ITARDA 24th Work Shop Report

2021
24th Presentation Session for Traffic Accident Investigations, Analysis, and Research

Pedestrian Accident Analysis Focusing on Vehicle Evolution and Human Age—Taking Population Aging Into Account—
Kenji Kawaguchi
Senior Researcher, Research Division

1

ITARDA 24th Work Shop Report

1. Introduction
For the first time, a target for reducing serious injuriesa was set forth in the 11th Basic Plan for Traffic Safety
formulated in March 2021. The target set for serious injuries is 22,000 or less by 2025 which, when combined withthe target for fatalities of 2,000 or less, results in a combined target of 24,000 or less for fatal and serious injuries.
In 2020, the number of fatal and serious injuries was 30,613. Of these, 8,000 were suffered while walking, which
was higher than the 7,895 suffered while riding a vehicle and is the highest number in a single year. For thesereasons, this paper focused on fatal and serious injury accidents suffered by pedestrians. By looking at the trend in
numbers of pedestrian fatal and serious injuries involving small- and medium-sized passenger vehicles, althoughsome years show a slight fluctuation, it can be seen that these numbers are decreasing long-term and that frontal
impact crashes involving pedestrians are high in number (see Fig. 1).
In an attempt to reduce pedestrian accidents andperformance and the adoption of various types of
preventive safety systems are being promoted. For
example, in terms of crash safety performance, theJNCAP (Japan New Car Assessment Program),
which evaluates the safety performance of newvehicles, began evaluating pedestrian

Area of vehicle wherecrash occurred

Number of pedestrian fatalities
and serious injuries

injuries, both improvements in vehicle crash safety

OtherRearSide
Front

headYear

protection performance in 2003 and leg protection

Fig. 1. Trend in numbers of pedestrian fatal and serious injuries

performance from 2011 in an attempt to improve(involving small- and medium-sized passenger vehicles)

vehicle performance in these areas. JNCAP has
also made steps in terms of preventive safety, such as starting evaluations of damage mitigation brakes forpedestrians (daytime) from 2016. Although it is assumed that the effects of these improvements are included among
the reductions shown in Figure 1, the bars above the accident years show totals that combine those for both oldvehicles and new vehicles, preventing the effects of these enhancements from being clarified.
In this paper, vehicles were categorized by the year of full-model change (Mo.CY) and an attempt was made toquantitatively clarify whether numbers of pedestrian accidents are decreasing for newer vehicle groups.
Furthermore, remaining issues for the newest vehicle types were elaborated on by taking the ages of drivers andpedestrians into account.

a"Serious injury" refers to an injury requiring 30 or more days of treatment.
2ITARDA 24th Work Shop Report

2. Analysis subjects and evaluation indicators
2-1. Grouping of vehicle classes

Table 1. Vehicle classes

Automobile Manufacturers Association (JAMA) are
as shown in Table 1b. These are based on a list fromthe end of 2019 in which vehicles are classified as
belonging to one of three groups: small-sized

Small-sized passenger
vehicles

Vehicle classes as defined by the Japan

passenger vehicles (or K-cars), medium-sized sedantype passenger vehicles (total height of less thanClassDefinition

Small-sized sedan

Two- or three-box with overall height of 1,400 mm or more

Small-sized sports

Two- or three-box with overall height of less than 1,400 mm

Small-sized one-box

One-box

Small-sized SUV

Two-box with overall height of 1,600 mm or more
Minimum ground clearance of 180 mm or more

Sedan M1

Sedan three-box with overall height of 1,400-1,600 mm
Engine displacement of 2,000 cc or less or max. output of 120
kw or lessSedan M2

Sedan three-box with overall height of 1,400-1,600 mm
Engine displacement above 2,000 cc or max. output above 120kw

SUV

Two-box with overall height of 1,600 mm or more
Minimum ground clearance of 180 mm or more

Sedan S1

Sedan two-box with overall height of 1,400-1,600 mm
Engine displacement of 2,000 cc or less or max. output of 120
kw or less

Sedan S2

Sedan two-box with overall height of 1,400-1,600 mm
Engine displacement above 2,000 cc or max. output above 120kw

more).

2-2. Groupings by year of full-model change andnumber of vehicle registrations

Medium-sized passenger vehicles

1,600 mm), and SUVs (total height of 1,600 mm orGroupings by year of full-model change or year of
new model introduction (Mo.CY) were segmented
across three years (2003, 2011, and 2016) based on
the information explained in the previous section "1.

SportyTwo- or three-box with overall height of less than 1,400 mm

Station wagon

Two-box with overall height of 1,400-1,600 mm, luggage room of 1 m2 or
more in principle

Tall wagon

Two-box with overall height of 1,600 mm or more

Minivan A

Two-box with overall height of 1,400-1,600 mm, three rows of seats

Minivan B

Two-box with overall height of 1,600 mm or more

One-box A

One-box with overall height of 1,600 mm or more

One-box B

One-box with overall height of 1,600 mm or more

Introduction".
The number of vehicle registrations was calculated by first obtaining information on the number of registeredvehicles by model name at the end of each year from (1) end of 2016 to (5) end of 2020 using a formula such asthat below.

