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Occupational road trauma and permanent medical impairment
Safety Science Vol. 26, No. 3. PP. 187-200. 1997 0 1997 Elsevier Science Ltd. All rights reserved Printed in the Netherlands 0925.7535/97 $I 7 00 + 0.00
Pergamon
PII: SO9257535(97)00042-S
OCCUPATIONAL ROAD TRAUMA AND PERMANENT MEDICAL IMPAIRMENT Per-O/of Bylund a,*, U/f Bjarnstig a, Tore J. Larsson b,c a Ume2 Accident Analysis Group, Department of Surgery, Umea University, S-901 85 UmeB, Sweden b Institute for Human Safety and Accident Research (IPSO), Stockholm, ’ University of Ballarat, Ballarat, Victoria, Australia
Sweden
Abstract-Medically impairing occupational injuries sustained in traffic in Sweden were analysed. More than half of the cases with a permanent medical impairment were caused by minor injuries. Soft tissue injuries to the neck (whiplash injuries) made up nearly half of all permanently impairing injuries, and half of these were caused by rear-end collisions. As a final result, just over one third (37%) of the total group had a permanent decreased work capacity, or needed to change jobs because of residual problems from their injuries. Professional drivers had the highest injury incidence per employed and they accounted for 28% of the total number of permanent impairment cases, and for 43% of the fatalities. Professional drivers also had a higher percentage of serious injuries and severe permanent impairments than other occupational groups. This might be associated with the low use of safety belts (16%) compared to other occupational groups, where usage was 4-5 times higher. This occupational injury problem ought to be handled in the same way as other occupational safety problems, i.e. protective equipment in a vehicle should be used and the use of safe vehicles should be encouraged. 0 1997 Elsevier Science Ltd
1. Introduction The total number of accidental deaths during work-time has decreased greatly in Sweden since the middle of the 195Os, from over 400 per year to approximately 100 (Official Statistics of Sweden, 1992). Vehicle-related injuries are today the largest individual cause of death in Swedish working life (Official Statistics of Sweden, 1992). Many professional groups besides professional drivers use motor vehicles in their work. Injuries sustained in traffic have not been looked upon as a work injury problem but rather as ‘traffic accidents’. Injuries giving rise to medical impairment probably have special characteristics. In a thorough review of the literature, we have not found any reports dealing with medically impairing injuries sustained in vehicle crashes in traffic during work-time.
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188
The aim of this study is to analyse the epidemiology and consequences impairing injuries sustained in traffic during work-time for different occupation
P.-O.
Bylund
et al.
of medically groups.
2. Material and methods
Injuries sustained during work-time, in/on a registered motor vehicle, that resulted in permanent impairment (n = 466) or death (n = 40) were analyzed. The injury events occurred between 1 January 1988 and 31 December 1990 in Sweden. Data on these injuries were extracted from the Swedish Work-Related No-Fault Liability Insurance (TFA) database on 1 August 1993. This insurance, which is handled by a consortium of the largest insurance companies in Sweden, covers virtually all employed on the Swedish labour market, and pertains to almost all work-related injuries and diseases with more than seven days of sick leave. Bank tellers and finance clerks were not covered by this insurance system. The study does not consider injuries that occurred outside the general traffic area or on the way to or from work. A Swedish study (Bjornstig and Larsson, 1994) showed that about 90% of those injured at work, and suffering a permanent medical impairment, reported this to the insurance and compensation program. Injuries were classified according to the Abbreviated Injury Scale (Committee on Injury Scaling, 1990) where MAIS is Maximum AIS. Soft tissue injuries to the neck also named sprain, strain, distorsio colli (whiplash injuries) are referred to using the medical term distorsio colli. The amount of sick leave was calculated as the number of l/l days off work within two years after the crash. In Sweden, permanent medical impairment is defined in a Classification Manual used by the Insurance Industry (Personskadekommitten inom Fijrs’akringsbranschens Serviceaktiebolag, 1989). Medical impairment is a measure of the loss of body function as a result of injury and is expressed as a percentage. When the injury has reached a stable condition and there is no expectation of improvement, the exact medical impairment is determined on basis of an examination by a medical specialist. AIS, indicates the AIS-value of the impairing injury. In the case of multiple impairing injuries, AISi refers to the highest AIS,-value among the injuries in question. Injuries resulting in permanent impairment which had not received a final assessment from the insurance company by 30 June 1994 (3.5-6.5 years after the injury) (32; 7%) were, after a review of the appropriate journals and interviews, awarded an impairment level equal to the average for that type of injury. In one case it was too early to assess final level of impairment, which could not be more closely determined than 2 10%. The Nordic Classification of Occupations (Nordisk Yrkesklassificering, 1984) was used to allocate the cases according to occupation. The group professional drivers includes drivers of trucks, buses, taxis and delivery cars (NYK 640641). The total number of people working in each group was obtained from the Official Statistics of Sweden (Folk och bostadsrakningen 1990, 1992). The size of the vehicles was classified as: small/medium-sized cars (kerb weight ( 1250 kg), large cars (> 1250 kg), light cargo vehicles (< 3.5 tons; includes minibuses, vans, pick-up trucks and jeeps) and heavy trucks/buses (kerb weight 2 3.5 ton).
Occupational road trauma and permanent medical impairment
3. Results
3.1. Age, sex and position in the vehicle
Of the 506 injured, 40 sustained fatal injuries and 466 received impairing injuries; 442 (87%) had been driving the vehicle. A majority (365; 72%) were men. Nearly one fifth (n = 7) of those who died were women. The average age of the injured men was 41 years and of the women 39 years.
3.2. Incidence of injuries among different occupational
groups
Professional drivers, especially those driving delivery cars/light cargo vehicles and taxis had the highest injury incidence per employed among the different occupational groups (Table I>.
