Journal of Transportation Technologies, 2013, 3, 190-193
http://dx.doi.org/10.4236/jtts.2013.33019 Published Online July 2013 (http://www.scirp.org/journal/jtts)
Relationship between Road Traffic Accidents and
Drinking Habits in All 47 Prefectures of Japan
Nobuyuki Miyatake1, Naoko Tanaka2, Noriko Sakano1, Hiroshi Kinoshita2
1Department of Hygiene, Faculty of Medicine, Kagawa University, Kagawa, Japan
2Department of Forensic Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan
[e-mail], [e-mail]
Received April 1, 2013; revised May 1, 2013; accepted May 9, 2013
Copyright © 2013 Nobuyuki Miyatake et al. This is an open access article distributed under the Creative Commons Attribution Li-
cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
We evaluated the road traffic accidents and drinking habits in all 47 prefectures of Japan by ecological study. Data on
traffic accidents were obtained from Ministry of Internal Affairs and Communications, Japan. Drinking habits were also
obtained from Ministry of Health Labour and Welfare and The General Insurance Association of Japan. The effect of
drinking on road traffic accidents was evaluated by ecological study. Road traffic accidents were 15442.0 ± 14404.9
deaths due to road traffic accidents were 103.5 ± 57.5 and injured subjects due to road traffic accidents were 19068.3 ±
17433.6 in 2010 in all 47 prefectures of Japan. Drinking habits was significantly and negatively correlated with injured
subjects due to road traffic accidents. However, road traffic accidents due to drinking was positively correlated with
injured subjects due to road traffic accidents (r = 0.492, p = 0.0004). In conclusion, drinking habits and road traffic ac-
cidents due to drunk driving were closely linked to injured subjects due to road traffic accidents in Japan.
Keywords: Road Traffic Accidents; Drinking Habits; Ecological Study; Japan
1. Introduction
In many countries as well as Japan, automobiles are nec-
essary. Road traffic accidents and its relation to death
and injury have still been public health challenge in Ja-
pan. For example, a total of 725,773 road traffic acci-
dents and 4363 deaths was reported by Ministry of In-
ternal Affairs and Communications, Japan [1]. Therefore,
reducing road traffic accidents and its related death and
injury is urgently required in Japan.
Many factors were thought to be associated with road
traffic accidents. Number of cars in Japan has dramati-
cally increased last 30 years [2]. Drinking habits and
drunk driving are thought to be closely linked to road
traffic accidents and many health related problems, and
men with drinking habits are reported to be 35.4% in
Japan [3]. However, there are differences of drinking
habits among 47 prefectures in Japan [4]. In addition, the
effect of drinking habits on road traffic accidents still
remains to be investigated in the Japanese.
The aim of this study was to explore the link between
road traffic accidents and drinking habits in the Japanese
by ecological study.
2. Data Collection and Analysis
2.1. Road Traffic Accidents
Data on road traffic accidents in 2010 in all 47 prefectures
of Japan i.e. number of traffic accidents, number of death
due to road traffic accidents, number of injured subjects
due to road traffic accidents, number of death (per ten
thousand cars and per a hundred thousand people) and
number of injured subjects (per ten thousand cars and per
a hundred thousand people) were obtained from official
web site of Ministry of Internal Affairs and Communica-
tions, Japan [1]. Road traffic accidents due to drinking
(per a hundred thousand people with driving license) in
2011 were also employed from The General Insurance
Association of Japan [5]. These data were officially and
accurately obtained from all 47 prefectures of Japan.
2.2. Drinking Habits
Data on drinking habits in men in all 47 prefectures of
Japan were obtained from Ministry of Health Labour and
Welfare, Japan [4]. These data were also officially and
obtained by appropriate sampling. In addition, data were
C
opyright © 2013 SciRes. JTTs

