Environn~nt International, Vol. 16, pp. 561-566, 1990 0160-4120/90 $3.00 +.00 Printed in the U.S.A. All fights reserved. Copyright 01990 Pergamon Press ple

THE EFFECT OF VIBRATION ON NOISE ANNOYANCE: A SURVEY ON TRAFFIC NOISE AND VIBRATION IN SAPPORO

Tetsumi Sato Faculty of Engineering, Hokkai Gakuen University, Sapporo 064, Japan

E188-213 (Received 15 October 1988; accepted 27 April 1990)

The purpose of this study is to clarify the contribution of road traffic vibrations to the noise annoyance responses of residents in the community of Sapporo, Japan. The surveyed houses were all detached wooden structures and the total number of effect ive respondents were 219. The survey comprised attitude interviews with the people l iving in the houses and physical measure- ments outdoors. The key questions were about annoyance due to road traffic noises and how bothersome the road traffic vibrations are. The answers were given on a f ive-point category scale. By the analysis of the sound levels and the vibration levels, the 13 surveyed areas were classified into two groups. At the same noise exposure levels, the areas in the first class had higher vibration levels than those in the second. The statistical analysis showed a significant difference between the annoyance responses of the high vibration areas compared to those of the low vibration areas. The main result is that people are more annoyed by the same traffic noise in the areas where traffic vibrations are more severe.

INTRODUCTION

There are many factors which influence the annoy- ance responses of a community. Among them, vibra- tion is one of the most important factors because most noise sources simultaneously cause vibration. Dose-response relationships of road traffic vibrations as well as those of noises have been widely surveyed. In several surveys the simultaneous impact of noise and vibration has been evaluated, but the total scope of this interaction has not been clarified. Fleming and Griffin (1975) performed an experiment to determine the subjective equivalence of pure tone noise and sinusoidal whole-body vertical vibration. The large variability due to intersubject differences were rec- ognized, but the subjects could compare the noise with the vibration on the same scale of "displeasure". Nishinomiya (1976) summarized a number of sur- veys on social responses to noise and vibration. He mentioned that the most significant factor to decide the attitude toward the vibration was not the vibration

exposure level, but the annoyance of noise caused by the vibration source. Tokuyama (1982) investigated the subjective responses to the combined input of noise and vibration. His experimental result indi- cated that the total annoyance was increased by add- ing the vibration stimuli to the noise.

In this paper, the contribution of the road traffic vibrations to the annoyance of noise is evaluated.

OUTLINE OF SURVEY

After the preliminary survey, 13 residential areas in Sapporo City were selected as the target areas. In each area, two or three blocks containing about ten houses were selected where the distances from traffic roads were nearly equal. An example is shown in Fig. 1. The surveyed houses were all detached wooden struc- tures and the total number of effective respondents was 219.

The survey comprised attitude interviews and phys- ical measurements. As a rule, the interviews were

561

562 T. Sate

' , L . ~ - - ; - : ~ - - - ~ : ~ . . . . . . . . . . - , - - - - - " ," f ~

. . . . . . . . . . . . . . . .

r /~ . . . . . . . -9 . . . . . . ~ ~ ' . . ' ~ q 2.~/.~ ki / / ,

. . . . . . - - ~ 2 . _ _ " _ . 2 , _ - 2 " - ' " ~ _ _ , . _ - - : . . . . . . . ~ . _ _ , _ ~ _ _ L J _ L _ . - - ~ - - I - - - - ~

. - . _ - _ . : - ~ ~ - . . ~ . . . . . . . . . . . . . . . . . . m a i n s t r e e t . - -

. . . . . . . . . . . . . - . , , i - - r 1 - r -- 1 - I " "

I [ ~ " . to, , I I r / l i ,

Fig. 1. An example of the surveyed area. This area (No.13) was divided into three blocks and the physical measurements were carried out at positions 1, 2 and 3.

