INJURY EVENTS AMONG BUS AND COACH OCCUPANTS

U. BJÖRNSTIG, P. ALBERTSSON, J. BJÖRNSTIG, P-O BYLUND, T. FALKMER, J. PETZÄLL

INJURY EVENTS AMONG BUS AND COACH OCCUPANTS– Non-crash Injuries as Important as Crash Injuries –Ulf BJÖRNSTIG

Pontus ALBERTSSON

Johanna BJÖRNSTIG

Department of Surgical and Perioperative Sciences
Division of Surgery, Umeå University
Umeå, Sweden

Department of Surgical and Perioperative Sciences
Division of Surgery, Umeå University
Umeå, SwedenUmeå Accident Analysis Group
University HospitalUmeå, Sweden

P-O BYLUND

Torbjörn FALKMERJan PETZÄLL

Umeå Accident Analysis Group
University HospitalUmeå, Sweden

Rehabilitation Medicine
Department of Neuroscience and Locomotion
INR, Faculty of Health Sciences
Linköping University, Linköping, Sweden

Swedish National Road Administration
Borlänge, Sweden(Received January 13, 2005)

A ten year complete data set from the health sector, comprising 284 injured bus and coach occupants from a well defined area, was analyzed.
The annual injury incidence was 2 per 10,000 inhabitants, 3/4 were women. In non-crash incidents, 54% were injured; 2/3 while alighting from a bus orcoach. In crashes, 46% were injured; 2/3 in collisions with other vehicles and 1/3 in single vehicle crashes. During October-March, 3/4 were injured.
In two single vehicle mass casualty crashes in slippery road conditions, high built coaches were hit by so high cross wind forces that they were
blown off the road. This crash mechanism has received little attention earlier. Of those injured in collisions with other vehicles, 78% were injured incollisions with other heavy vehicles. Slippery conditions contributed to half of the alighting injuries. The proportion of moderate or more serious injuries (MAIS 2+) was highest in single vehicle crashes (48%) and in alighting and boarding (43%) incidents, and was lowest (5%) in collisions. Every
seventh injured was treated as an in-patient on average in five days. Non-crash victims consumed 57% of all in-patient days.
Conclusions: The aerodynamic cross-wind factor merits more studies. Injury reducing measures against alighting injuries, addressing especially step height and slippery conditions, may have a great potential to reduce these injuries. Rear-end collisions by other heavy vehicles in urban
areas, causing a high number of “whip-lash” injuries, also need to be further addressed. The newly introduced law on compulsory seat belt use inlong distance coaches may have a potential to reduce single vehicle crash and some collision injuries.
Key Words: Aerodynamics, Alighting, Bus and coach, Injury incidents, Cross-wind

1. INTRODUCTION
Unlike the decreasing trend for car occupant injuries, deaths and injuries involving occupants of buses andcoaches have been “stubbornly stable” over recent years
in the European Union1 and in Sweden an increasing
trend has been observed2. These incidents span from masscasualty crashes, often with massive media exposure, tonon-crash incidents with only one person involved, e.g.
a passenger falling when alighting a bus. Researchers andauthorities often report spectacular mass casualty
crashes3-8. However, non-crash events may be equallyinteresting from an injury mitigation point of view, especially for elderly occupants, as the European Coach and
Bus Occupant Safety project (ECBOS) and other haveindicated5, 9-12.
Since bus and coach incidents are relatively rarecompared to other traffic injury incidents, data need to
be gathered over a long time span. Moreover, as Nilsson13
pointed out, a well-defined geographical area needs to be
selected for epidemiological studies. To assess the impact
of different bus and coach occupant injuries from a pub-lic health perspective, hospital data, instead of police data,
are preferred2.
The aim of the present study was to provide an
overview of the injury epidemiology in both crash andnon-crash injury incidents among bus and coach occupants. The data set chosen is from a well-defined geographical area and is a “total survey material” from the
medical sector.