Table 1 Annual number of fatally occupational groups
injured,
medically
impaired
and injury
incidence
per 100000
employed
in different
Occupation
Fatally injured
Impaired
Incidence
Professional, technical and related work (NYK 001-009) Educational work (NYK 030-035 +037-039) Health and nursing work (NYK 100-109 + 154) Children nurses, pre-primary education teachers (NYK 153 + 036) Administrative, managerial and clerical work (NYK 200-299) Business service salesmen, shop assistants etc. (NYK 313-333) Agriculture, horticulture and forestry management (NYK 400-411) Busdrivers (NYK 640.10) Taxidrivers and passenger car drivers NYK (640.20-30) Truck drivers (NYK 641.10) Delivery car/light goods vehicle drivers (NYK 641.20) Mail sorting clerks and postmen (NYK 681) Messengers (NYK 682) Metal machine work and building metal work (NYK 75 l-759) Electrical and electronics work (NYK 761-765) Construction workers (NYK 791-799) Stationary engine operation work material handling (NYK 861-873) Firemen (NYK 901) Policemen (NYK 903) Watchmen (NYK 906) Caretaking and cleaning work (NYK 931-939) Conscripts (NYK x19) Other Unknown
5
6 3 2 2 2 3 4 40 114” 39 142 18 12 2 5 2 3 22 22 18 4 6
3 2
45 14 31 12 29 29 8 20 45 53 12 15 8 19 14 7 6 5b 11 6 18 8 50 1
Total
40
466
a One test driver is excluded in the estimation b Three firemen working as paramedics.
2 5 1
1 4 4 8 1 1
2
1
of injury incidens for taxi drivers.
_ 4
190
P.-O. Bvlund et al.
Table 2 Number of fatalities and permanently
medical impaired in different type of crashes
Crash mechanism
Fatally injured
Impaired
Total
Multi-vehicle
26 (65%)
330 (71%)
356 (71%)
18 7 _ _
107 120 78 20 5
125 121 85 20 5
8 (20%)
124 (27%)
132 (26%)
crashes (70%)
Frontal vehicle-to-vehicle crashes Rear impact by another vehicle Vehicle-to-vehicle side crash at intersection Crashed into the rear of another vehicle Other type of multi-vehicle crashes Single-vehicle
1
crashes (26%)
Crashes into stationary object Drove off the road and overturned Skidded and landed in a ditch Other type of single-vehicle crashes
4 2 2 _
Vehicle-train collisions (2%) Crashes involving game (1%)
5 (13%) 1(3%)
60%) 6 (1%)
11(2%) 7 (1%)
40 (100%)
466 (100%)
506 (100%)
Total
44 36 25 19
48 38 27 19
3.3. Type of crash Table 2 shows that front- and rear-end collisions were the most frequent. Single crashes accounted for more than one quarter of all injuries. For those travelling in heavy trucks, more than one fourth (19:66; 29%) were injured in collisions with other trucks or buses. One fifth (14:66; 21 %j of the heavy-truck occupants were injured in single-vehicle crashes when the truck turned over. In one case, a tank-truck driver drove into a ditch due to brake failure. More than a third (9:26; 35%) of those injured in a bus were injured when the bus collided with a truck or with another bus. At least six (7%) of the truck and bus occupants were ejected from the vehicle in the crash. In three crashes, taxi drivers were injured while operating the taximeter/computer when driving. 3.4. Crashes incoluing emergency
vehicles
A total of 23 people travelling in emergency vehicles were injured. Twelve policemen (six in cars, five on motorcycles and one in a minibus) were injured, two of them during ‘emergency driving’. Nine persons were injured in ambulances, five were ambulance personnel, three were nurses and one was a patient. Six of these were injured during ‘emergency driving’. Two firemen were injured, both during ‘emergency driving’. 3.5. Injury sever@ More than half (55%) of the 466 permanently impaired had only minor injuries (MAIS = I ), while 76 (16%) sustained serious (MAIS 2 3) injuries. Forty people died (MAIS = 5-6). Amongst the permanently impaired professional drivers of four-wheeled motor vehicles, 29 (22%) had MAIS 2 3 injuries, whilst in the other professions the number of (MAIS 2 3) injuries was lower (43; 13%).
Total
Fatal injuries
Multiple impairing injuries
Distorsio colli Fracture/luxation Lower extremity Upper extremity Fractured spine Sprain upper extremity Sprain and strain of the back Sprain lower extremity Brain, eye and other facial injury Other injury
Single impairing injury
injury
Impairing
140 (28%)
7
16
I
183 (36%)
14 7104%)
6
4
3 _
4 _
5 4
27
11 7 7 4 2 _
17 9 11 6 2 2
12 5 3 6
1
21
n = 61
91
n = 142
n= 117
Light cargo vehicle
80
Kerb weight > 1250 kg
car
Kerb weight I 1250 kg
Passenger
injury, fatalities and type of vehicle
Table 3 Impairing
92 (18%)
12
11
2 2
15 10 I 4 7
21
n = 69
Heavy truck/bus
13 (3%)
1
2
1
_ _ _
4 3 2 _
n = 10
Motorcycle
7 (1%)
_
1
_
I
2
_
I
_
2
n=6
Other/unknown
506 (100%)
40 (8%)
61(12%)
59 (12%) 35 (7%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) I3 (3%) 4 (1%)
221(44%)
n = 405
Total
P.-O. Bylund
192
3.6. Type of vehicle and permanent
et al.
medical impairment
The largest group of people had been travelling in large cars, but nearly a fifth had been travelling in heavy trucks or buses (Table 3). The ratio of fatalities to permanent impairment cases was twice as high for those travelling in heavy trucks or buses (12:80; 15%) as for those travelling in other four-wheeled vehicles (27:367; 7%). A majority (171; 66%) of the 259 car occupants with a single impairing injury sustained distorsio colli injuries. The proportion of extremity fractures was nearly the same among those injured in large cars (26; 18%) as among those injured in small- or medium-sized cars (17; 15%), but the number of people receiving fractures of the spine was nearly four times higher in large cars (n = 11) than in small- or medium-sized cars (n = 3). In heavy trucks and buses nearly half (32; 46%) of the 69 with a single impairing injury, sustained fractures of the extremities (n = 25) or spine (n = 7), while less than a third (21; 30%) sustained permanent impairment due to distorsio colli. 3.7. Permanent medical impairment, injury type and severity The impairment was caused by minor injuries (AIS, = 1) in more than half of the cases (27 1; 58%) (Table 4). Among these, 2 19 (8 1%) people sustained a distorsio colli injury and just over half (n = 114) of these were caused by rear-end impacts. Two thirds (81; 66%) of the 122 women and less than half (140; 48%) of the 291 men with impairing injuries had a distorsio colli diagnosis. Just over a quarter of the impairments were caused by a moderate injury (AIS, = 2). In this group, fractures and luxations of the lower and upper extremities were most common. Sixty-one people sustained multiple impairing injuries, often head injuries (n = 34) in combination with fractures (n = 2 1) and/or distorsio colli (n = 20). There was no difference noted in the age groups between minor and serious injuries.
