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ITARDA INFORMATION
交通事故分析レポートlSpeciafeatureNo.103

Pedestrian Crashes on Expressways~No way! There canʼt be pedestrians in a place like this! ~Person-vehicle accidents on expressway lanes and shoulders (2003-2012)

200
180

No. of Accidents

160

191

184

140

143

120
100
80
60
40
20
0

Slightinjuries

Serious
injuries

1 Introduction....................................................P2
2 Traffic accidents on expressways..................P2
3 Frequently-occurring accident types .............P3
4 Case example of person-vehicle accidents
on expressways.............................................P4
5 Accidents that lead to fatalities more often....P4
6 Characteristics of person-vehicle accidents ..P5
7 Conclusion.....................................................P8

Fatalities

lSpeciafeaturePedestrian Crashes on Expressways~No way! There can’t be pedestrians in a place like this! ~1 Introduction
A thoroughgoing expressway network enhances economic activities of man and material and helps expanding thesphere of action of man. However, the development of expressways may bring unforeseen problems along with theincrease in its users. Last year, there was an unfortunate incident where a famous comedian, who got out of his car
after it was involved in a single-vehicle accident on the expressway, was run over by a following car. Stopping or
parking of vehicles and pedestrians are prohibited on expressways so as to ensure a safe and fast riding experience.
Nevertheless, we may end up in a situation where we may have to step out of our vehicles on to the expressway
lanes or shoulders if any problem occurs during the drive. Table 1 below shows the top ten reasons because ofwhich assistance of JAF Road Service was sought on expressways in 2012. Every year, more than 0.1 million casesof vehicle breakdown or accidents are reported for assistance. In this issue we shall focus on the secondary
pedestrian crashes with vehicles that are considered to occur following such breakdowns or accidents of vehicles.

Table 1 List of rescue requests to JAF Road Service on expressways in 2012 (4-wheeled vehicles)
Rank

Description of rescue requests

No. of requests

Composition ratio (%)

1

Tire-related problems (flat tires/explosion/low air pressure)

31,70731.49

2

Out of fuel14,116

14.02

3

Accidents

9,459

9.39

4

Over-discharged battery

7,129

7.08

5

Generator/ battery charging circuit

2,161

2.15

6

Locking of key inside the vehicle

1,898

1.89

7

Automatic transmission

1,383

1.37

8

Auxiliary drive belt

1,217

1.21

9

Damaged/deteriorated battery

1,157

1.15

10

Out of engine oil/replenishment

1,124

1.12

Total of requests other than the above

29,335

29.14

Total

100,686

100.00Source: Excerpt from JAF webpage (http://www.jaf.or.jp/rservice/data/index.htm)

2 Traffic accidents on expressways
Let us look at the transition in the number of traffic accidents and fatal accidents on expressways*1 (Refer Fig. 1).
By and large, the following trend prevails.
1) Both traffic and fatal accidents on expressways are progressively on the decline.
2) However, over the recent years, there is an increase in the number and rate of fatal accidents.
3) Roughly 11,000 cases of traffic accidents and 200 cases of fatal accidents are reported every year.
Data compiled by the National Police Agency in their report “Traffic accident situation in 2012” reveals that theoccurrence rate of fatal accidents on national roads is 0.89% whereas it is 1.73% (in 2012) on expressways
indicating that once an accident happens on the expressway, the situation is about 2-fold critical as compared tothe one on the national road.
*1 Expressways include national expressways and the highways for exclusive use by motorized vehicles like metropolitan expressways and Hanshin expressway.