2. MATERIAL AND METHOD
2.1

GeneralThe material comprised 284 cases with injuries sustained during a bus or coach journey within the Umeåmedical district. All included patients were treated at the
emergency department (E.D.) at the University Hospitalin Umeå during the ten-year period 1994-2003. The hospital is located in northern Sweden and is the only hospital within a well-defined catchment area with a radiusof 50-60km around Umeå. The population has increased
from 125,000 inhabitants in 1994 to 137,000 in 2003.
Winter conditions prevail usually between November
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through March.
At the E.D. both in- and out-patients from the area
are treated. At small health care centres in the area, only
a few per cent of those with vehicle related minor injuries are treated. At the visit at the E.D. the injured person answers a questionnaire about the injury incident. In
some cases, these data were retrieved by later interview.
Data from medical records and from police investigations
are also included in the database. By checking against thehospitals compulsory E-number-registration for “externalcause” to in-patient treatment14,15 a loss of in-patients waseliminated. The misses of out-patients in the hospital’s
injury registration is 2-5%, mostly minor injuries16.
2.2 Definitionsa) Buses and coaches included were M2 and M3 vehicles, i.e. vehicles with more than eight seats for passengers17. Buses are aimed mostly for city traffic andcoaches for long distance traffic.
b) The injuries were classified according to the Abbreviated Injury Scale (AIS), where MAIS denotes theMaximum AIS 18. AIS=1 is a minor injury (e.g.
wound, finger fracture), AIS =2 is a moderate injury(e.g. fracture, concussion), AIS =3 is a serious injury(e.g. limited intra-cranial or abdominal bleeding) etc.
up to AIS=6, which is a maximal (deadly) injury.
c) Days in hospital for in-patients; the days for signingin and out together were counted as one (24 hours)
hospital day.
d) “Alighting and boarding”- incidents: non-crash incidents with a bus or coach at stand still.

e) “Non-crash” incidents in a moving bus or coach: injury incidents among occupants in a moving bus orcoach, e.g. the occupant was stumbling, lost balance,
fell etc.
In order to compute injury incidence, travel statistics were collected from local and regional bus companies, and from a survey made by local authorities19.
The structure of the material is presented in Figure 1.

3. RESULTS
3.1 All incidents
3.1.1 Injury incidence and reporting rate
The average number of injured occupants per year
was 28.4. The injury incidence was 2 per 10,000 inhabitants on average over the 10 year period. The incidence
of injured in non-crash incidents increased by 24% andin crash incidents by 30% between the first and second
half of the study period.
The police reporting rate to the official traffic injury statistics was 68 (38%) of the 178 who were injured
in a moving vehicle, and therefore should have been reported according to the official statistics rules. However,out of the 130 injured in only crash incidents, 68 (52%)
were reported, i.e. all reported by the police were fromcrashes.

Bus and coach injury incidents; 284 injured

Crash incidents n=130 (46%)

Collisions withother vehicles
n=86 (30%)

Single vehicle
crashesn=44 (16%)

Non-crash incidents n=154 (54%)

Alighting (102) andboarding (4)n=106 (37%)

Injured in moving
vehicle by e.g. fall
n=48 (17%)

Fig. 1 Number of injured in different types of incidents

80 • IATSS RESEARCH Vol.29 No.1, 2005

INJURY EVENTS AMONG BUS AND COACH OCCUPANTS

U. BJÖRNSTIG, P. ALBERTSSON, J. BJÖRNSTIG, P-O BYLUND, T. FALKMER, J. PETZÄLL

3.1.2 Age, gender and road typeThe mean age was 42 years (SD 20, median 43,
range 2-91). The distribution of injured by age and gender is presented in Figure 2. At least 201 (71%) were injured on urban streets/roads, while 59 (21%) were injured
on rural roads (Table 1).
3.1.3 Day and month
During the six months October through March, 212(75%) of all occupants were injured. The proportion ofjourneys during these months was 63%19. The age groups
up to 60 experienced 78% of their injury incidents during these months, and for those 60 and older the corresponding figure was 63%.
All major injury incidents, comprising five or moreinjured occupants, occurred during the five winter months
November through March. The month with the highest
injury rate was January (65/23%).
The injury frequency was on average twice as highon weekdays compared to weekend days. More than half
(171/60%) were injured during five hours of peak traf-