Table 4 Distribution of AIS, among 465 cases.with AIS, classification) Impairing
injury
medical impairment.
(One person with a cold injury is excluded
AIS,
Total
1
2
3-5
Single impairing injury
261
108
35
Distorsio colli Fracture/luxation Lower extremity Upper extremity Fractured spine Sprain upper extremity Sprain and strain of the back Sprain lower extremity Brain, eye and other facial injury Other injury
219
2
Multiple impairing injuries
37 26 25 3
10 271 (58%)
221 (47%) 22 4 5
4 8
4
24
27
132 (28%)
404 037%)
62 (13%)
59 (13%) 35 (8%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) 13 (3%) 3 (1%) 61 (13%) 465 (100%)
in the
Occupational road trauma and permanent medical impairment Table 5 Impairing
injury and days of sick leave
Impairing
injury
Single impairing
193
Days of sick leave
injury
0
I-30
31-90
91-180
181-365
>365
Unknown
n= 35
n = 68
n= 87
n = 66
n=48
n = 98
It=3
fl=405
50
44
30
20
4-l
3
221 (47%)
3
9 14
12 10
14 2
24 3
_ _
6 4
3 2
4 2
7 3
10 5
_
1 3 1
6 3 6 _
1 3 2 2
1 1 _
4 _
-
3 2
_ _
59 (13%) 35 (8%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) 13 (3%) 4 (1%:)
8
6
7
8
32
-
61(13%)
Distorsio colli 27 Fracture/luxation Lower extremity 3 Upper extremity Fractured spine 4 Sprain upper extremity 1 Sprain and strain of the back _ Sprain lower extremity _ Brain, eye and other facial injury _ Other injury Multiple impairing
injuries
Total
Total
-
35(8%) 7606%)
9300%)
73(16%)
56(12%)
130(28%) 3(1%)
466 (100%)
3.8. Duration of sick leave Over half (32; 53%) of those with multiple impairing injuries and nearly one quarter (98; 24%) of those with a single impairing injury were on sick leave for longer than one year (Table 5). Of the latter, 47 (48%) had the diagnosis distorsio colli, 24 (24%) had a fracture/luxation of a lower extremity and 10 (10%) had a fracture of the spine. Twenty seven of those who had a distorsio colli injury had not been on sick leave the first two years after the injury. Distribution over age was the same for those with short- and long-term ( > 1 year) sick leave. 3.9. Degree of medical impairment from different injuries Twenty-two (36%) of the 61 with multiple impairing injuries had a severe medical impairment (2 20%), this was 4.5 times more often than those with a single diagnosis (31; 8%) (Table 6). Four of the 221 with the diagnosis distorsio colli had an impairment degree of 20% or more, which is higher than the normal 5-15% for this injury. There was no difference in the age distribution between those with severe (2 20%) and less severe levels of medical impairment. In four-wheeled vehicles, severe medical impairment ( 2 20%) was almost twice as common amongst professional drivers (21; 16%) as amongst those in other occupations, 3.10. Social consequences Over one third (170; 37%) of the 466 who sustained a medical impairment could not return full-time to their previous work (Table 7). Sixty-five (14%) had received a full-time early retirement on medical grounds, or were on full-time sick leave when the analysis was made, 3.5-6.5 years after the injury. The proportion who had retired or retrained was just as high for
194
P.-O. Bylund et al.
Table 6 Impairing
injury and degree of permanent
Impairing
injury
medical impairment
Degree of impairment
Total
l-4%
5-9%
IO-19%
20- 100%
Unknown
Single impairing injury
n = 56
?I = 201
II = 111
n = 31
n=O
Distorsio colli Fracture/luxation Lower extremity Upper extremity Fractured spine Sprain upper extremity Sprain and strain of the back Sprain lower extremity Brain, eye and other facial injury Other injury
23
126
68
4
221 (47%)
4 13 2 6 2 2 2 2
23 17 14 8 9 5 5 _
20 3 7 5
12 2 7
59 (13%) 35 (8%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) 13 (3%) 4 (1%)
3
23
Multiple impairing injuries Total
59 (13%)
230 (49%)
n = 405
2 2
I I _
2 2
4 _
12
22
1
61 (13%)
53 (12%)
1
466 (100%)
123 (26%)
those who had sustained fractures, as for those who had been diagnosed with a distorsio colli injury. Amongst those with multiple impairing injuries, 29 (48%) retrained or retired either full or part-time. Amongst the 405 with only a single impairing injury, 141 (35%) were retired or retrained. Of those in early retirement or on full-time sick leave, most (44; 68%) were in the 40-59 year age group and 17 (26%) were under 40 years of age.
Table 7 Impairing
injury and social consequences
Impairing injury
Full-time early retirement
Part-time early retirement
Retrained for another work
Back to previous work
Unknown
Total
Single impairing injury
n = 55
n = 35
?I = 51
n = 262
n=2
n = 405
Distorsio colli Fracture/luxation Lower extremity Upper extremity Fractured spine Sprain upper extremity Sprain and strain of the back Sprain lower extremity Brain, eye and other facial injury Other injury
27 13 _
23 5 _ 3 2 1 _ _
28 8 3 5 2 2 2
2 _ _
I
I
141 33 32 17 13 8 7 9 2
-
221 (47%) 59 (13%) 35 (8%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) 13 (3%) 4(1%)
Multiple impairing injuries
10
I
12
31
1
61 (13%)
Total
65 (14%)
5 3 3 _ 4 _
42 (9%)
63 (14%)
293 (63%)
_ _ _
3 (1%)
466 (100%)
Occupational road trauma and permanent medical impairment n=133
195 n=65
n=169
100%1
n=60
I
25%
“_
SMALL/MEDIUM PASSENGER
LARGE PASSENGER
CAR
-
MAIW
CAR
m
LIGHT CARGO VEHICLE
MAIS=
n
BUS/HEAVY
TRUC IK
MAW3
Fig. 1. Injury severity and type of vehicle.
3.11. Severity of injury, impairment
and use
qf safety belts
The proportion of people with moderate or serious injuries (MAIS 2 2) was lowest amongst those travelling in small- and medium-sized cars, while the proportion was highest (50; 63%) in heavy trucks and buses (Fig. 1). Only 8 (6%) of those travelling in small- or medium-sized cars were severely (2 20%) impaired, while the proportion was highest (26; 15%) amongst those travelling in large cars (Fig. 21. Severe impairing injuries were twice as common (9:36; 25%) among taxi drivers as among other occupational groups (16:131; 12%) travelling in large cars. n-133 100%
n=65
n=169
n=60
r
75%
25%
0% SMALL/MEDIUM PASSENGER CAR
LARGE PASSENGER
Fig. 2. Medical impairment
CAR
LIGHT CARGO VEHICLE
BUS/HEAVY
degree and type of vehicle.