ITARDA INFORMATION no.103

400

No. of traffic accidents

20,000No. of fatal accidents

No. of traffic accidents

15,000300

10,000

200

5,000

100

Rate of fatal accidents
0

0
2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

Rate of fatal accidents (x100)

206

219

199

181

170

175

161

146

137

162

173

No. of traffic accidents

14,083 13,993 13,799 13,776 13,803 12,675 10,970 11,114 12,202 11,710 11,299

No. of fatal accidents

290

307

274

249

234

222

177

162

167

190

No. of fatal accidents andRate of fatal accidents (x 100)

ITARDA INFORMATION no.103

196

Fig.1 Transition in numbers of Traffic and Fatal accidents and Rate of fatal accidents on Expressways (2002-2012)
Rate of fatal accidents = (No. of fatal accidents)/ (No. of traffic accidents) x 100 x100

Rate of fatal accidents is scaled 100 times to suit the plotting of graph

3 Frequently-occurring accident types
Let us observe the type of accidents that occur frequently as well as the number of fatal accidents. Fig.2 shows thecomposition of traffic accidents (top) and fatal accidents (bottom) that occurred on expressways from 2003 through2012 by type of accidents.
Sixty-seven percent of accidents on expressways were multiple-vehicle rear-end-collisions. The reasons for suchhigh occurrence of collisions were longer stopping time and distance as compared to general roads and theabsence of intersections and traffic signals which may tempt the drivers into aimless driving. Following the lead are
the single-vehicle collisions, multiple-vehicle collisions (crashes or contacts) and other multiple-vehicle collisions
with each accounting for about 10%.
Whereas the composition of fatal accidents differs considerably with single-vehicle collisions leading the lot,followed by multiple-vehicle rear-end-collisions and multiple-vehicle collisions (crashes or contacts) in that order.
Here, attention is paid to the person-vehicle accidents that occurred occasionally after the “single-vehicle andmultiple-vehicle collisions.” Though their occurrence is very low at 1.1%, they account for roughly 10% of the fatal
accidents.

Multiple-vehicle
collisions(rear-end-collisions)

Multiple-vehicle collisions(crashes or contacts)

83,813

No. of traffic accidents

No. of fatal accidents

0％Multiple-vehicle
collisions (others)

573

10％

301

20％

30％

Single-vehicle
collisions

11,355 11,919

82

40％

Person-vehicle
accidents

212

1010

50％

60％

70％

1,355

16,899

80％

90％

100％

Composition ratio

Fig.2 Composition ratio of Traffic accidents and Fatal accidents on expressways
by type of accident (2003-2012; n=125341)
Multiple-vehicle collision (rear-end-collisions): When both vehicles are facing in the same direction and the front of the following vehicle hits the back of the preceding vehicle
when the latter is on the move, parked or stopped.
Multiple-vehicle collisions (crashes or contacts): Collisions other than rear-end ones such as when the vehicle crashes into or comes in contact with the front or side of arunning vehicle or an entering/exiting vehicle.
Multiple-vehicle collisions (others): Accidents involving multiple vehicles other than the rear-end-collisions, crashes or contact accidents.
(Example, hit by the following car soon after the vehicle on front had proceeded from its stopped position for changing the lane, or crash at service area etc.)

ITARDA INFORMATION no.103lSpeciafeaturePedestrian Crashes on Expressways~No way! There can’t be pedestrians in a place like this! ~4 Case example of person-vehicle accidents on expressways
Explained below is a case example of person-vehicle accident taken from our In-depth case studies.
It was still early in the morning on a clear winter Sunday and the silhouettes of surrounding objects were only dimly
visible. Mr.A, in his fifties, was driving a medium-sized truck on the lane-1 of a driveway with 3-lanes on one-side,with the headlights on. A little before the accident, Mr.B, in his twenties, had somehow pulled over his passenger
car onto the road shoulder when his car tire was punctured and he could not continue driving any further. However,a part of his car was still protruding into the lane-1. Mr.C, also in his twenties and travelling with Mr.B had alighted
the car and was helping the latter fix the punctured tire when Mr.A’s truck collided into the stopped car. Both Mr.B
and Mr.C were run over along with the car; Mr.B was crushed under the truck and died on the spot, whereas Mr.C
sustained serious injuries.
This case exemplifies a typical person-vehicle secondary crash where the occupant had alighted the vehicle after it
was broken down and was hit by an approaching vehicle. The lanes and shoulders of expressways are enclosed
by fences so that the pedestrians ought not enter. For that reason the person-vehicle accidents occurring on
general roads can be attributed to different circumstances whereas on expressways such accidents are secondary
in nature characterized by a prior incidence of a vehicle breakdown, primary accident or any other kind of traffic
accident. (Nevertheless, person-vehicle accidents occurring on the service areas or parking lots of expressways
are mostly similar in situation to those happening on general roads and parking lots.)