fic; 7-9, a.m. plus 2-5 p.m. However, half of them (83/29%) were injured during the hour between 8-9 a.m. Mostof them (67) were injured in three major injury incidents.
3.1.4 Injuries
As shown in Table 1, almost one-third, had MAIS
2+ injuries (moderate or more serious injuries); 36% of
the men and 29% of the women. Forty-one percent of
those 50 years of age or older had MAIS 2+ injuries, as
had 24% of the younger. The proportion of MAIS 3+ injuries was for men 6% and for women 5%, and for people
50 years or older 11% and for younger 2%, respectively.
The proportion of injured with MAIS 2+ injuries
was higher (40%) on rural roads than on urban streets androads (27%). At least 10 of 15 cases with MAIS 3+ happened on rural roads.
Table 2 presents the injury type and location for all
the 340 injuries in the 284 occupants. Most frequent(26%) was injuries to the lower extremities, a majorityof them sustained when alighting a bus or coach. Injuries to the neck were almost as frequent (24%), many ofthem sustained when another heavy vehicle hit from behind the subjects bus or coach. One-fifth (20%) sustained
fractures, most often to the upper extremities.
3.1.5 In-patient treatment
Forty-three (15%) occupants were treated as in-patients for a total of 221 days. From non-crash incidents
22 injured spent 126 days in hospital, i.e. on average 5.7
days and from single vehicle crashes 20 occupants spent
94 days in hospital i.e. on average 4.7 days. Those 14 injured when alighting or boarding spent on average thelongest in hospital time, 6.7 days. From collisions only
one person was in need of in-patient treatment for one
day. One elderly patient died nine days after the injury
incident from cardiac complications, otherwise no one
died as a consequence of their injuries.

Fig. 2 Number of injured by gender and age

Table 1 Number of injured by injury severity, gender and urban/rural road
Urban street/roadn=201 (71%)

Rural roadn=59 (21%)

Unknownroad/street
n=24 (8%)

Total

Injuryseverity

Men

Women

Sum

Men

Women

Sum

MAIS=133 (81%)114 (73%)147 (73%)

7 (47%)

28 (64%)35 (60%)15 (63%)197 (69%)

MAIS=2

11 (17%)39 (25%)50 (25%)6 (40%)

8 (18%)

14 (22%)8 (33%)

72 (25%)

MAIS=3

1 (2%)

3 (2%)

4 (2%)

1 (7%)

4 (9%)

5 (9%)

1 (4%)

10 (4%)

1 (7%)

4 (9%)

5 (9%)

15 (100%)

44 (100%)

59 (100%)

24 (100%)

284 (100%)

MAIS=4Total

45 (100%)

156 (100%)

201 (100%)5 (2%)IATSS RESEARCH Vol.29 No.1, 2005 •81

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3.2. Crash incidents
3.2.1 Age and type of crash
In crashes, 130 were injured; 86 in 26 collisions
with other vehicles and 44 in 6 single vehicle crashes(Table 3). Occupants injured in collisions with other vehicles had a mean age of 34 years, while those injured insingle vehicle crashes had a mean age of 40 years.
A vast majority (76/88%) of the 86 collision victims were injured in urban areas. Sixty-seven (78%) of
the 86 were injured in collisions with other heavy vehicles, such as trucks (41 injured in 3 crashes) or buses/
coaches (26 injured in 6 crashes). Sixteen people were
injured in 15 different collisions with cars and 2 were injured when their bus collided with a bicycle and a moose
respectively. In one case the collision partner was unknown. The bus or coach was rear-ended in 7 occasions,causing minor and moderate injuries (MAIS 1-2) to 64
occupants. In 9 cases, the injured were standing in thebus or coach at the crash.
Of the 44 injured in single vehicle crashes, 43(98%) were injured on rural roads. In two major single