TRUCK
P.-O. Bylund et ~1.
196 n=133
n-65
n=169
n=80
100%
0% PASSENGER m
CAR Belted
PASSENGER
CAR
Unknown
VEHICLE
0
Non-belted
Fig. 3. Use of safety belt and type of vehicle.
The data relating to the use of safety belts is based upon information given by the people who survived the accident, as the police revealed safety belt usage in less than a third of the fatality cases. The use of safety belts was high (106; 80%) amongst the 133 who were injured in small- and medium-sized cars. Amongst the 80 travelling in heavy trucks or buses, only three drivers and one passenger were using safety belts (Fig. 3). Five of 23 occupants in buses were passengers. About a third (11; 31%) of the 36 taxi drivers travelling in large cars stated that they were using their safety belts at the time of injury. In one crash in which the taxi driver died, the paramedics found the safety belt fastened behind the driver’s back, apparently to turn off the safety belt warning light. The occupational groups dominated by civil servants and academics (158; 87%) complied best with the compulsory use of safety belts; those belonging to blue collar occupations had a lower compliance (81; 61%). Drivers of heavy trucks, buses and taxis were not included in this specific calculation, as they are exempt from the safety belt law.
3.12. Alcohol
Of the 40 occupants who died, 37 were drivers and 36 were tested for alcohol inebriation. Three (8%) tested positive with a blood alcohol concentration (BAC) of 0.3, 0.4 and 1.6 g/l, respectively. In another fatal crash, a motorcycle policeman died when he collided with a car which overturned. The car driver was inebriated. One surviving tank-truck driver suffered from delirium tremens during his hospital stay, caused by abstinence from alcohol. No alcohol blood test was performed in this case. Among all 466 injured, nine (2%) were injured when the other driver involved in the crash had, according to the police report, been under the influence of alcohol, or was suspected of driving while under the influence of alcohol.
Occupational
road waumu and permanent
medicnl
impuirmenr
197
4. Discussion
In proportion to the number of employed in each occupation, drivers of delivery cars/light cargo vehicles, taxis, buses and heavy trucks had the highest injury incidences. No exposure data was available for different groups of professional drivers, which makes a comparison on the risk per kilometre driven impossible to calculate. Bus and truck drivers also had the highest proportion of serious injuries and fatalities. This is noteworthy considering that they travel in vehicles that should be superior in most crash scenarios due to their weight (Evans and Frick, 1993; Evans, 1994). The predominant cabin design in Sweden (‘cab over’). however, places the driver near the front, and this could be a contributing factor to the unexpected result. This type of design is common in Sweden due to the current rules stipulating an overall maximum permissible length. These trucks are manufactured to maximize their carrying capacity, giving a minimal deformation zone. A change of regulations would might make it easier to build safe trucks. Light cargo vehicles have restricted deformation zones. and a somewhat old-fashioned design contributes to a lack of safety in these vehicles. An increased use of safety belts, introduction of air-bags and better deformation zones would make these vehicles safer. The tank-truck carrying petrol, which went off the road due to brake failure, could have caused a catastrophe. Failures in the brake systems of trucks are not uncommon (Jones and Stein, 1989; Strandberg, 1989a.b). Compulsory inspections, more than once a year, might be needed for heavy vehicles. Special problems are associated with the driving of emergency vehicles. A Swedish study has shown that the risk of injury was twice as high in ‘emergency driving’ as in ordinary driving (Transportforskningsdelegationen, 19791. Drivers of emergency vehicles often claim that other drivers fail to observe the emergency vehicle. dispite the use of blue emergency lights and sirens. Nearly half of the impairing injuries were distorsio colli injuries, but only half of them were caused by rear-end impacts. Other studies (Ono and Kanno, 1993; Lubin and Sehmer, 1993) show that, half and two-thirds, respectively, of all car crashes lead to neck injuries and that these injuries are increasing in frequency (One and Kanno, 1993). Improved head restraint design, clear information about the importance of correct adjustment of head restraints and high brake light placement (Evans, 1991) may reduce the incidence of this type of injury. Rigid rear tow bars mounted onto the frame of the car may also transfer unnecessarily strong impulses to the occupant seats in rear-end impacts, since they bypass the vehicle’s rear deformation zone. Measures to reduce the distorsio colli type of injury should be given a high priority. as long-term sick leave, early retirement and retraining are important consequences. How safety belt pretensioners and air-bags affect the frequency of these injuries sustained in frontal and side collisions remains to be determined. Interestingly, 27 people with distorsio colli were not on sick leave the first two years following the injury. This suggests that the symptoms became increasingly troublesome. However, the assessment routines within the Swedish Work Injury Insurance might also be relevant here and the high incidence of neck problems in the general population can make the association between cause and effect quite difficult to ascertain (Bovim et al., 1994). The social consequences were considerable. One third of those injured did not return to their previous work (half had been retired early on medical grounds and the other half received retraining). The economic consequences of these injuries are considerable as well. Neck injuries represent large pay-outs from the insurance
198
P.-O. Bvlund et al.