Median

B1
A1
A2

B2
C1

C2

Fig.3 Example of a secondary accident situation on the expressway

5 Accidents that lead to fatalities more often
20.00

15.65
15.00

10.00
5.98
5.00
2.65

1.74
0.69

0.68

Overall average

Person-vehicle

Single-vehicle

multiple-vehicle(Others)

Multiple-vehicle(crashes orcontacts)

0.00
Multiple-vehicle(rear-end-collision)

Rate of fatal accidents (%)

Comparing person-vehicle accidents that areconsidered mostly secondary in nature with othertypes of accidents may seem like an apple toorange comparison; nevertheless, the rate of fatal
accidents of other types is compared as under.
Fig.4 shows the rate of fatal accidents by type of
accidents based on the numbers of traffic
accidents and fatal accidents given in Fig.2.
Apparently, rate of person-vehicle fatal accidents(15.65%) is significantly higher as compared toother types of accidents and is nine times more
likely to occur than the overall average ofaccidents (1.74%) occurring on expressways. In
other words, one among every six person-vehicle
accidents occurring on expressways leads tofatalities.

Fig.4 Rate of fatal accidents on expressways
by type of accidents (2003-2012)
ITARDA INFORMATION no.103

ITARDA INFORMATION no.103

6 Characteristics of person-vehicle accidents
Let us now observe the characteristics of person-vehicle accidents occurring on expressways.

■Place of occurrence
Fig. 5 shows the place where person-vehicle accidents occurred by the injury level of the victim in terms of thecomposition ratio of road segments.
Accidents on service areas and parking lots led mostly to slight injuries whereas fatal accidents occurred more on
the expressway lanes or shoulders accounting for nearly 90%. Furthermore, the number of person-vehicle
accidents at lanes and shoulders combined, resulted in more fatal accidents (191 cases) than slight injured
accidents (184 cases) and one in every 2.7 accidents (518/191 cases) is fatal.
Shoulder

Lane

Slight injuries
(878)

154

Serious injuries
(265)

30

Ramp/Toll gate

100

594

125

Fatalities
(212)

SA/PA

18

35

165

0％

20％

40％

87

26

60％

14

7

80％

100％

Composition ratio
Total 518 cases
Fig.5 Person-vehicle accidents on expressways by injury leveland by composition ratio of road segments (2003-2012)<Road segments>
Lane: Driving lane, passing lane, accelerating lane, decelerating lane and slow-traffic lane
Shoulder: Area starting from the outer lane of the road up to the edge of the road marked by safety barrier, guard rail etc.
Ramp/Toll gate: Slip roads for entry and exit, junctions, toll gate, others
SA/PA: Service area, parking area

■SpeedFig. 6 compares the composition rate of danger perception speed*2 in person-vehicle accidents occurring at“expressways” and “other roads.” On expressways accidents mainly occur at the danger perception speed of
10km/h and under accounting for about half of the total and the location happened to be service areas and parking
areas. This is because the chances of encountering pedestrians here are more, as is the case with general parking
lots. Moreover, accidents peak at around 80~100km/h on other roads, where they are most unlikely to happen.
Fig. 7 shows the correlation between danger perception speed and fatality rate in person-vehicle accidents. Be iton expressways or other roads, the fatality rate projects a similar trend. Fatality rate grows in proportion with thedanger perception speed and is 50% at the speed of 80km/h.
Fig.8 shows the distribution of danger perception speed in person-vehicle fatal accidents. As compared to otherroads, the danger perception speed is higher by 40km/h in expressways at around 90km/h. Therefore it is essential
to always keep in mind while driving on expressways that we are at a high fatal risk.
*2 Danger perception speed: The speed of the vehicle when we perceive the other party as a danger.