crashes, 40 occupants were injured. All 10 with MAIS
3+ injuries from single crashes were injured in these two
crashes. The police report indicated that strong crosswinds, in combination with slippery road conditions,caused the coach to deviate off the road in these two
crashes. This was confirmed by a calculation using an algorithm derived from wind tunnel testing3.
3.2.2 Injuries
Of those 86 injured in collisions, only 5% had
MAIS 2+ injuries (Table 3). The injury panorama werecharacterized (72%) by neck sprain or “whip-lash” injuries (AIS 1), caused by rear end impacts from otherheavy vehicles (Figure 3).
In single vehicle crashes, the proportion of MAIS
2+ injuries was highest of all groups (21;48%).The 44
injured sustained on average 1.6 injuries per person (Figure 3). The most frequently injured body regions werehead and face, followed by upper extremities and chest.
One fourth of the injuries were fractures.

Table 2 Type and localization of all 340 injuries in the 284 injured
Laceration/contusion

SprainFracture/dislocation

Concussion/
intracranial bleeding

Other injury

Total

Head/face

32

—

3

15/2

—

52 (15%)

Neck

4

78

—

—

—

82 (24%)

Chest

14

1

8

—

2

25 (7%)

Abdomen/pelvis

10

2

7

—

1

20 (6%)

Upper extremity

36

7

30

—

—

73 (21%)

Lower extremity

34

29

21

—

4

88 (26%)130 (39%)

117 (34%)69 (20%)17 (5%)

7 (2%)

340 (100%)

Total

Table 3 Number of injured in crashes by injury severity and urban/rural road
Collision with other vehicle
n=86 (66%)
Urban street/roadn=76 (88%)

Single vehicle crash
n=44 (34%)

Rural roadn=9 (11%)

Unknownstreet/roadn=1 (1%)

Injuryseverity

FrontalimpactSide
impactRear
impactFrontalimpactSide
impactRear
impactSide
impact

MAIS=13 (100%)8 (88%)

63 (98%)2 (67%)

4 (80%)

1 (100%)1 (100%)*Urban
street/roadn=1 (2%)

Rural
road
n=43 (98%)

1 (100%)22 (51%)

MAIS=2—

1 (12%)

1 (2%)

1 (33%)

1 (20%)———

11 (25%)

MAIS=3

—

—

—

—

—

—

—

—

5 (12%)

MAIS=4

—

—

—

—

—

—

—

—

5 (12%)Total

3 (100%)9 (100%)64 (100%)

3 (100%)5 (100%)1 (100%)1(100%)

1 (100%)43 (100%)*

Collision with a moose

82 • IATSS RESEARCH Vol.29 No.1, 2005

INJURY EVENTS AMONG BUS AND COACH OCCUPANTS

U. BJÖRNSTIG, P. ALBERTSSON, J. BJÖRNSTIG, P-O BYLUND, T. FALKMER, J. PETZÄLLCollision with other vehicles,
92 injuries (86 occupants).

Head/face 21 (30%)

Head/face 3 (3%)
2 (67%)
1 (33%)

Concussion
10 (48%)
Laceration/cut
5 (24%)
Contusion
2 (10%)
Fracture
2 (10%)
Subdural hemorrage 2 (10%)

66 (99%)1 (1%)

Neck 6 (8%)

ContusionLaceration/cut

Neck 67 (73%)

SprainContusion

SprainContusion

Chest 4 (4%)
Contusion
SprainFracture

2 (50%)
1 (25%)
1 (25%)

Abdomen/pelvis 4 (4%)
Contusion
Sprain2 (50%)
2 (50%)

Upper extremities 9 (10%)
Contusion
FractureSingle vehicle crashes,
71 injuries (44 occupants).

6 (67%)
3 (33%)

5 (83%)
1 (17%)

Chest 13 (18%)
Contusion
Fracture
Other
Laceration/cut

7 (54%)
3 (23%)
2 (15%)
1 (8%)

Abdomen/pelvis 7 (10%)
FractureContusionLaceration/cut

4 (57%)
2 (29%)
1 (14%)

Upper extremities 19 (27%)
Lower extremities 5 (5%)
Contusion

5 (100%)

Contusion
Fracture
SprainLaceration/cut

8 (41%)
7 (37%)
2 (11%)
2 (11%)