Example:Number of vehicle registrations in 2017 = (end of 2016 +end of 2017)/2

Total number of vehicle registrations for 4 years = 2017 + 2018 + 2019 + 2020 (number of vehicle registrations
in each year)
Medium-sized
passenger vehicles
普通乗⽤
Small-sized passenger
軽乗⽤
vehiclesBy calculating in this manner, the total
number of vehicles of a particular model

セダン系Sedan
Total number of

Total number of

No. ofNo. of
⾞種数
⾞種数
Mo.C Year vehicle
registered vehicles
types 登録台数合計
types 登録台数合計
registered vehicles vehicle

SUV系

SUV
Total number of

No. of
⾞種数
registered vehicles
vehicletypes 登録台数合計

2000-2002

126,273,131

52

7,870,861

348,306,732

2003-201047 36,455,16499

36,032,654

65

27,724,360

period was obtained. Table 2 shows a

2011-2015

38 29,783,397

61

23,646,674

37

15,962,985

summary for the total number of vehicle

2016-201920

4,981,993

39

3,531,140

25

4,552,585

117 77,493,684

251

71,081,328

161

56,546,660

name (by Mo.CY) owned over a four-year

types and total number of registeredvehicles for each group.

b

合計
Total

Table 2. Number of vehicle types in each group and total number ofvehicle registrations(for 4 years from 2017 to 2020)

Although each class has its own definition, the class applied by the automobile manufacturer is ultimately
prioritized when determining individual vehicle types.
3

ITARDA 24th Work Shop Report

3. Analysis of reductions in pedestrian fatal and serious injury accidents due to vehicle evolution
3-1. Accident data
Accident data subjected to analysis is as follows:
Type of accident: Pedestrian accidents
Area of vehicle where crash occurred: Front (front + right-front + left-front)
Accident years: 2017 to 2020 (4 years in total)
Here, the number of accidents in each group from Table 2 was totaled, divided by the number of registeredvehicles, and then analyzed by the indicator "per 10,000 registered vehicles".

3-2. Analysis results
Analysis results for small-sized passenger vehicles are shown in Figure 2. Using data for the same period overthe four years from 2017 to 2020, fatalities, fatal and serious injuries, and casualties (fatalities + serious injuries +slight injuries) were compared based on Mo.CY group. Fatalities are decreasing the newer the group, with a 55%
decrease being seen when comparing the periods 2000 to 2002 and 2016 to 2019. Although fatal and serious injuries
and casualties are not decreasing at the rate of fatalities, a 22% decrease in fatal and serious injuries and an 18%

Number of pedestrian casualties
per 10,000 registered vehicles

Number of pedestrian fatalities
per 10,000 registered vehicles

Number of pedestrian fatal and serious
injuries per 10,000 registered vehicles

decrease in casualties can be seen when comparing the periods 2011 to 2015 and 2016 to 2019.

Fatalities
Fatal and serious injuries
Casualties
Fig. 2. Number of people by degree of injury per 10,000 registered vehicles by Mo.CY for small-sized
passenger vehicles (or K-car) (2017 to 2020)

4. Issue analysis
4-1. Analysis items
In order to identify issues for which initiatives(1)Vehicle class/Mo.CY(2)Driver age

Vehicle evolution(4)Speed(5)Human factors

should be undertaken in the future, general trend
analysis was performed on the items shown in(3)Pedestrian age

Figure 3 and on the differences between Mo.CY
groups.

(6)Point of contact

Areas related topreventive safety

Areas related to crashsafety(7)Main site of injury
Person's age

Fig. 3. Overall view of analysis items

4

ITARDA 24th Work Shop Report

4-2. Changes in speeds and driver age groups
Figure 4 shows the number of pedestrian fatal and serious injuries in 2000 and 2020 distributed by danger
perception speed. Although the percentage of accidents in 2000 that occurred at 20 km/h or less was 34%, by 2020,
because of significant decreases in the number of accidents at medium and high speeds, the percentage of accidents
that occurred at 20 km/h had risen to 53%, indicating the increased importance of addressing low-speed accidents.
Also, as shown by the color-coded driver age groups in the graph, the percentage of drivers in the age groups of
24 and under and 25 to 34 had decreased significantly in 2020 compared to their relatively large percentage in 2000,
indicating that the number of pedestrian fatal and serious injuries caused by elderly drivers and occurring at lowspeeds is increasing.