ITARDA INFORMATION no.103

Pedestrian Crashes on Expressways~No way! There can’t be pedestrians in a place like this! ~Expressways
Other roads

Accidents at lanes
and shoulders

Expressways
Other roads

Expressways

35.0

Other roads

30.0
25.0
20.0
15.0

40km/h

10.0
5.0

〜140

〜120

〜100

〜90

〜80

〜70

〜60

〜50

〜40

〜30

〜20

0.0

〜10

〜140

〜120

〜100

〜90

〜80

〜70

〜60

〜50

〜40

〜30

〜20

70
60
50
40
30
20
10
0

40.0

〜10

〜140

〜120

〜100

〜90

〜80

〜70

〜60

〜50

〜40

〜30

〜20

〜10

35.0
30.0
25.0
20.0
15.0
10.0
5.0
0.0

100
90
80

Accidents at SA/PA

Composition rate (%)

50.0
45.0
40.0

Fatality rate (%)

Composition rate (%)

lSpeciafeatureDanger perception speed (km/h)

Danger perception speed (km/h)

Danger perception speed (km/h)

Fig.6 Danger perception speed
in person-vehicle accidents(Primary and secondary vehicles,
2003-2012)

Fig.7 Danger perception speed
and fatality rate ofperson-vehicle accidents(Primary and secondary
vehicles, 2003-2012)

Fig.8 Danger perception speed
in person-vehicle fatal accidents(Primary and secondary
vehicles, 2003-2012)■Radius of curvature of expressways
Do the curved lanes and tunnels in expressways have any influence on person-vehicle accidents? In Fig.9
person-vehicle accidents are distributed by the injury levels, and then plotted based on the radius of curvature of
curved roads. The legend “not applicable” refers to places like service and parking areas where the radius is notclear. Apparently, 80% of fatal accidents occur on straight roads (139 cases) and on roads with 1000m or moreradii (31 cases) with unobstructed view. Let us now observe the case of tunnels where the view becomes
obstructed if the roads there are curved (Fig. 10). No accidents have occurred in tunnels with roads having small
radius of curvature. It can be said that person-vehicle fatal accidents occur more frequently in places withunobstructed view.
Below 500m

Slight injuries 13 17
11(878)
Serious injuries 13 17(265)
Fatalities
(212)

6

500-1000m

1000m or over

Straight roads

168

667

13

116

114

31

19

0％

Not applicable

139

20％

40％

17

60％

80％

100％

Fig.9 Composition ratio of injury levels of person-vehicle accidents by radius of curved expressway segments (2003-2012)

No. of fatal accidents

160
140

Other than tunnels

120
100
80

Tunnels

60
40
20
0

Below
500m

500-1000m

1000m
or over

Straight roads

Not applicable

Tunnels

0

0

4

0

Other than tunnels

6

19

27

5
134

17

Fig.10 Comparison of fatal accidents in tunnels and other than tunnels by radius (2003-2012)
ITARDA INFORMATION no.103

ITARDA INFORMATION no.103■Human factors
Fig.11 and Fig.12 shows respectively the influence of vehicle drivers and pedestrians in person-vehicle accidents.
More than 85% (180/208) of drivers failed to notice their front involving in aimless or distracted driving, thus unable
to detect pedestrians on time which resulted in accidents. In other words, since the view on expressways is
unobstructed, many drivers were complacent that would detect any pedestrians, but rather failed to notice one. In
places like expressways where there is a tendency of oversight, devices aiding the recognition of pedestrians suchas pedestrian detection system, and the deceleration or stopping of vehicles or avoidance of pedestrians can bequite reassuring. On the other hand, some pedestrians are also at fault because they step out of their vehicles
assuming that the following vehicle will either give way or stop, giving them priority just like in general roads. It
appears that together with the emergence of more and more expressway users, there are pedestrians who are notfully aware of the difference between expressways and general roads. The above-mentioned factor is only
validated by fellow passengers or witnesses or for that matter the driver of the other vehicle as all the pedestrians
in question have died in those accidents.