Lower extremities 5 (7%)
Contusion
Fracture
Laceration/cut

3 (60%)
1 (20%)
1 (20%)

Fig. 3 Injury type and localization for those injured in crash incidents

3.3 Non-crash incidents
3.3.1 Age and type of incident
In non-crash incidents, 154 were injured; 118 (77%)
women and 36 (23%) men. The mean age was 49 years
for those injured when alighting or boarding and 42 forthose injured in a moving bus, e.g. by falling when thebus was braking.
Two-thirds (106) of the non-crash victims were
injured when alighting (102) from, or boarding (4), a
bus at stand still (Table 4). Contributing causes given
for alighting injuries were in 57 (56%) cases slipping on
wet or icy steps, or on the ground, and in 28 (27%) casesstumbling on the way out of the bus or coach.
One-third (48) of the non-crash victims were injured by falling, or by injuring themselves in some otherway, in a moving bus or coach. At least half (54%) were
injured because the bus or coach was braking or accelerating (Table 4). Of the remaining 46%, most people were

injured due to, e.g. stumbling or slipping when moving
in the bus during the tour, but in two cases (4%) people
were hit in the head by a falling TV-monitor and video
recorder, respectively. At least 31 (65%) of these 48 occupants were standing.
3.3.2 Injuries
Of the 106 injured when alighting or boarding atstand still, 46 (43%) suffered MAIS 2+ injuries, as did
16 (33%) out of the 48 who were injured in “non-crash”
incidents with moving vehicle (Table 4). Thirty-two percent in the age group younger than 50 years had MAIS
2+ injuries compared to 49% in the age group 50+.
The 154 occupants sustained 177 injuries (Figure 4).
A majority of the injuries (54%) sustained in the 106
alighting and boarding incidents were located to thelower extremities. Injuries sustained in “moving bus/
non-crash” incidents, were evenly distributed to the upIATSS RESEARCH Vol.29 No.1, 2005 •83

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Table 4 Number of injured in non-crash incidents by injury severity and type of mechanism
When the bus or coach was moving
n=48 (31%)

Bus or coach at a standstill n=106 (69%)

InjuryseverityHarshbraking

Acceleratingfrom a stand stillWhileridingOther andunknown mechanisms

AlightingBoarding

MAIS=113 (72%)5 (63%)

10 (67%)

MAIS=25 (28%)

3 (27%)

5 (33%)

MAIS=3———

1 (14%)Total

4 (57%)

58 (57%)2 (50%)

92 (59%)2 (29%)

40 (39%)2 (50%)

57 (38%)4 ( 4%)—

5 (3%)

MAIS=4

—

—

—

—

—

—

—

Total

18 (100%)

8 (100%)15 (100%)

7 (100%)102 (100%)

4 (100%)154 (100%)Bus or coach at stand still,
120 injuries (106 occupants).

Head/face 13 (23%)

Head/face 15 (13%)
Contusion
Concussion
Laceration/cut
Fracture

7 (46%)
4 (27%)
3 (20%)
1 (7%)

Laceration/cut
Contusion
Concussion

8 (61%)
4 (31%)
1 (8%)

Neck 6 (11%)

Neck 3 (3%)
SprainContusion

2 (67%)
1 (33%)

SprainContusion

5 (83%)
1 (17%)

Chest 6 (11%)

Chest 2 (2%)
Contusion
Fracture

1 (67%)
1 (33%)

Contusion
Fracture

3 (50%)
3 (50%)

Abdomen/pelvis 4 (7%)

Abdomen/pelvis 5 (4%)
Contusion
Fracture

When the bus or coach was moving,
57 injuries (48 occupants).

3 (60%)
2 (40%)

Contusion
Fracture
Other injury

2 (50%)
1 (25%)
1 (25%)

Upper extremities 29 (24%)
Upper extremities 16 (27%)

FractureContusionLaceration/cut
Sprain11 (38%)11 (38%)4 (14%)
3 (10%)

FractureContusion
Sprain9 (56%)
5 (31%)
2 (13%)

Lower extremities 66 (54%)

Lower extremities 12 (21%)

SprainContusion
Fracture
Laceration/cut
Dislocation
Tendon injury

Contusion
Fracture
SprainDislocation
Laceration/cut

28 (42%)13 (20%)13 (20%)4 (6%)
4 (6%)
4 (6%)

7 (59%)
2 (17%)
1 (8%)
1 (8%)
1 (8%)

Fig. 4 Injury type and localization for those injured in non-crash events

per extremities, head and to the lower extremities.

