Analyse des Unfallgeschehens zwischen PKW und Fahrrädern ... ≈ 4.500 fatalities Japan: ≈ 850 fatalities Indonesia: ≈ 2.200 fatalities USA: ≈ 750 fatalities In many countries

BGS

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Analyse des Unfallgeschehens zwischen

PKW und Fahrrädern im Hinblick auf

passive Schutzmaßnahmen

Dipl.-Ing. Henrik LiersVerkehrsunfallforschung an der TU Dresden GmbH

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2 BGS© 2011 carhs.training gmbh / BGS Böhme & Gehring GmbH

Overview

Motivation

Accident scenario involving cyclists

Descriptive statistics of cyclist accidents in GIDAS

Injury causation of cyclists

Use and protection potential of cycle helmets

Conclusions

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Decreasing trend in fatalities both for pedestrians and cyclists

However, it seems

that efforts in the

field of pedestrian

safety have been

more effective in the

last decade (based

on the decrease of

fatalities)

Germany: Converging

numbers of pedestrian

and cyclist fatalities

Motivation

overall fatalities in Germany (2009): 4.152

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Motivation

Similarities between pedestrian and cyclist accidents:

• similar relevance within accident scenario

• comparable conflict situations / accident types

• similar impact kinematics (esp. in frontal collisions)

Differences:

• single accidents of cyclists

• use of helmets

• own velocity of the cyclist (much higher than the pedestrian ones)

• presence of a vehicle (influence of lighting, possible technical

deficiencies, braking behavior etc.)

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Cyclist accident scenario worldwide

Cyclist accidents claim for thousands of fatalities and millions of

slightly and seriously injured people worldwide

Especially in some Asian countries remarkable numbers of cyclist

fatalities can be found (official numbers are partially highly doubtful)

China: ≈ 9.200 fatalities Brazil: ≈ 1.600 fatalities

India: ≈ 4.500 fatalities Japan: ≈ 850 fatalities

Indonesia: ≈ 2.200 fatalities USA: ≈ 750 fatalities

In many countries an increase/stagnation of the VRU’s proportion in

fatalities may be expected due to the strong increase in motorization

source: WHO - GLOBAL STATUS REPORT ON ROAD SAFETY, 2009

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Cyclist accident scenario in Europe

Europe (2009): ca. 2.250 killed cyclists per year (≈ 6.700 pedestrians)

Most European countries: general decrease of cyclist fatalities over

the last years (but also stronger decrease of pedestrian fatalities)

NL: more (than twice as many) cyclist fatalities than pedestrian

fatalities (the only country in Europe)

In some other European countries (incl. Germany): similar numbers

of pedestrian and cyclist fatalities or at least converging curves

In few European countries: increasing fatality numbers

source: CARE (EU road accidents database)

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Cyclist accident scenario in Germany

Cyclist accidents: important role in the German accident scenario

Despite a large number of unreported cases (especially single

accidents with less severe injuries), cyclist accidents occur more

than twice as often as pedestrian accidents

On the one hand: less cyclist fatalities than pedestrian fatalities

On the other hand: overall socio-economic costs (personal damage*)

of cyclist accidents are 1,5 times higher than pedestrian accidents

Germany (2009) pedestrians cyclists factor

Accidents involving … 33.076 75.913 2,3

fatally injured persons 591 462 0,8

seriously injured persons 8.139 14.182 1,7slightly injured persons 23.508 61.153 2,6

*source: Socio-economic costs due to road traffic accidents in Germany, BASt, 2009

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Cyclist accident scenario in Germany

47% of cyclist fatalities

result from collisions

with passenger cars

(not only frontal impacts)

Every fourth fatally

injured cyclist dies in

a single accident

(no potential for any

passive safety measures

on vehicles)

Trucks still cause every

fifth cyclist fatality

source: DESTATIS, 2009, own calculation

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Aims of the study

Aims of the current study (on behalf of ACEA):

• Characterization / descriptive statistics of bicycle accidents

(focus on collisions with passenger cars, impacts on the front)