No. of drivers
0

50

100

Failure to notice front(intrinsic)

     
Preoccupied/aimless driving (63)Failure to notice front(extrinsic)

Dropped an object /tried
to pick up an object (6)Distracted driving: Focusing on
co-passengers or objects (2)Operating stereo or cell-phone (2)Operating/viewing TV or navigation
system (1)Reading magazine or map (2)Distracted driving: searching forroutes/signposts (4)Distracted driving: observing sceneries
or local features (3)Distracted driving: viewing othervehicles or pedestrians (31)Viewing rear/side view mirrors (7)Other distracted driving (21)Failure to check safety
Failure to notice movement

Delay indetection (180)

Judgment
error (24)Lack of anticipation

Traffic environment
Driving operation
error (4)Inapt driving operation

n=208

Fig.11 Human factors of drivers (primary and secondary parties) involvedin person-vehicle fatal accidents (2003-2012)
No. of pedestrians
0

20

40

60

80

Inattentive guardians

Delay in detection

Engrossed in work (5)Preoccupied aimless walking (3)Failure to check safety (17)Insufficient safety check (7)Judgment error
Poor health condition

Human factor unknown
n=212
No human factor

Error in judging the speed ofincoming vehicle (5)Assumed that the other party willobserve rules (4)Assumed that the other party will
give way or stop (12)Wanted to avoid otheraccident/danger (2)Others (33)

Fig.12 Human factors of pedestrians (primary and secondary parties)
who died in person-vehicle accidents (2003-2012)
ITARDA INFORMATION no.103

1. One out of every six person-vehicle accidents is fatal, while one out of every 2.7 such
accidents occurring on road shoulders or lanes is fatal.
2. Person-vehicle fatal accidents occur more on straight roads with unobstructed view.
3. “Delay in detection” resulting from human factors like “distracted” or “aimless” driving cause
majority of the drivers to be involved in person-vehicle accidents.
4. Human factors of pedestrians mainly include “delay in detection” rooted in complacency
such as “failure to check safety assuming that no vehicle is approaching” and “judgment
error” such as “the vehicle will avoid me” and “the vehicle will come to a stop.”■Ways to prevent person-vehicle accidents on expressways
1.

2.

3.

5.

(Makoto Shiota)

道 路 交 通 法の定める「 交 通 事 故 調 査 分 析 センター 」の 指 定を国 家 公 安 委員会 から受 けた 調 査 研 究 機 関であり、 交通 事 故 の 防 止と被 害 の 軽 減 の た め の交通事故の調査分析を行っています。

公益財団法人 交通事故総合分析センター
お問合せ先

旧住所（平成25年12月13日迄）ITARDA INFORMATION no.103●ウェブサイト http://www.itarda.or.jp/●Eメール koho@itarda.or.jp（新住所）〒101-0064
東京都千代田区猿楽町2-7-8 住友水道橋ビル8階
TEL 03-5577-3977(代表) FAX 03-5577-3980

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その後平成２４年（２０１２年）
４月に公益財団法人に移行しました。我が国で唯一

No.103

公益財団法人 交通事故総合分析センター〒101 0064 東 京 都 千 代 田 区 猿 楽 町 ２ ７ ８

4.

When you see a stopped vehicle while driving, anticipate the presence of pedestrians
nearby and exercise extra caution. Be fully prepared to tackle any probable danger byobserving the surroundings carefully, shifting your foot from accelerator to brake etc.
Presence of pedestrians on shoulders and lanes is an abnormal situation. Nevertheless,drivers are expected to continuously pay attention to their front for any humans or objects.
So keep ample distance with vehicles and be flexible in the vehicle operation to cope with
contingencies.
When stopping your vehicle on shoulders or lanes is unavoidable owing to an accident or
break down, it is essential to be fully aware to prevent secondary accidents. Alert theapproaching vehicle using smoke candles or warning triangles and quickly retreat to safety
beyond the guard rail etc. along with fellow passengers and thus be prepared for any
probable collision.
It is equally important to prevent vehicle breakdowns while driving. Always perform vehicle
inspection on routine basis especially before driving on expressways.
Technical development and dissemination of recognition devices are preferred which assist
the drivers in detecting pedestrians and decelerate, stop or avoide their vehicles
automatically when there is heightened danger of collision during high-speed driving.

ITARDA INFORMATION■Characteristics of person-vehicle accidents on expressways

交通事故分析レポート

7 Conclusion