(1)

(2)

How much does the traffic noise from the main street annoy you? 1. very 2. fairly 3. slightly 4. not so much 5. not at all

How much does the traffic vibration from the main street bother you? 1 very 2. fairly 3. slightly 4. not so much 5. not at all

Fig. 2. Key questions on annoyance by noise and vibration.

made with housewives living in the houses. The ques- tionnaire contained 32 questions for the respondents and nine items to be filled out by the interviewers. Key questions were about the annoyance of road traffic noise and how bothersome the road traffic vibrations are. These were to be answered on a five- point category scale (very, fairly, slightly, not so much, not at all) as shown in Fig. 2. After the inter- views were completed, physical measurements were carried out both in terms of noise exposure levels and vibration levels (measured only in the vertical direc- tion on the ground). These levels were measured at one outdoor position in each block as shown in Fig. 1 and recorded for 10 rain every 4 h at 3, 7, 11, 15, 19 and 23 by using a sound level meter (RION NA-20), a vibration level meter (RION VM-14B) and a level recorder (RION LR-O4). The following measures of sound and vibration levels were used in this study: Leq(24) = A-weighted sound level of a constant sound having the same sound energy as an actual time- varying sound over 24 h, dB(A); VL10 = frequency

weighted (JIS C 1510, ISO 2631/2) vortical vibration level exceeding 10% of the time over 24 h, dBV. Leq(24) and VL10 were calculated from 720 levels which were obtained from data taken at 5 s intervals over 60 rain.

In order to avoid bias, questions on noise wore not preceded by those on vibration. Field measurements wore also carried out after the interviews were com- pleted.

RESULTS AND DISCUSSIONS

Fig. 3 shows the relationship between the noise and the vibration levels for the 13 surveyed areas. Leq(24) and VL10 are the scales generally used in Japan for the measurement of noise and vibration levels. By the analysis of Leq(24) and VL10, the 13 areas were classified into two groups. The areas of the first group (Nos. 4, 5, 6, 9, 10, 11, 12 and 13) had higher vibration levels than the areas of the second

Effect of vibration on noise annoyance 563

6 0 -

1>

s o - IC

~ 4o-

>

- 30- t -

O

B 2 c -

lO 30

~ ( g r o u p

I I I I I 1 40 50 60 70 80 90

noise level (Leq(24)) in dBA

2)

Fig. 3. Comparison of sound levels and vibration levels in each area. Thirteen areas were classified into two groups.

group (Nos. 1, 2, 3, 7 and 8), with all having the same range of noise level.

Fig. 4 compares the annoyance responses for the two groups to noise and vibration. The response tend- encies to noise and to vibration are clearly different in these two groups. The annoyance from noise as well as from vibration were both stronger in the areas of the first group, that is, where the traffic vibrations were more severe.

Fig. 5 shows the responses to the questions on activity disturbances and related effects. The ordi- nate is the percentage of positive responses (fre- quently, often, sometimes), the abscissa is the scale of the annoyance due to noise or due to vibration and the parameters are the items of disturbances or re- lated effects. Fig. 5 shows that from people who responded with "very or fairly annoying" disturbance descriptions such as "kept from sleep" and "woken up" appear with greatest frequency, followed by "irritated", "startled", "conversations disturbed" and "TV receiving or telephoning disturbed". Symptom descriptors such as "ear ringing" and "headache" were rarely used. Fig. 5 shows that the indirect vibrational effects like "vibration of fittings or utensils" are cited frequently. Considering that the vibration lev- els in each area are relatively small, only a small percentage of people may feel the whole body vi- brate. A large percentage of people who responded "very or fairly bothersome" may feel disturbed by the sounds caused by the vibration of windows, table- ware and so on.

The relationship between the annoyance responses and the properties of respondents as well as the phys- ical factors such as the sound level were analyzed by a multivariate analysis by Hayashi, Case II (Ando and Hattori 1973; Tanaka et al. 1984) which has often been used for analyzing category data of question- naires in Japan. This method corresponds to the method of a discriminant analysis with a dummy criterion (outside) variable and dummy explanatory variables. The method produces quantified numerical values (category score) that have a common scale for each category of explanatory items and a criterion item.

e'/o)

50

(O/o)

50

(group 2) (group 1)

. . ' '4"~S-

I I I I 0 5 4 3 2 1 .C

onnoying

Fig. 4. Distributions of annoyance responses to noise and

~ 2)

. . . . . . )

I I I I 5 4 3 2 1

.C

o E _c -- ~. O ~ ' ~ 0 ' - - "-- ¢,' co c~ -~ 2 >

bothersome

responses of being bothered by vibration.