• Analyses on injury level

- injury severity

- affected body regions

- injury causation

- comparison of different AIS coding guides

• Analyses concerning the impact distribution

• Helmet use and estimation of the protective potential of helmets

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Dataset

Use of the GIDAS (German In-Depth Accident Study) database

Accidents investigated in Hanover and Dresden from 1999-2009

After weighting the data to the German national statistics, there are

2099 accidents available for the analysis

known MAIS & collision speed: 2526

reconstructed accidents involving injured cyclists: 4897

frontal impact on the M1/N1 vehicle: 2785

accidents/collisions with M1/N1 vehicles: 3411

100%

70%

57%

52%

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Collision speed (= speed of the car) vs. injury severity of the cyclist

• 1934 accidents w/ collision speeds ≤40 kph: 1,4 fatalities (0,07%)

• 165 accidents w/ collision speeds >40 kph: 6,7 fatalities (4,09%)

Descriptive statistics of bicycle accidents in GIDAS

2099 accidents

≤ 40 kph:

1934 accidents (92,1%)

> 40 kph:

165 accidents (7,9%)

injury severity

of the cyclists

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Injury severity (MAIS) of the cyclists:

• 4 out of 5 injured cyclists are MAIS1 injured

• proportion of MAIS2+ / MAIS3+ injured cyclists: 19,2% / 3,2%

66,9 MAIS3+ injured cyclists

(3,2%)

AIS1990 Rev. 1998

403,1 MAIS2+ injured cyclists

(19,2%)

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Target of most efforts in vehicle/road safety are seriously/fatally

respectively MAIS2+ injured persons

The present study also focuses on the 403,1 accidents with

MAIS2+ injured cyclists

• 134,7 slightly injured cyclists (hospitalisation < 24 hours)

• 260,3 seriously injured cyclists (hospitalisation > 24 hours)

• 8,1 fatally injured cyclists (died within 30 days after accident)

High numbers of slightly injured cyclists (according to the official

definition) with an MAIS2+ result from the use of the AIS1990

Revision 1998

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The vast majority of accidents between passenger cars and bicycles

(resulting in MAIS2+ injured cyclists) occur in urban areas

One fifth of the accidents happen during twilight or at night

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Crossings and T-junctions are the main accident locations of MAIS2+

injured cyclists, followed by straights

In every second accident no cycle way was available


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More than 80% of the cyclists have turning or crossing accidents

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The main type of accident (describing the general type of conflict)

again shows the large importance of crossing situations

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The most frequent accident types are crossing and turning situations

The majority of the initial situations are comparable to the

critical situations in frontal pedestrian accidents:

either perpendicular movement of the vehicles

or collision during turning

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Accident causation (main accident causes):

• The majority (62%) of the accidents are caused by the car

• “Ignoring the traffic sign ruling the right of way” is by far the most

frequent accident cause for both cars and bicycles

Contributing factors: • 4,4% of cases w/ intoxicated cyclist (alcohol)

• 7,8% of cases w/ technical deficiencies (cycle)

TOP5 of the main accident causes

Main accident causer = passenger car Main accident causer = bicycle

ignoring the traffic sign

ruling the right of way 46%

ignoring the traffic sign

ruling the right of way 34%

mistake during turning 20% mistake during the start in the traffic 14%

other mistakes of the driver 5% ignoring traffic lights (or police officer) 12%

mistake during the start in the traffic 5% use of the wrong (side of) road 10%

ignoring traffic lights (or police officer) 4% mistake during turning 9%

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Contrary to pedestrians bicycles have own velocities that can not be

disregarded (e.g. collision with standing passenger cars)

• Ø collision speed

(passenger car):

26,8 kph

(median 23 kph)

• Ø collision speed

(bicycle):

14,1 kph

(median 15kph)

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Personal data (MAIS2+ injured cyclists) – Gender & Age

• gender distribution: 58% male, 42% female

• contrary to pedestrians, the age of cyclists is more evenly

distributed (but less children up to 10 years)

age of the cyclists (grouped, in years)

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Personal data (MAIS2+ injured cyclists) – Body height

• remarkable proportions are only found above 150cm with an

average of 170,4cm

body height of the cyclists(grouped, in cm)

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Injury data – Injury severity (AIS)

• in total, all MAIS2+ injured cyclists suffered 1749 single injuries

• most of their injuries are slight injuries (AIS1)

AIS1990 Rev. 1998

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Injury data – Affected body regions


