-laid 20 mm Hot Rolled
  Asphalt.
• Reference speeds for PC trucks according to
  road high speed (110/90 km/h) or medium speed
  (80/70 km/h)
• Min. 2 sites

• Danemark
• Based on CPX measurements
• 5 classes ranging from A (particularly good) to E
  (no noise reduction)
• Reference speeds 50 km/h and 80 km/h

19
Noise classification procedure

• SILVIA / INQUEST (EU-FP5) classification scheme

• CLASSIFICATION SPB
• texture
• CPX (for SPB spot assessment and further COP
  checks)
• sound absorption

• COP Check CPX after 2 months
• texture absorption

• MONITORING CPX

20
COP test procedure
EU members where noise specifications are
introduced in tendering procedures (set of 15)
EU Members where a procedure for COP of acoustic
properties is active (set of 15)

• ? specifications, limits, requirements
• ? indicators
• ? methods for checking CPX, SPB, LAeq
• ? periods of guarantee and ? penalties

21
Conclusions

• Measurement methods
• Existing (relative) consensus on 2 methods SPB
  and CPX
• CPX, SBP, but also proxi method needs to be
  further developed and validated
• Harmonised Noise Classification of road surfaces
  do we need one ?
• Harmonised COP test procedure do we need one ?
• How to integrate evolution over time of
  performances ?