companies (Insurance Group Reports, 1995). In Sweden, this type of injury is reckoned to cost SEK 2 billion annually (USD 300 million) (Svensson, 1993). The use of safety belts by truck and bus occupants was low. It has been calculated that 27-60% of those injured in truck and bus crashes would have had less serious injuries if they had used a safety belt (Jar1 et al., 1989; Campbell and Sullivan, 1991; Svensson and VidCn, 1994). The risk of ejection, which can cause serious injuries, is eliminated with the use of safety belts. In the present study, at least 7% of those travelling in a bus or a truck were ejected from the vehicle. Other authors have cited higher figures (12-36%) (Jar1 et al., 1989; Campbell and Sullivan, 1991; Svensson and VidCn, 1994). An air-bag used in conjunction with a safety belt reduces injuries in heavy trucks (Svensson and Viden, 1994). Several studies have argued that in certain crash situations (accounting for perhaps 5-9% of all crashes), the use of safety belts would have worsened the injuries (Jar1 et al., 1989; Svensson and VidCn, 1994). In the present study, barely one third of the taxi drivers had been using the safety belts. The injury reducing potential is about 50% for both serious and fatal injuries (Evans, 1986; Campbell, 1987). A Finnish report suggests that safety belt use should be compulsory only when the taxi driver is alone in the vehicle (Finnish Motor Insurers’ Centre, 1993) since taxidrivers are said to fear being attacked by passengers in the car. The use of safety belts during travel in a vehicle during work-time should be considered as a question of occupational safety. As construction workers always wear helmets, drivers of cars, trucks and buses should wear their safety belts to protect themselves. In Sweden the employers have the responsibility for their employees safety and rehabilitation. A written contract between the employer and the driver, stipulating that the safety belt should be used when travelling in the company vehicles, would be one suggestion that might increase the safety belt use. However, a compulsory law for the driver groups today exempted from the belt law would be more efficient (Robertson, 1992). In the present study, 8% of the fatally injured drivers were driving under the influence of alcohol and in one surviving case, a tank-truck driver showed alcohol withdrawal symptoms during his hospital stay. Alleene et al. (1991) reported 13% drivers under the influence of alcohol in fatal occupational motor-vehicle crashes in the US. In Swedish traffic, the prevalence of alcohol inebriated drivers is about one per thousand (Valverius et al., 1982). Effective measures must be developed against alcohol and other drug use by drivers of trucks, especially those with dangerous loads. Today. the police in Sweden have no right to carry out routine tests for the use of illegal drugs other than alcohol, if there are no visible signs of inebriation. However, employers should consider regular and random alcohol and drug testing for drivers of dangerous goods vehicles. An independent company, agreed to by both employer and unions, could carry this out. Another method to consider would be to install ‘alto-lot’ on all heavy vehicles, especially those carrying dangerous loads.
5. Conclusions
Vehicle-associated injuries during work-time should be seen as an occupational safety problem. Optimal use of existing protective equipment should be encouraged, and the employer should provide vehicles with high safety standards. Measures for the prevention of distorsio colli injuries are of great importance.
Occupational
road trauma und permunent medical impairment
19’1
Acknowledgements The authors would like to thank Karin Torsteinsrud and Cecilia Oldertz at the Institute fog Human Safety and Accident Research (IPSO) in Stockholm for their help with data from the Swedish No-Fault Liability Insurance database. We also thank G&an Hallgren at the Swedish No-Fault Liability Insurance Company (TFA) for being helpful in contacts with the traffic insurance companies. The project has been financed by the Swedish Road Safety Office.
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Research Institute, Ann Arbor, MI 48 109-Z 150. Committee on Injury Scaling (1990) The Ahhrecinted Injzq
.%x/e, 1990 revision. Association for the Advancement 01’
Automotive Medicine, Des Plaines, IL. Evans, L. (1986)
The effectiveness of safety belts in preventing fatalities.
Accident Ancrh’sis and Pre:,ention
18.
229-241. Evans, L. (1991) Center high mounted stop lamps. In T&tic
Safety and the Dril:er.
ed. L. Evans, pp. l23-
126. Van
Nostrand Reinhold, New York. Evans, L. and Frick, M.C. (1993) Mass ratio and relative driver fatality risk in two-vehicle crashes. Accident Antrlwi.\ cmd Prewntion Evans, L. tlY94)
25, 213-224. Driver
injury and fatality risk in two-car crashes versus mass ratio inferred using Newtonian
mechanics. Accident Annlwis and Prevention 26, 609-616. Finnish Motor Insurers’ Centre (1993) Companies (VALT)
Occupants in taxis should buckle up. Traffic
(press release I1 November
Safety Committee of Lnsuranca
1997).
Folk och bostadsrakningen 1990 t 1991) Arbetsmarknad,
Statistiska Centralbyran (Labour Market, Official Statistics 01
Sweden). Insurance Group Reports (1995)
Insurance claims for sprains and strains increase, even as the number of crashe\
declines. (Status Report, Vol. 30, No. I ~January 14). Jar], T., Thorson. J. and &tman,
A.-M.
(1989) Traffic injuries to truck and bus occupants, Joumnl of Occupationa/
Accidents 11. 75-86. Jones. IS.
and Stein, H.S. (lY89J
Vehicle and driver factors in relation to crash involvement of heavy trucks. In
Proceedings of’ Strategic Hi,qhwo.v Resalrch
Program und Trofic
Safety on Two Continents, 27-29
September.
Gothenburg, Sweden. Luhin, S. and Sehmer, J. (1993)
Are automobile head restraints used effectively’? Canadian
F-umi/y Phwicicm
39.
1584-1588. Official
Statistics of Sweden (1992)
Occupational
diseases and occupational
accidents
1990. National
Board 01
Occupational Safety and Health Statistics, Stockholm tin Swedish). Dno, K. and Kanno, M. (1993) influences of the physical parameters on the risk to neck injuries in low impact speed rear-end collisions. In Proceedings of the Internationul
IRCOBI
Conference on Biomechanics of Impact.\, X-IO
September, Eindhoven, The Netherlands, pp. 201-212. Personskadekommitten
inom Fiirsakringsbranschens Serviceaktiebolag
(1989)
Grunder for gradering av kvarstiende
men efter skador (medicinsk invaliditet). (Principles for the assessment of permanent impairment after traumatic injury (medical impairment)). Robertson. L.S. (1992)
Stockholm (in Swedish).
Laws and format rules directed at individual behavior. In InjuT
Robertson, pp. 124-146.
Epidemiologv.
ed. L.S.
Oxford University Press, New York.
Strandberg, L. (1989a) On the braking safety of articulated heavy freight vehicles, (WI Traffic Research Institute, Linkoping, Sweden.
note 134J.: Swedish Road and
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Strandberg, L. (1989bl Braking characteristics of 400 heavy trailer combinations from Denmark, Finland, Norway and Sweden. (VT1 note 1351. Swedish Road and Traffic Research Institute, Linkijping, Sweden. Svensson, L. and Vidtn, S. (19941 Accident investigation, Accidents involving Volvo trucks resulting in driver injury, and the estimated effect of the SRS-Airbag. (Report 4).: Volvo Truck Corporation, Driver Environment and Road Safety Department, Gothenburg, Sweden. Svensson, M.Y. (1993) Neck-injuries in rear end car collisions. Dissertation. Department of Injury Prevention, Chalmers University of Technology, Gothenburg, Sweden, Nordisk Yrkesklassificering (1984) Svensk Grundstandard. The Nordic Classification of Occupations. Arbetsmarknadsstyrelsen 1983 Liber Tryck, Stockholm (In Swedish). Transportforskningsdelegationen (Transport Research Institute) (1979) Olyckor vid utryckningskorning. Transportforskningsdelegationen 1979: 10. Stockholm. Valverius, M., Moberg, J. and Linden, C. (1982) Roadside survey in Northern Sweden. In Proceedings of the Satellite Conference to the 8th International Conference on Alcohol. Drugs and Trajjic Safety, 23-25 June 1980. Umei, Sweden, pp. l-32.