4. DISCUSSION
The injury incidence was two per 10,000 inhabitants and year. The genuine quality of this total survey data84 • IATSS RESEARCH Vol.29 No.1, 2005

from the medical sector provides a fair and robust indication of the injury incidence in a well-defined geographic area, as well as of the medical burden different
types of incidents and injuries put on the health sector.
To the increased trend of non-crash injuries from the firstto the second part of the study period, improved accessibility for more vulnerable elderly and disabled may havecontributed, as well as an increased number of journeys

INJURY EVENTS AMONG BUS AND COACH OCCUPANTS

U. BJÖRNSTIG, P. ALBERTSSON, J. BJÖRNSTIG, P-O BYLUND, T. FALKMER, J. PETZÄLL

reported by bus companies in the area. The increase ofpeople injured in crashes indicate a more uncertain trend,
as a few mass casualty crashes may have a strong influence on data.
Only 38% of the bus occupants injured in a moving bus or coach were included in the official police-reported traffic injury statistics, as they should have been.
This put emphasis on the importance to use data from the
medical sector, instead of the official statistics, to get a
representative view of the bus and coach occupant injury
risks, and of the impact on the health sector.
From the medical point of view, the importance of
non-crash incidents was obvious. More than half were
injured in such incidents, 43% had MAIS 2+ injuries and
57% of all days at hospital were caused by non-crash
events. However, also single vehicle crashes had a highproportion of non-minor injuries (48%), while the corresponding proportion for those injured in collisions only
was 5%. From the health sector’s view, collisions werethus no major emergency problem in this data set. Even
if not represented in this data set, severe collisions between coaches and trucks are a reality2,20 as, e.g. the recently reported collision in the neighbouring country
Finland, causing the death of 23 young people21.
Indications that aerodynamic factors related to highsided (about four metres) coaches, strong cross-winds,and slippery road conditions, contributed to two major
single vehicle crashes (Figure 5) were found. This hazard is not, or only scarcely, addressed in the literature andmerits more interest. The Swedish Aeronautical ResearchInstitute22 has after wind tunnel studies, developed an
aerodynamic algorithm usable to calculate the wind influence on coaches. Albertsson et al.,3 have in a separate

Fig. 5 A major single coach crash with 34 injured
caused by severe cross-wind and slippery roadconditions3 (Photo: L. Danielsson)

investigation of one of these crashes given an example
on how the algorithm may be used and Petzäll et. al.23,
in a forthcoming paper, will report ten such crashes. Consequently, some coach operators in Sweden have, to increase the safety, recently expressed an intention to
introduce speed restrictions on high-sided coaches inwindy weather.
The frequently reported “whip-lash” injuries fromcollisions may in some cases cause important long-term
consequences and high sickness benefit costs24-26. These
injuries might be reduced by higher seat backs/head restraints also in local buses, and by effective snow-clearance and other means of slip control.
Three-quaters of the injured were women and themean age were highest (49 years) among those injured
when alighting from, or boarding, a bus. This may reflect
higher travelling frequency, greater vulnerability, and the
5-6 years longer average life span for women compared
to men27-29. The lowest mean age (34 years) had thoseinjured in collisions. High proportion of young people
travelling during rush hours19, may have contributed to
the low mean age in these incidents30.
Two-thirds of those injured in non-crash incidents
were injured when alighting from a bus or coach and 43%
had MAIS 2+ injuries. Similar11, as well as higher9,31, andlower shares32, of alighting injuries have been reported.
Alighting thus seems to be the major problem, having
similarities with the well-known problem of falling instairs, which most often happens on the last step whengoing downstairs33,34. For many years, the authorities
have regulated the design of buses to make them moreaccessible for elderly and for people with disabilities35,36.
From 1998, economic state subsidies equivalent to
100,000 USD per vehicle has been available to facilitate
this process37. The subsidy requirement was, e.g. that thebuses would have “low floor” entrances or a “kneeling”
mechanism, reducing step height to 250mm in the firststep from the ground and to 200mm in the other steps.
To compare, the standard height for steps in buildings is
180 mm, while in elderly homes the recommended heightis 120-160mm. This means that even in subsided buses
and coaches aimed for elderly and disabled, the stepheight may be twice as high as in buildings.
Especially high sided, double decked, wind sensitive coaches with “low floor” entrance got this support(Figure 6). Realizing that the lifespan of such a coachwould be 10-15 years, these specific problems20,38 willremain for many years. Thus, this “good intention” subsidy seems to have created several problems and adverse
effects. Further, to move between the upper and lower
IATSS RESEARCH Vol.29 No.1, 2005 •85