564 T. Sato

100

C 0 O.

50

0 n

~6

( 3 .

~ ! ~ I0C

Ji i=- 50

0

o. kept from sleep b. woken up c. irritation d. startled e. ear ringing f. headache / g. conversations

disturbed h. TV receiving or /

telephoning . / I "

0 5 4 3 2 1

r- > ,

Z ~ . c > '

0 . . - , O 0 0 co cm -~ ~ >

annoyi ng

m

a. kept from sleep b. woken up c. irritation d. startled e. vibration of / ~ f

fittings / (ex. window) / /

f. vibration of / / o~ utensils / / / b

I I I 5 4 3 2 1

r" ~ , u

o E & "= ~"

bothersome

Fig. 5. Relationship between annoyance responses due to noise and responses of being bothered due to vibration, and activity distur- bances and related effects. Positive responses include the categories of "frequently, often, sometimes".

Table I. Result of a multivariate analysis by Hayashi, Case II. (Case of using only sound level as physical factor).

Items Cat. Freq. Cat. score Range Partial car,

-29 : (14) 1.37055 1.72979 0.21072 30-39 : (57) -0.09716 40-49 : (59) -0.22043 50-59 : (41) -0.35923 60- : (48) 0.29342

I. Age

2. Sex male : ( 4 l ) 0.11635 0.14315 0.02816 female : (178) -0.02680

3. Inhabitancy years

-2 : (15) -0.95431 2-4 : (38) -0.17295 4-6 : (48) 0.22995 6-8 : (23) -0.21622 8- : (95) 0.15602

4. Presence of presence occupation absence

5. Noise level, -55 Leq(24) 55-60

60-65 65-

6. Noise annoyance I (Outside variable) 2

3 4 5

: (57) -0.00435 : (162) 0.00153

: (29) 2.04563 : (58) 0.22812 : (57) -0.12303 : (75) -0.87389

1.18426 0.15611

0.00588 0.00133

2.91952 0.44776

: (19) -0.68110 (very) : (47) -0.21820 ( f a i r l y ) : (76) -0.27368 (s l ight ly ) : (52) 0.33134 (not so much) : (25) 1.07064 (not at a l l )

Correlation ratio eta-square = 0.23338

Effect of vibration on noise annoyance 565

Table 2. Result of a multivariate analysis by Hayashi, Case If. (Case of using both sound level and vibration level as physical factors)

Items Cat. Freq. Cat. score Range Partial cor.

I. Age -29 : (14) -0.93691 1.13924 0.17766 30-39 : (57) 0.08656 40-49 : (59) 0.02429 50-59 : (41) 0.20233 60- : (48) -0.03221

2. Sex male : (41) 0.00746 0.00917 0.00254 female : (178) -0.00172

3. Inhabitancy -2 : (15) 0.48372 0.56699 0. I0671 year 2-4 : (38) 0.13714

4-6 : (48) -0.07023 6-8 : (23) -0.05152 8- : (95 ) -0.08328

4. Presence of presence : (57) 0.04713 0.06371 0.02026 occupation absence : (162) -0.01658

5. Noise level, -55 : (29) -0.26163 0.95191 0.28058 Leq(24) 55-60 : (58) -0.52737

60-65 : (57) 0. III12 65- : (75) 0.42454

6. Vibration level, -20 : (27) -1.87162 2.69069 0.53588 VLIO 20-25 : (43) -0.50305

25-30 : (13 ) 0.03411 30-35 : (23) -0.03712 35-40 : (64 ) 0.50689 40- : (49) 0.81907

7. Noise annoyance l : (19) 0.83372 (very) (Outside variable) 2 : (47) 0.55859 ( fa i r ly )

3 : (76 ) 0.22455 (sl ight ly) 4 : (52) -0.59572 (not so much) 5 : (25) -1.12732 (not at a l l )

Correlation ratio eta-square ffi 0.37410

Table 1 is the result of this analysis using only sound levels as the phy.~ical factor, and Table 2 is that of the analysis using both sound and vibration levels. A high correlation ratio is obtained in the latter case. Through these two analyses, it is found that the vibration level contributes to the noise annoy- ance.