Driver age
group

Number of pedestrian fatal and serious injuries

Number of pedestrian fatal and serious injuries

2000

75 and above
65-74
55-64
45-54
35-44
25-34
24 and under

Danger perception speed (km/h or less)

70 km/h or more

2020

Driver age
group

Large decrease at medium/high speeds

75 and above
65-74
55-64
45-54
35-44
25-34
24 and under

70 km/h or more
Danger perception speed (km/h or less)Fig. 4. Danger perception speed and driver age group in accidents resulting in pedestrian fatal and serious injuries(2000 and 2020) and caused by drivers of medium- and small-sized passenger vehicles

4-3. Reductions by Mo.CY by speed
Figure 5 shows numbers of pedestrian fatal and serious injuries compared by Mo.CY groups of small- andmedium-sized sedan-type passenger vehicles and distributed by speed, with the vertical axis representing thenumber of fatal and serious injuries per 100,000 registered vehicles. In the case of small-sized passenger vehicles,
although there was no decrease at speeds of 10 km/h or less, speeds above that showed a decreasing trend. In thecase of sedan-type vehicles, decreasing trends could be seen across all speed ranges. In both cases, there were a

Pedestrian fatal and serious injuries per
100,000 vehiclesPedestrian fatal and serious injuries per
100,000 vehicles

large number of pedestrian fatal and serious injuries at a speed of 20 km/h or less.

Danger perception speed (km/h or less)Danger perception speed (km/h or less)Small-sized passenger vehicles
Medium-sized sedan-type passenger vehicles
Fig. 5. Comparison of pedestrian fatal and serious injuries by Mo.CY by danger perception speed(totals for 2017 to 2020)

5ITARDA 24th Work Shop Report

4-4. Human factors
Figure 6 shows human factors in pedestrian fatal andHuman factor composition ratebreakdown, 31 of these, or roughly 70%, were caused

75 andabove

65-74

by drivers aged 75 and above. Looking at a detailed

55-64

there were 44 instances of operational errors committed

45-54high in the case of drivers aged 75 and above. In 2020,

Cognition

35-44

age groups, the percentage of operational errors wasJudgment

24 andundergroup. Although cognition errors were highest for all

Operation

25-34

serious injury accidents broken down by driver age

Driver age

by misapplication of the brake and accelerator pedals.

Fig. 6. Human errors in pedestrian fatal andserious injuries caused by drivers of medium- andsmall-sized passenger vehicles in 2020

4-5. Point of contact and injury site
Figure 7 shows rates of pedestrian fatal and serious
injuries by age group for vehicles with a Mo.CY between

Rate of fatal or serious
2016 to 2019 Mo.CY, Point of contact: Vehicle bodyinjury

Pedestrian

2016 and 2019. As shown in Figure 4, this shows that more

6 and underthan half of fatal and serious injury accidents occur at a7-12

danger perception speed of 20km/h or less. In the case of

13-24

small-sized and sedan-type passenger vehicles, it is starting

25-34

to be seen that more than 10% of fatal and serious injury
accidents involve pedestrians aged 55 and older, orpedestrians of 45 and older in the case of SUVs. Although

55-64
65-74
75-84
85 and above

and sedan-type passenger vehicles, it can be seen that theSUV

45-54

high, because the number of fatal and serious injuries is low

When analyzing injury sites, in the case of small-sizedSedan

35-44

the number of pedestrians aged 12 and under also appears
at 5 or less, it was not discussed here.

Small-sized

Fig. 7. Rates of pedestrian fatal and serious
injuries by age group in accidents that occurred
between 2017 and 2020
at a danger perception speed of 20 km/h or lesschest and abdomen were the main sites that suffered the most injuries among pedestrians aged 65 and older. In thecase of SUVs, pedestrians aged 45 to 54 also suffered serious injuries to the chest, back, and legs. For the elderly,
multiple cases were observed in which arms suffered the most serious injuries.
5. Summary
5-1. Findings(1) Through this research, it was confirmed that grouping vehicles by year of full-model change showed that thenewer the vehicle, the lower the number of pedestrian accidents.
(2) As for long-term changes, it was clarified that a high percentage of pedestrian fatal and serious injury
accidents are caused by elderly drivers, and that the high percentage of low-speed accidents was due todecreases in accidents occurring in the middle- and high-speed ranges.
(3) The percentage of pedestrian fatal and serious injuries caused due to operational errors committed by drivers
aged 75 and above was high, with accelerator and brake pedal misapplication making up a large percentage
6

ITARDA 24th Work Shop Reportof such errors.
(4) Serious injuries are even occurring at low speeds of 20 km/h or less, and middle-aged and elderly pedestrians
are at a particularly high risk.

5-2 Future issues for research
Future issues for research derived through this research are as follows:(1) Research aimed at low-speed pedestrian accident avoidance(2) Research on accident-avoidance support systems for elderly drivers(Ex.: Acceleration control devices for preventing pedal misapplication that also detect pedestrians)(3) Research to investigate the mechanism of serious injuries that occur to the chest, abdomen, back, and legs at
low speeds of 20 km/h or less, as well as research to determine whether countermeasures for such injuries
are possible<Sources>(1) 近藤直弥、2020 年、「軽乗⽤⾞の衝突被害軽減ブレーキ(AEB)の効果分析」、イタルダインフォメーション(No.133)

7