AIS 1+

n = 1749,3

AIS 2+

n = 684,9

AIS 3+

n = 147,5

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Injury data – Affected body regions

• all (AIS1+) injuries: lower extremities with largest proportion,

followed by upper extremities

• with increasing injury severity levels (AIS2+ AIS3+):

- the head is by far the most frequently injured body region

- the relevance of thorax increases substantially

- the portion of injuries on lower extremities remains nearly constant

- injuries on upper extremities and the face become less important

(there are hardly any AIS3+ injuries in these regions)


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Detailed investigations on the causation of injuries is a substantial

part of in-depth accident studies like GIDAS

The injury causing part is coded for every single injury (70.000 so far)

Various analyses on injury causation can be done, e.g.:

• estimation of the relevance of several vehicle parts

• influence of the secondary / ground impact

• observation of the development of particular injury causing parts

against the background of ongoing efforts in road/vehicle safety

Here: Analysis of injury causation for the three most relevant body

regions of cyclists (head/face, thorax, lower extremities)


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head/face injuries AIS1+

window frame / A-pillar 43,3

windscreen 131,5

bonnet 12,2

bonnet leading edge 0,5

fender 3,9

grill and headlamps --

bumper --

other veh. parts / front nfs. * 23,4

own bicycle / other / unknown ** 10,4

ground impact 378,9

total 604,1

head/face injuries AIS1+ AIS2+

window frame / A-pillar 43,3 28,9

windscreen 131,5 74,4

bonnet 12,2 6,6

bonnet leading edge 0,5 0,5

fender 3,9 1,6

grill and headlamps -- --

bumper -- --

other veh. parts / front nfs. * 23,4 9,5

own bicycle / other / unknown ** 10,4 0,5

ground impact 378,9 159,9

total 604,1 281,9

head/face injuries AIS1+ AIS2+ AIS3+

window frame / A-pillar 43,3 28,9 15,8

windscreen 131,5 74,4 21,9

bonnet 12,2 6,6 --

bonnet leading edge 0,5 0,5 --

fender 3,9 1,6 --

grill and headlamps -- -- --

bumper -- -- --

other veh. parts / front nfs. * 23,4 9,5 2,9

own bicycle / other / unknown ** 10,4 0,5 --

ground impact 378,9 159,9 25,0

total 604,1 281,9 65,6

Injury causing parts of head/face injuries

• with increasing injury severity (AIS1+ AIS2+ AIS3+):

- window frame & windscreen more important, BLE not relevant

- ground impact very important with decreasing proportions


* incl. mirrors, B-pillar, doors, wheels, roof, glass etc.

** incl. body motion, all parts of the bicycle etc.

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injuries on lower extremities AIS1+


windscreen 6,5

bonnet 22,7


fender 27,0

grill and headlamps 8,1

bumper 118,3



ground impact 210,1

total 493,1

Injury causing parts of injuries on lower extremities (incl. pelvis)

• mainly caused by the bumper (often the first contact point

between cyclist and car)