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Fig. 6 A typical double-decked, subsided, windsensitive, coach with rear baggage and goods
compartment further impairing stability. This
type of coach is used for combined transport ofpassengers and goods in rural areas in Sweden.
(Photo: P. Albertsson)

Fig. 7 An example from Curitiba in Brazil of a public
transport system, minimizing level problems inboarding and alighting, facilitating and speeding
up exchange of passengers and giving shelter
to waiting passengers who pay before entering
the tube. The system was built in cooperation
with the bus manufacturer Volvo.

levels in such a coach also requires full locomotor skills.
Strategies to increase safety of these vehicles thus need
to be developed39.
One good injury reducing measure would be toeliminate the level difference between the bus stop andthe floor in the bus, as e.g. in the subway. A Volvo built
system in Curitiba, Brazil (Figure 7), may illustrate one
way to solve this problem. An additional risk factor whenalighting is the risk of slipping on badly snow cleared bus
stops40-42. Effective snow clearance and slip control measures at bus stops, heating coils in the entrance steps ofthe bus, and ground heating, may have a potential to reduce many of these wintertime injuries.
The finding that standing passengers, especially
under sudden acceleration or deceleration, fell and were
injured, raises the question of improvement of driving
technique and interior design. Standing passengers may
be difficult to avoid in urban traffic, why easily accessible handrails and a soft driving manner may be advocated to compensate some of these risks. Stress among
drivers due to tight timetables may also compromisesafety32. Especially during wintertime (when 3/4 was injured), this may happen. Some bus operators actually havethe same timetables as during summer, despite frequent
bad road conditions. The bus operator may also have to
pay fines to the principal if they do not keep the timetable. All these factors may compromise safety, especiallywhen slippery conditions prevail, as was the case in thetwo biggest mass casualty crashes in this data set.

At least a 1/4 were injured in such types of incidents (single crashes and collisions other than rear end
impacts) that a seat belt might have reduced their injuries8,43,44. A study on roll-over crashes (as our major
single vehicle crashes) indicated that a two point seat belt
would reduce half of the MAIS 2+ injuries, and that afurther reduction might be possible to achieve by a threepoint belt45.
In conclusion, the aerodynamic crosswind factor isa new pre-crash factor, which merits more studies. Noncrash incidents, especially alighting from a bus, needs tobe addressed with a focus on step height and slippery conditions. Rear-end collisions by other heavy vehicles inurban areas, also need to be addressed by e.g. better seats.
The results from the present study may form a base fordiscussing different injury mitigation strategies and improvement of bus and coach safety.

86 • IATSS RESEARCH Vol.29 No.1, 2005

REFERENCES
1. European Commission. The Route to Road Safety. European Commission. (2002).
2. Enhanced Coach and Bus Occupant Safety. Task 1.1 Statistical
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ACKNOWLEDGEMENTS
The Swedish National Road Administration, (SNRA) financed this study. The Swedish National Board of Welfare has also
supported our studies of major bus and coach incidents. The authors also wish to thank Gustav Hedström Department of Surgicaland Perioperative Sciences, Division of Surgery, Umeå University,Umeå, Sweden, for contributions in the data collection.

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