N. MIYATAKE ET AL. 191
averaged from 2008 to 2012, and adjusted for age [4].
Men with over the alcohol level of 1 go (180 ml of Japa-
nese rice wine) per a day and 3 days per a week were
defined as having drinking habits. The effect of drinking
habits on road traffic accidents was evaluated by using
ecological study.
2.3. Statistical Analysis
A simple correlation analysis was used to test the sig-
nificance of the linear relationship among continuous
variables, and multiple regression analysis was also per-
formed to adjust parameters: p < 0.05 was considered to
be statistically significant.
3. Results
Profiles of all 47 prefectures of Japan were summarized
in Table 1. Road traffic accidents were 15442.0 ±
14404.9, death due to road traffic accidents were 103.5 ±
57.5 and injured subjects due to road traffic accidents
were 19068.3 ± 17433.6 in 2010 of Japan.
Drinking habits are well known to be one of major
cause of road traffic accidents. Therefore, we also inves-
tigated the relationships between road traffic accidents
parameters and drinking habits in men (Table 2). Drink-
ing habits in men were significantly and negatively cor-
related with injured subjects (per ten thousand cars and
per a hundred thousand people) due to road traffic acci-
dents (Figure 1). However, road traffic accidents due to
drinking (per a hundred thousand people with driving
license) were significantly and positively correlated with
injured subjects (per a hundred thousand people) due to
road traffic accidents (Table 3 and Figure 2). There was
not significant relationship between drinking habits in
men and road traffic accidents due to drinking (per a
hundred thousand people with driving license) (r =
−0.286). Finally, multiple regression analysis was also
performed to evaluate the effect of drinking habits in
men and road traffic accidents due to drinking (per a
hundred thousand people with driving license) on road
traffic accidents [injured subjects (per a hundred thou-
sand people) due to road traffic accidents = 1284.511 -
23.211 drinking habits in men +41.329 road traffic acci-
dents due to drinking (per a hundred thousand people
with driving license), r2 = 0.427, p < 0.0001].
4. Discussion
We firstly evaluated the link between road traffic acci-
dents and drinking in Japan by ecological study. Drink-
ing habits were closely associated with road traffic acci-
dents.
Drinking is a strong risk factor for traffic accident.
Matsushita reported that subjects with drunken driving
experience were to be 30% in men and 8% in women in
Table 1. Profiles of all 47 prefectures of Japan.
Mean ± SD MinimumMaximum
Prefectures 47
Road traffic accidents15442.0 ± 14404.9 181.2 55014
Death due to road traffic
accidents 103.5 ± 57.5 31 215
Injured subjects due to
road traffic accidents 19068.3 ± 17433.6 2261 62836
Death (per ten thousand
cars) 0.6 ± 0.1 0.4 0.8
Injured subjects (per ten
thousand cars) 91.3 ± 31.4 37.2 162.1
Death (per a hundred
thousand people) 4.8 ± 1.4 1.7 7.3
Injured subjects (per a
hundred thousand
people)
728.3 ± 263.0 314.9 1454.3
Drink habits (men) (%)36.4 ± 5.1 28.6 51.6
Road traffic accidents
due to drinking (per a
hundred thousand people
with driving license)
7.0 ± 2.3 3.2 14.0
Table 2. Simple correlation analysis between road traffic
accidents and drinking habits (men).
r p
Death (per ten
thousand cars) 0.010 0.9457
Injured subjects (per
ten thousand cars) −0.516 0.0002
Death (per a hundred
thousand people) −0.044 0.7674
Injured subjects (per
a hundred thousand
people)
−0.553 <0.0001
Table 3. Simple correlation analysis between road traffic
accidents and road traffic accidents due to drinking (per a
hundred thousand people with driving lic e nse ).
r p
Death (per ten
thousand cars) 0.127 0.3937
Injured subjects (per
ten thousand cars) 0.256 0.0823
Death (per a hundred
thousand people) 0.276 0.0602
Injured subjects (per
a hundred thousand
people)
0.492 0.0004

N. MIYATAKE ET AL. 192
20
40
60
80
100
120
140
160
180
Injured subjects (/ten thousand cars)
27.5 30 32.5 35 37.5 40 42.5 45 47.5 50 52.5
Drinking habits (men) ％
200
400
600
800
1000
1200
1400
1600
Injured subjects (/a hundred thousand people)
27.5 30 32.535 37.5 40 42.5 45 47.5 50 52.5
r=-0.516
p=0.0002
r=-0.553
p<0.0001
Drinking habits (men) ％
Figure 1. Simple correlation analysis between injured subjects (per ten thousand cars and per a hundred thousand people)
and drinking habits (%) in men in all 47 prefectures of Japan. r: correlatio n coefficient, p: p valu e.
20
40
60
80
100
120
140
160
180
2468 10 12 14 16
Road traffic accidents due to drinking
(/a hundred thousand people with driving license)
200
400
600
800
1000
1200
1400
1600
2 4 6 810 12 14 16
r=0.256
p=0.0823 r=0.492
p=0.000 4
Injured subjects (/ten thousand cars)
Injured subjects (/a hundred thousand people)
Road traffic accidents due to drinking
(/a hundred thousand people with driving license)
Figure 2. Simple correlation analysis between injured subjects (per ten thousand cars and per a hundred thousand people)
and road traffic accidents due to dr inking (per a hundred thousand people with driving lic ense) in all 47 prefec tures of Japan.
r: correlation coefficient, p: p value.
Japan. In addition, men in their 40’s - 60’s and women in
their 30’s had higher drunk driving experience [6]. The
effect of drinking on driving factors i.e. reaction time,
tracking, attention, watching and driving skills were ob-
served at extremely low concentration of alcohol [7,8]. It
has been reported that most of the blood ethanol concen-
tration of the victims in case of fatal self crash injury by
drinking driving ranges between 1 - 2 mg/ml [9]. This
may be due to the impairment of coordination or move-
ment, and changes in processing information by alcohol.
Fujita et al. examined and decreased the number of
drunken driving accidents at Kagawa prefecture, after the
change in the Road Traffic Low, Japan [10]. We proved
the road traffic accidents due to drinking (per a hundred
people with driving license) were positively correlated
with injured subjects due to road traffic accidents. How-
ever, drinking habits were negatively correlated with in-
jured subjects due to road traffic accidents by ecological
study. According to the National Nutrition Survey in
Japan, The criterion of the prevalence of subjects with
drinking habits is thought to be comparatively strict [4].
Taken together, subjects with obvious higher drinking
habits may not drive. However, low concentration of
alcohol may induce traffic accidents due to drunken
driving. Therefore, it is reasonable that we need to deal
with drunk driving with low concentration of alcohol in
Japan.
Potential limitations still remain in this study. First, we
used an ecological study. The link between road traffic
accidents and drinking habits, which was noted in this
study, may not apply for the link among individuals. In
fact, Impinen et al. reported that social factors, such as
low level of education, unemployment, living and di-
vorce, were associated with drunken driving [11]. Second,
detailed daily and individual (i.e. age and sex) data of
road traffic accidents and drinking could not be obtained
and analyzed in this study. The third, we could not obtain
the data of drinking habits in women. Therefore, we
could not evaluate the link between road traffic accidents
and drinking as accurately as we wished. Further ongoing

N. MIYATAKE ET AL. 193
investigations are urgently required to prove such a link.
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