• relevance of the ground decreases slightly for higher AIS values




injuries on lower extremities AIS1+ AIS2+


windscreen 6,5 1,7

bonnet 22,7 5,9


fender 27,0 8,6

grill and headlamps 8,1 3,9

bumper 118,3 70,7


own bicycle / other / unknown ** 38,5 10,7


total 493,1 173,8

injuries on lower extremities AIS1+ AIS2+ AIS3+

window frame / A-pillar 1,4 0,5 --

windscreen 6,5 1,7 --

bonnet 22,7 5,9 1,1

bonnet leading edge 25,8 9,8 3,7

fender 27,0 8,6 0,9

grill and headlamps 8,1 3,9 0,5

bumper 118,3 70,7 14,1


own bicycle / other / unknown ** 38,5 10,7 --


total 493,1 173,8 31,3

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thorax injuries AIS1+


windscreen 20,1

bonnet 24,2


fender 2,9

grill and headlamps --

bumper --



ground impact 40,6

total 112,9

thorax injuries AIS1+ AIS2+


windscreen 20,1 10,3

bonnet 24,2 8,6


fender 2,9 1,5

grill and headlamps -- --

bumper -- --


own bicycle / other / unknown ** 6,5 --


total 112,9 45,1

Injury causing parts of thorax injuries

• mainly caused by the ground impact, followed by the windscreen,

window frame and the bonnet

• the BLE looses its relevance for AIS3+ thorax injuries




thorax injuries AIS1+ AIS2+ AIS3+

window frame / A-pillar 8,8 6,4 3,3

windscreen 20,1 10,3 7,4

bonnet 24,2 8,6 5,4

bonnet leading edge 4,1 4,1 0,6

fender 2,9 1,5 1,5

grill and headlamps -- -- --

bumper -- -- --


own bicycle / other / unknown ** 6,5 -- --


total 112,9 45,1 28,8

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Analysis of the helmet usage of all cyclists in GIDAS

• generally: low helmet usage rates (slowly increasing over time)

• comparable rates in GIDAS (only accidents with injuries) and

normal traffic situations (e.g. BASt helmet use surveys)

Analyses on cycle helmets

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• helmet usage rate differs substantially with the cyclist’s age


average = 9,1%

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• gender distribution (all age groups, n = 5.296)

- male: 11,5%

- female: 5,2%

• gender distribution (≥ 16 years, n = 4.481 )

- male: 10,5%

- female: 3,7%

• gender distribution (≥ 50 years, n = 1.587)

- male: 8,4%

- female: 1,7%


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Estimation of the protective potential of cycle helmets

1st step: Comparison of cyclist accidents with and without helmet use

(to ensure that the general accident scenarios are comparable)

• Cyclists wearing helmets are appr. 8 years younger on average

• Cyclists with helmets are approximately 3 kph faster on average

• The collision speeds of the cars are similar

Accident situations w/ and w/o helmets are pretty comparable


average …accidents with

helmet use (n=171,5) no helmet use (n=1756,0)

… collision speed (car) 19,2 kph 20,1 kph

… collision speed (bicycle) 16,3 kph 13,5 kph

… cyclist age 30,7 yrs 38,4 yrs

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Expected benefit of helmets especially for the head Comparison of

the injury severity of the AIS region head (all cyclists in GIDAS)

• remarkable changes

of the injury severity

• no AIS4+ injuries are

found in accidents

with helmets

- AIS4: -0,54%

- AIS5: -0,17%

- AIS6: -0,05%

• proportion of cyclists

without head injuries

increases by 10,8%


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Conclusions I

Cyclists play an important role in traffic accidents worldwide

Germany: cyclist fatalities converge to pedestrian fatalities; higher

numbers of slightly and seriously injured cyclists than pedestrians

Accidents with passenger cars are the main reasons for cyclist

fatalities (47%) in Germany, followed by single accidents (23%)

Due to higher own velocities and occurrence of single accidents:

“ground line” of cyclist casualties not addressable (by vehicle safety)

80% of collisions with passenger cars are frontal impacts

More than 90% of these accidents happen at collision speeds ≤ 40 kph

Every 5th cyclist at least MAIS2+ injured, every 30th MAIS3+ injured

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Conclusions II

In general, severe cyclist accidents (MAIS2+) in GIDAS occurred:

• in urban areas

• during daytime

• in crossing / turning situations

• at crossings and junction

Approximately two thirds of frontal car-to-cycle accidents are caused

by the passenger car and mostly due to the violation of right of way

There are typical injury causing parts for every body region:

• head/face: windscreen, window frame, ground impact

• thorax: windscreen, bonnet, ground impact

• lower extremities: bumper, ground impact

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Conclusions III

The head is the most frequently injured body region of MAIS2+

injured cyclists, followed by the lower extremities and the thorax

The ground impact plays an important role (especially in single

accidents and in collisions with (nearly) standing passenger cars)

The use of cycle helmets is still not very usual in Germany

Helmet usage rates strongly depend on the age and the gender

Using a helmet can both protect the head from suffering very severe

injuries and increase the number of cyclists without head injuries

Out of the study’s results, it is recommended to enforce:

• helmet use • prevention measures

• driving abilities • primary & secondary safety measures

Documents

Analyse des Unfallgeschehens zwischen PKW und Fahrrädern ... ≈ 4.500 fatalities Japan: ≈ 850 fatalities Indonesia: ≈ 2.200 fatalities USA: ≈ 750 fatalities In many countries