Ministry of Land, Infrastructure, Transport and Tourism

Technical review of R51-03 phase3 in Japan

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Road Traffic Noise Reduction Measures in Japan

✓ To achieve 100% in the EQSs（Environmental Quality

Standards）for Road Traffic Noise

✓ To reduce the number of complaints related to vehicle

noise

◆ Targets

EQS: An administrative goal set as a standard that should be maintained for the

protection of human health and the preservation of the living environment, and

the standard value is set for each area type and time category.

.

◆ Technical review of R51-03 phase3

✓ Before introducing phase3, the following studies are nowbeing conducted in Japan

To assess the effectiveness of phase3 introduction at the

points exceeding EQSs, by using JARI prediction model

To conduct a survey of automobile manufacturers

regarding the impact of phase3 introduction, etc1

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Time-line

✓To sort out what is important as noise

countermeasures beyond phase3, we would like to

continue to share our issues and initiatives

including the technical review of phase3 in Japan.

✓We are planning to report an result of the review

at TF-VS early next year.

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Road traffic noise prediction model

based on micro traffic flow model

Japan Automobile Research Institute (JARI)

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Overview of the road traffic noise

prediction model

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Overview of the model

Features

➢ Power unit noise and tyre/road noise are treated as individual sound

sources.

➢ Running conditions and generated noise of individual vehicles in the

traffic flow are considered.

➢ Fluctuation of road traffic noise at sound receiving point is calculated

by summin up the sound propagates from each vehicle.

➢ Since the effect of noise reduction for each sound source can be

calculated individually, this model is suitable for estimating the

effectiveness of vehicle noise measures.

◆ This road traffic noise prediction model is a combination of

"micro traffic flow model" and "sound estimation model".

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Calculation flow

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Traffic condition of target road

Driving condition of each vehicle

Road traffic noise LAeq

Power unit noise

Traffic flow estimation

Sound power level of each vehicle

Noise fluctuation at recieving point

- Traffic volume for each vehicle category

- Vehicle speed- Traffic light control- Road dimension

Tire/road noise

Sound propagation

Traffic flow estimation(micro traffic flow model)

Road traffic noise estimation(sound estimation model)

騒音レベル[dB]

時間 [s]Time [s]

A-w

eig

hte

dS

PL

[dB

]

power unit noise

tire/road noise

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Traffic flow estimation

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Input data to the traffic flow model

Inflow traffic volume for each vehicle category by lane

Driving lane: Maximum speed when cruising

Traffic light placement, light indication time, Phase between

lights

Number of lanes, road dimensions, pavement type, etc.

To simulate actual traffic

flow, these values are

set based on the traffic

flow survey results

受音点-1

（交差点近傍）受音点-2

（定常走行区間）Receiving point-2

Cruising section

Receiving point-1

Near intersection

with traffic light

Inflow traffic volume of each vehicle category by each route

Vehicle speed when cruising in each section

indication time of traffic lights and phase difference between

them

Number of lanes, road dimensions, etc.

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Micro traffic flow model (car following model)

The coefficients α and β were determined based on the actual driving survey.

𝑑2𝑥

𝑑𝑡2= 𝛼 𝑉𝑜𝑝𝑡𝑖𝑚𝑎𝑙 − 𝑉𝑓𝑜𝑙𝑙𝑜𝑤 + 𝛽 𝑉𝑙𝑒𝑎𝑑 − 𝑉𝑓𝑜𝑙𝑙𝑜𝑤

𝑉𝑙𝑒𝑎𝑑 𝑉𝑓𝑜𝑙𝑙𝑜𝑤

𝑉𝑜𝑝𝑡𝑖𝑚𝑎𝑙 𝑙

𝑙

➢ In the micro traffic flow model, car following model was adopted.

➢ Running condition of a following vehicle is estimated based on that of

a leading vehicle.

Running Condition: vehicle position, speed, acceleration, engine speed

and engine load

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0.0

1.0

2.0

3.0

4.0

0 25 50 75 100 125 150 175

Acce

lera

tio

n，

m/s

2

PMR

10 km/h

0.0

1.0

2.0

3.0

4.0

0 25 50 75 100 125 150 175

Acce

lera

tio

n，

m/s

2

PMR

40 km/h

0.0

1.0

2.0

3.0

4.0

0 25 50 75 100 125 150 175

Acce

lera

tio

n，

m/s

2

PMR

70 km/h

Micro traffic flow model (Leading vehicle)

The acceleration of the leading vehicle that accelerates from the

intersection is calculated by the following formula based on the results

of the driving mode survey in urban areas.