Pergamon
PII: SO9257535(97)00042-S
OCCUPATIONAL ROAD TRAUMA AND PERMANENT MEDICAL IMPAIRMENT Per-O/of Bylund a,*, U/f Bjarnstig a, Tore J. Larsson b,c a Ume2 Accident Analysis Group, Department of Surgery, Umea University, S-901 85 UmeB, Sweden b Institute for Human Safety and Accident Research (IPSO), Stockholm, ’ University of Ballarat, Ballarat, Victoria, Australia
Sweden
Abstract-Medically impairing occupational injuries sustained in traffic in Sweden were analysed. More than half of the cases with a permanent medical impairment were caused by minor injuries. Soft tissue injuries to the neck (whiplash injuries) made up nearly half of all permanently impairing injuries, and half of these were caused by rear-end collisions. As a final result, just over one third (37%) of the total group had a permanent decreased work capacity, or needed to change jobs because of residual problems from their injuries. Professional drivers had the highest injury incidence per employed and they accounted for 28% of the total number of permanent impairment cases, and for 43% of the fatalities. Professional drivers also had a higher percentage of serious injuries and severe permanent impairments than other occupational groups. This might be associated with the low use of safety belts (16%) compared to other occupational groups, where usage was 4-5 times higher. This occupational injury problem ought to be handled in the same way as other occupational safety problems, i.e. protective equipment in a vehicle should be used and the use of safe vehicles should be encouraged. 0 1997 Elsevier Science Ltd
1. Introduction The total number of accidental deaths during work-time has decreased greatly in Sweden since the middle of the 195Os, from over 400 per year to approximately 100 (Official Statistics of Sweden, 1992). Vehicle-related injuries are today the largest individual cause of death in Swedish working life (Official Statistics of Sweden, 1992). Many professional groups besides professional drivers use motor vehicles in their work. Injuries sustained in traffic have not been looked upon as a work injury problem but rather as ‘traffic accidents’. Injuries giving rise to medical impairment probably have special characteristics. In a thorough review of the literature, we have not found any reports dealing with medically impairing injuries sustained in vehicle crashes in traffic during work-time.
* Corresponding
author.
[email protected].
Tel.:
+ 46-90-785
24 01;
fax:
+ 46-90-78.5
24 01:
e-mail:
188
The aim of this study is to analyse the epidemiology and consequences impairing injuries sustained in traffic during work-time for different occupation
P.-O.
Bylund
et al.
of medically groups.
2. Material and methods
Injuries sustained during work-time, in/on a registered motor vehicle, that resulted in permanent impairment (n = 466) or death (n = 40) were analyzed. The injury events occurred between 1 January 1988 and 31 December 1990 in Sweden. Data on these injuries were extracted from the Swedish Work-Related No-Fault Liability Insurance (TFA) database on 1 August 1993. This insurance, which is handled by a consortium of the largest insurance companies in Sweden, covers virtually all employed on the Swedish labour market, and pertains to almost all work-related injuries and diseases with more than seven days of sick leave. Bank tellers and finance clerks were not covered by this insurance system. The study does not consider injuries that occurred outside the general traffic area or on the way to or from work. A Swedish study (Bjornstig and Larsson, 1994) showed that about 90% of those injured at work, and suffering a permanent medical impairment, reported this to the insurance and compensation program. Injuries were classified according to the Abbreviated Injury Scale (Committee on Injury Scaling, 1990) where MAIS is Maximum AIS. Soft tissue injuries to the neck also named sprain, strain, distorsio colli (whiplash injuries) are referred to using the medical term distorsio colli. The amount of sick leave was calculated as the number of l/l days off work within two years after the crash. In Sweden, permanent medical impairment is defined in a Classification Manual used by the Insurance Industry (Personskadekommitten inom Fijrs’akringsbranschens Serviceaktiebolag, 1989). Medical impairment is a measure of the loss of body function as a result of injury and is expressed as a percentage. When the injury has reached a stable condition and there is no expectation of improvement, the exact medical impairment is determined on basis of an examination by a medical specialist. AIS, indicates the AIS-value of the impairing injury. In the case of multiple impairing injuries, AISi refers to the highest AIS,-value among the injuries in question. Injuries resulting in permanent impairment which had not received a final assessment from the insurance company by 30 June 1994 (3.5-6.5 years after the injury) (32; 7%) were, after a review of the appropriate journals and interviews, awarded an impairment level equal to the average for that type of injury. In one case it was too early to assess final level of impairment, which could not be more closely determined than 2 10%. The Nordic Classification of Occupations (Nordisk Yrkesklassificering, 1984) was used to allocate the cases according to occupation. The group professional drivers includes drivers of trucks, buses, taxis and delivery cars (NYK 640641). The total number of people working in each group was obtained from the Official Statistics of Sweden (Folk och bostadsrakningen 1990, 1992). The size of the vehicles was classified as: small/medium-sized cars (kerb weight ( 1250 kg), large cars (> 1250 kg), light cargo vehicles (< 3.5 tons; includes minibuses, vans, pick-up trucks and jeeps) and heavy trucks/buses (kerb weight 2 3.5 ton).
Occupational road trauma and permanent medical impairment
3. Results
3.1. Age, sex and position in the vehicle
Of the 506 injured, 40 sustained fatal injuries and 466 received impairing injuries; 442 (87%) had been driving the vehicle. A majority (365; 72%) were men. Nearly one fifth (n = 7) of those who died were women. The average age of the injured men was 41 years and of the women 39 years.
3.2. Incidence of injuries among different occupational
groups
Professional drivers, especially those driving delivery cars/light cargo vehicles and taxis had the highest injury incidence per employed among the different occupational groups (Table I>.
