Low noise road surfaces : current practices in Europe

Fabienne Anfosso-LédéeFabienne Anfosso-Lédée

LCPC, FranceLCPC, France

2nd Workshop

Brussels, 24 march 2009

Recommendations for future harmonised European policies

Noise in TYROSAFE

NOISE

ROLLING RESISTANCE

TYROSAFE:

Tire and Road Surface Optimisation for Skid Resistance and Further Effects

Noise: an environmental problem

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 > 65 dB(A)).

EC regulations of noise sources since the 1970’s

Result : limited effect after 25 years : Traffic growth

Longer periods of high noise emission

More roads and spread of built areas …etc

EC Green Paper on Future Noise Policy, 1996

Noise: an environmental problem

• EC Directive 2002/49/EC :Noise mapping for major cities and large transportation

infrastructure >> need relevant noise emission models

Action plans >> need low noiseemission solutions

+ MS designate competent authorities for drawing up and adopting maps and action plans

+ MS set ambient noise limits

Noise: a difficult problem

• National regulations to protect the residentsDifferent noise indicators: LAeq, Lden, LAmax

Different legal thresholdsDifferent application schemes: calculation, check by

measurements…

Usually based on noise immission (emission + propagation)

Road noise emission

• 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

Technical

Legislation ?

• Road noise emission mainly due to tire-road interactionScientific

Legislation on road noise emission

Requirements on vehicle noise emissionDirective 70/157/EEC

Requirements on tire noise emissionDirective 2001/43/EC

CEN standards for noise barrier intrinsic performancesEN 1793 series

No requirement for road noise performance

Low noise pavements: need for requirements ?

• to promote the use of low noise surfaces

• to specify requirements in tendering procedure for low noise surfaces (indicator, level of performance..)

• to check requirements (which method ?)

• to monitor the evolution of pavements

Road authority

• to select an appropriate surfacing answering to the contract specifications

• to promote the use of its low noise product (Inland and abroad)

Road contractor

Conformity of Production

Monitoring procedure

Classification procedure

Tire/Road noise emission

Tire/road noise mitigation: the current practice in EU

Measurement methods

7,5 m

1,2 m

Statistical Pass-By (SPB) tire-road noise measurements

Limits...

restrictive site conditions spot measurement

International standard ISO 11819-1 : 1997 (currently under revision)

Characterization of low noise pavements

International standard Pr ISO 11819-2 under draft

Need (a) reference tire(s) : Pr ISO Technical Specification 11819-3 under draft

Close Proximity (CPX) tire-road noise measurementsTÜG, PL

need further comparison of devices

a relationship with SPB is missing

TRL, UK

LCPC, F

M+P, NL

Low noise road surfaces

71.8

73.8 74.1 74.375.1 75.4 75.6

77.6 77.7 77.8 78.0 78.178.6

79.3 79.580.2

80.7 81.082.1 82.2

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83.0

85.0

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LA

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)]

SPB French data base, LCPC Strasbourg (Passenger Cars @ 90 km/h and 20°C)

• Max range 10 dB(A)

• Effect of : grading porosity

• Important dispersion within a pavement type

Low noise road surfaces

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

Expected efficiency in practice: 3 – 5 dB(A) average benefit of pavement replacement at initial stage

Dense A.C. Very Thin AC Porous AC

2 layer Porous AC

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)

Classification of low noise surfaces

• 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

It is difficult to compare road surfaces in EU !

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)

0

1

2

3

4

5

6

7

no classification under consideration active classificationsystem

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Noise classification procedure

Active systems in 4 European countries

• Germany– Active since 1981– Based on CPB/SPB measurements– Passenger cars @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)

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

Noise classification procedure

• SILVIA / INQUEST (EU-FP5) classification scheme

NCAG – CEN / TC 227 group …

COP Check : CPX after 2 months texture + absorption

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

MONITORING : CPX

COP test procedure

no

sometimes

yes

no

no but interest

underconsideration

yes, active

EU Members where a procedure for COP of acoustic properties is active (set of 15)

EU members where noise specifications are introduced in tendering procedures (set of 15)

specifications, limits, requirements

indicators

methods for checking: CPX, SPB, LAeq

periods of guarantee and penalties

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 ?