GRB-35-inf06 (2001.09,JPN)

Excerpt

𝑎 = 3.30 − 2.15 log10 𝑉 + 0.77 log10 𝑃𝑀𝑅

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Result of traffic flow estimation

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Road traffic noise estimation

-- Setting of sound souces and sound

propagation calculation

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Expression of sound power level for each sound source

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Sound source Experimental equation of sound power level

Power unit noise

Tyre/road noise

V ：Vehicle speed [km/h]

V０ ：Reference vehicle speed (=1km/h)

B0, B1：Regression coefficient

N ：Engine speed [rpm]

N0 ：Reference engine speed (=1rpm)

T ：Engine load [%]

A0～A2：Regression coefficient

= 0+ 1 log10

0+ 2

= 0 + 1 log10𝑉

𝑉0

LA

W,E

[dB

]

N [rpm]

T = 10 %

T = 100 %

LW

A,T

[dB

]

V [km/h]

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Running condition and radiated sound power level

Change of engine speed and vehicle

speed obtained as a output of traffic flow

model

Time [s]

Engine speed

Vehicle speed

Sou

nd

po

we

r le

vel [

dB

(A)]

Time [s]

Power unit noise

Tyre/road noise

Total

Running conditions

Sound power level

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Calculated sound power levels based on

the running condition above and sound

power level equations

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Sound propagation from vehicles to sound receiving point

sound receiving point

Sound propagation

50

60

70

80

90

1200 1300 1400 1500 1600 1700 1800

A特性音圧レベル[dB]

時間 [s]

0 100 200 300 400 500 600

A-w

eig

hte

d S

PL

[d

B]

Time [s]

Sound level at the sound receiving point is calculated by summing up the

sound propagates from all vehicles. By repeating such calculations over

time, fluctuations in road traffic noise can be obtained.

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Predicted result of road traffic noise

Calculation of LAeq

50

60

70

80

90

1200 1300 1400 1500 1600 1700 1800

A特性音圧レベル[dB]

時間 [s]

0 100 200 300 400 500 600

Time series fluctuation of sound level at sound receiving point

traffic light:GreenA

-we

igh

ted

SP

L [d

B]

Time [s]

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Setting for estimating the effect of tightening limit value

Lurban [dB]

Fre

qu

en

cy [%

]

Distribution of Lurban LE (Power unit noise) + LT (Tyre/road noise)

LE [dB] LT [dB]

Engine speed N [rpm]

LW

A,E

[dB

]

Limit Reduction Reduction

Power unit noise

= 0 + 1 log10

0+ 2

Tyre/road noise

Vehicle speed V [km/h]

LW

A,T

[dB

] = 0 + 1 log10

𝑉

𝑉0

The values and frequency of the coefficients A0 and B0 are

set according to the level distribution of each sound source;

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Road traffic noise estimation

-- Validation of calculation results

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Validation: Comparison of measured and calculated LAeq

The coefficients of tyre road noise on

several types of road surfaces were set

based on the relationship between vehicle

speed and pass-by noise measured on

public roads.

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References

1) Y. Oshino, K. Tsukui and H. Tachibana, "Prediction of road traffic noise taking account of

transient running conditions of vehicles -Part 1. Relationships between running

conditions and noise radiation-," J. Acoust. Soc. Jpn. (J), 50, pp. 205-214 (1994) (in

Japanese).

2) Y. Oshino, K. Tsukui and H. Tachibana, "Prediction of road traffic noise taking account of

transient running conditions of vehicles -Part 2. Simulation of traffic flow and calculation

of noise propagation-," J. Acoust. Soc. Jpn. (J), 50, pp. 977-985 (1994) (in Japanese).

3) K. Tsukui, Y. Oshino, G. van Blokland and H. Tachibana, "Study of the road traffic noise

prediction method applicable to low-noise road surfaces," Acoust. Sci. & Tech. 31, 1,

pp. 102-112 (2010).

4) T. Suzuki, Y. Oshino and H. Tachibana, "Road traffic prediction model around

intersection taking account of right- and left- turn traffic," J, Acoust. Soc. Jpn. (J), 60,

pp. 526-535 (2004) (in Japanese).

5) T. Suzuki, K. Tsukui, Y. Oshino and H. Tachibana, "Road traffic prediction model around

signalized intersections," Proc. Inter-noise 2003, pp. 1870-1873 (2003).

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