Table 1 Annual number of fatally occupational groups
injured,
medically
impaired
and injury
incidence
per 100000
employed
in different
Occupation
Fatally injured
Impaired
Incidence
Professional, technical and related work (NYK 001-009) Educational work (NYK 030-035 +037-039) Health and nursing work (NYK 100-109 + 154) Children nurses, pre-primary education teachers (NYK 153 + 036) Administrative, managerial and clerical work (NYK 200-299) Business service salesmen, shop assistants etc. (NYK 313-333) Agriculture, horticulture and forestry management (NYK 400-411) Busdrivers (NYK 640.10) Taxidrivers and passenger car drivers NYK (640.20-30) Truck drivers (NYK 641.10) Delivery car/light goods vehicle drivers (NYK 641.20) Mail sorting clerks and postmen (NYK 681) Messengers (NYK 682) Metal machine work and building metal work (NYK 75 l-759) Electrical and electronics work (NYK 761-765) Construction workers (NYK 791-799) Stationary engine operation work material handling (NYK 861-873) Firemen (NYK 901) Policemen (NYK 903) Watchmen (NYK 906) Caretaking and cleaning work (NYK 931-939) Conscripts (NYK x19) Other Unknown
5
6 3 2 2 2 3 4 40 114” 39 142 18 12 2 5 2 3 22 22 18 4 6
3 2
45 14 31 12 29 29 8 20 45 53 12 15 8 19 14 7 6 5b 11 6 18 8 50 1
Total
40
466
a One test driver is excluded in the estimation b Three firemen working as paramedics.
2 5 1
1 4 4 8 1 1
2
1
of injury incidens for taxi drivers.
_ 4
190
P.-O. Bvlund et al.
Table 2 Number of fatalities and permanently
medical impaired in different type of crashes
Crash mechanism
Fatally injured
Impaired
Total
Multi-vehicle
26 (65%)
330 (71%)
356 (71%)
18 7 _ _
107 120 78 20 5
125 121 85 20 5
8 (20%)
124 (27%)
132 (26%)
crashes (70%)
Frontal vehicle-to-vehicle crashes Rear impact by another vehicle Vehicle-to-vehicle side crash at intersection Crashed into the rear of another vehicle Other type of multi-vehicle crashes Single-vehicle
1
crashes (26%)
Crashes into stationary object Drove off the road and overturned Skidded and landed in a ditch Other type of single-vehicle crashes
4 2 2 _
Vehicle-train collisions (2%) Crashes involving game (1%)
5 (13%) 1(3%)
60%) 6 (1%)
11(2%) 7 (1%)
40 (100%)
466 (100%)
506 (100%)
Total
44 36 25 19
48 38 27 19
3.3. Type of crash Table 2 shows that front- and rear-end collisions were the most frequent. Single crashes accounted for more than one quarter of all injuries. For those travelling in heavy trucks, more than one fourth (19:66; 29%) were injured in collisions with other trucks or buses. One fifth (14:66; 21 %j of the heavy-truck occupants were injured in single-vehicle crashes when the truck turned over. In one case, a tank-truck driver drove into a ditch due to brake failure. More than a third (9:26; 35%) of those injured in a bus were injured when the bus collided with a truck or with another bus. At least six (7%) of the truck and bus occupants were ejected from the vehicle in the crash. In three crashes, taxi drivers were injured while operating the taximeter/computer when driving. 3.4. Crashes incoluing emergency
vehicles
A total of 23 people travelling in emergency vehicles were injured. Twelve policemen (six in cars, five on motorcycles and one in a minibus) were injured, two of them during ‘emergency driving’. Nine persons were injured in ambulances, five were ambulance personnel, three were nurses and one was a patient. Six of these were injured during ‘emergency driving’. Two firemen were injured, both during ‘emergency driving’. 3.5. Injury sever@ More than half (55%) of the 466 permanently impaired had only minor injuries (MAIS = I ), while 76 (16%) sustained serious (MAIS 2 3) injuries. Forty people died (MAIS = 5-6). Amongst the permanently impaired professional drivers of four-wheeled motor vehicles, 29 (22%) had MAIS 2 3 injuries, whilst in the other professions the number of (MAIS 2 3) injuries was lower (43; 13%).
Total
Fatal injuries
Multiple impairing injuries
Distorsio colli Fracture/luxation Lower extremity Upper extremity Fractured spine Sprain upper extremity Sprain and strain of the back Sprain lower extremity Brain, eye and other facial injury Other injury
Single impairing injury
injury
Impairing
140 (28%)
7
16
I
183 (36%)
14 7104%)
6
4
3 _
4 _
5 4
27
11 7 7 4 2 _
17 9 11 6 2 2
12 5 3 6
1
21
n = 61
91
n = 142
n= 117
Light cargo vehicle
80
Kerb weight > 1250 kg
car
Kerb weight I 1250 kg
Passenger
injury, fatalities and type of vehicle
Table 3 Impairing
92 (18%)
12
11
2 2
15 10 I 4 7
21
n = 69
Heavy truck/bus
13 (3%)
1
2
1
_ _ _
4 3 2 _
n = 10
Motorcycle
7 (1%)
_
1
_
I
2
_
I
_
2
n=6
Other/unknown
506 (100%)
40 (8%)
61(12%)
59 (12%) 35 (7%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) I3 (3%) 4 (1%)
221(44%)
n = 405
Total
P.-O. Bylund
192
3.6. Type of vehicle and permanent
et al.
medical impairment
The largest group of people had been travelling in large cars, but nearly a fifth had been travelling in heavy trucks or buses (Table 3). The ratio of fatalities to permanent impairment cases was twice as high for those travelling in heavy trucks or buses (12:80; 15%) as for those travelling in other four-wheeled vehicles (27:367; 7%). A majority (171; 66%) of the 259 car occupants with a single impairing injury sustained distorsio colli injuries. The proportion of extremity fractures was nearly the same among those injured in large cars (26; 18%) as among those injured in small- or medium-sized cars (17; 15%), but the number of people receiving fractures of the spine was nearly four times higher in large cars (n = 11) than in small- or medium-sized cars (n = 3). In heavy trucks and buses nearly half (32; 46%) of the 69 with a single impairing injury, sustained fractures of the extremities (n = 25) or spine (n = 7), while less than a third (21; 30%) sustained permanent impairment due to distorsio colli. 3.7. Permanent medical impairment, injury type and severity The impairment was caused by minor injuries (AIS, = 1) in more than half of the cases (27 1; 58%) (Table 4). Among these, 2 19 (8 1%) people sustained a distorsio colli injury and just over half (n = 114) of these were caused by rear-end impacts. Two thirds (81; 66%) of the 122 women and less than half (140; 48%) of the 291 men with impairing injuries had a distorsio colli diagnosis. Just over a quarter of the impairments were caused by a moderate injury (AIS, = 2). In this group, fractures and luxations of the lower and upper extremities were most common. Sixty-one people sustained multiple impairing injuries, often head injuries (n = 34) in combination with fractures (n = 2 1) and/or distorsio colli (n = 20). There was no difference noted in the age groups between minor and serious injuries.