In Fig. 6, the dose-response relationships of the noise annoyance are shown graphically, both for the first group areas with high vibration levels and for the second group areas with low vibration levels. The ordinate is the scale of relative cumulative frequencies of the positive responses (very, fairly, slightly annoying), assessed every 2 dB(A) steps of Leq(24) and the abscissa is the Leq(24). The ranges of

sound levels are almost the same in both categories but 50% of those who described the noise as "annoy- ing" lived in areas with noise levels not exceeding 62 dB(A), for the first class group, and 68 dB(A) for the second class group. The difference of these two levels is about 6 dB(A). Table 3 gives the result of the non-parametric analysis by Kolmogorov-Smirnov (Ando and Hattori 1973; Hidano et al. 1961). There are two reasons for using this non-parametric test. One is that the kind of structural distribution of the pop- ulation of respondents with respect to the sound lev- els is not clear (it might not normally distributed) and the other is that the decibel scale is r e p r e s e n t e d by an ordinal scale. The analysis by the Kolmogorov- Smirnov test shows there is a significant difference

566 1". Sato

1.0

tJ C

= (gro O" -

w~

>

=00.5 E group 2) D u

t .

0 50 55 60 65 70 75

noise level (Leq(24)) in dBA

Fig. 6. Comparison of positive annoyance responses of two groups. Positive annoyance responses include the categories of "very, fairly, slightly".

Table 3. Result of the Kolmogorov-Smirnov Test. S I(X) and S2(X) stand for the relative cumulative frequencies of positive annoyance responses.

Leq(24) 52-54 54-56 56-58 58-60 60-62 62-64 64-66 66-68 68-70 70-72

Sl(X) sz(x)

0.052 0.082 0.144 0.361 0.474 0.588 0.845 0.969 1.000 1.000 0.044 0.044 0.044 0.156 0.244 0.289 0.289 0.578 0.867 1.000

ISI(X)-S2(X)I 0.008 0.038 O. lO0 0.205 0.230 0.299 0.556 0.391 0.133 0.000

1. two ta i led test: 0.0~ =1.63~/(97+45)/(97x45) =0.294. D=max. lSl(X)-SZ(X)l=0.556, D> D.o,, significance of IZ level

2. one tailed test: X ~=4x(o.556)2x(97x45)/(97+45)=38.0, X~o,(2)=9.21 X z >X~(2) , significance of IZ level

of 1% between the annoyance responses of high vi- bration areas and those of low vibration areas. People were more annoyed by the same traffic noise in the areas where traffic vibrations were more severe. Road traffic vibration appears to affect the noise annoy- ance responses of the community and people seem to respond to the annoyance of both noise and vibration equally if they are asked only about the annoyance due to noise, There are many factors which cause road traffic-vibration including the nature of automo- biles, surface conditions of road and house structures. However, the vibration level is the objective factor which can be measured. Therefore the finding of this study can be utilized for the prediction of the annoy- ance responses of the community.

REFERENCES

Ando, Y.; Hattori, H. Statistical studies on the effects of intense noise during human fetal life. L Sound Vib. 27:101-110; 1973.

Fleming, D.B.; Griffin, M.J. A study of the subjective equiva- lence of noise and whole-body vibration. J. Sound Vib. 42:453- 461; 1975.

Hidano, T.; Setani, M.; Okawa, N. Statistics for psychology and pedagogy. Tokyo: Baihukan; 1961:89-94 (in Japanese).

Nishinomiya, G. Significant characteristics of social response to noise and vibration. L Acoust. Soc. Jpn. 32:147-155; 1976 (in Japanese).

Tanaka, Y.; Tarumi, T.; Wakimoto, K. Handbook of statistical analysis for personal computer, II (Multivariate Analy- sis). Tokyo: Kyoritsu-Shuppan; 1984:270-295 (in Japan- e s e ) .

Tokuyama, H. Subjective response to combined input of noise and vibration. J. INCE/JAPAN 6:157-161; 1982 (in Japan- ese).