Table 4 Distribution of AIS, among 465 cases.with AIS, classification) Impairing
injury
medical impairment.
(One person with a cold injury is excluded
AIS,
Total
1
2
3-5
Single impairing injury
261
108
35
Distorsio colli Fracture/luxation Lower extremity Upper extremity Fractured spine Sprain upper extremity Sprain and strain of the back Sprain lower extremity Brain, eye and other facial injury Other injury
219
2
Multiple impairing injuries
37 26 25 3
10 271 (58%)
221 (47%) 22 4 5
4 8
4
24
27
132 (28%)
404 037%)
62 (13%)
59 (13%) 35 (8%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) 13 (3%) 3 (1%) 61 (13%) 465 (100%)
in the
Occupational road trauma and permanent medical impairment Table 5 Impairing
injury and days of sick leave
Impairing
injury
Single impairing
193
Days of sick leave
injury
0
I-30
31-90
91-180
181-365
>365
Unknown
n= 35
n = 68
n= 87
n = 66
n=48
n = 98
It=3
fl=405
50
44
30
20
4-l
3
221 (47%)
3
9 14
12 10
14 2
24 3
_ _
6 4
3 2
4 2
7 3
10 5
_
1 3 1
6 3 6 _
1 3 2 2
1 1 _
4 _
-
3 2
_ _
59 (13%) 35 (8%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) 13 (3%) 4 (1%:)
8
6
7
8
32
-
61(13%)
Distorsio colli 27 Fracture/luxation Lower extremity 3 Upper extremity Fractured spine 4 Sprain upper extremity 1 Sprain and strain of the back _ Sprain lower extremity _ Brain, eye and other facial injury _ Other injury Multiple impairing
injuries
Total
Total
-
35(8%) 7606%)
9300%)
73(16%)
56(12%)
130(28%) 3(1%)
466 (100%)
3.8. Duration of sick leave Over half (32; 53%) of those with multiple impairing injuries and nearly one quarter (98; 24%) of those with a single impairing injury were on sick leave for longer than one year (Table 5). Of the latter, 47 (48%) had the diagnosis distorsio colli, 24 (24%) had a fracture/luxation of a lower extremity and 10 (10%) had a fracture of the spine. Twenty seven of those who had a distorsio colli injury had not been on sick leave the first two years after the injury. Distribution over age was the same for those with short- and long-term ( > 1 year) sick leave. 3.9. Degree of medical impairment from different injuries Twenty-two (36%) of the 61 with multiple impairing injuries had a severe medical impairment (2 20%), this was 4.5 times more often than those with a single diagnosis (31; 8%) (Table 6). Four of the 221 with the diagnosis distorsio colli had an impairment degree of 20% or more, which is higher than the normal 5-15% for this injury. There was no difference in the age distribution between those with severe (2 20%) and less severe levels of medical impairment. In four-wheeled vehicles, severe medical impairment ( 2 20%) was almost twice as common amongst professional drivers (21; 16%) as amongst those in other occupations, 3.10. Social consequences Over one third (170; 37%) of the 466 who sustained a medical impairment could not return full-time to their previous work (Table 7). Sixty-five (14%) had received a full-time early retirement on medical grounds, or were on full-time sick leave when the analysis was made, 3.5-6.5 years after the injury. The proportion who had retired or retrained was just as high for
194
P.-O. Bylund et al.
Table 6 Impairing
injury and degree of permanent
Impairing
injury
medical impairment
Degree of impairment
Total
l-4%
5-9%
IO-19%
20- 100%
Unknown
Single impairing injury
n = 56
?I = 201
II = 111
n = 31
n=O
Distorsio colli Fracture/luxation Lower extremity Upper extremity Fractured spine Sprain upper extremity Sprain and strain of the back Sprain lower extremity Brain, eye and other facial injury Other injury
23
126
68
4
221 (47%)
4 13 2 6 2 2 2 2
23 17 14 8 9 5 5 _
20 3 7 5
12 2 7
59 (13%) 35 (8%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) 13 (3%) 4 (1%)
3
23
Multiple impairing injuries Total
59 (13%)
230 (49%)
n = 405
2 2
I I _
2 2
4 _
12
22
1
61 (13%)
53 (12%)
1
466 (100%)
123 (26%)
those who had sustained fractures, as for those who had been diagnosed with a distorsio colli injury. Amongst those with multiple impairing injuries, 29 (48%) retrained or retired either full or part-time. Amongst the 405 with only a single impairing injury, 141 (35%) were retired or retrained. Of those in early retirement or on full-time sick leave, most (44; 68%) were in the 40-59 year age group and 17 (26%) were under 40 years of age.
Table 7 Impairing
injury and social consequences
Impairing injury
Full-time early retirement
Part-time early retirement
Retrained for another work
Back to previous work
Unknown
Total
Single impairing injury
n = 55
n = 35
?I = 51
n = 262
n=2
n = 405
Distorsio colli Fracture/luxation Lower extremity Upper extremity Fractured spine Sprain upper extremity Sprain and strain of the back Sprain lower extremity Brain, eye and other facial injury Other injury
27 13 _
23 5 _ 3 2 1 _ _
28 8 3 5 2 2 2
2 _ _
I
I
141 33 32 17 13 8 7 9 2
-
221 (47%) 59 (13%) 35 (8%) 30 (6%) 20 (4%) 14 (3%) 9 (2%) 13 (3%) 4(1%)
Multiple impairing injuries
10
I
12
31
1
61 (13%)
Total
65 (14%)
5 3 3 _ 4 _
42 (9%)
63 (14%)
293 (63%)
_ _ _
3 (1%)
466 (100%)
Occupational road trauma and permanent medical impairment n=133
195 n=65
n=169
100%1
n=60
I
25%
“_
SMALL/MEDIUM PASSENGER
LARGE PASSENGER
CAR
-
MAIW
CAR
m
LIGHT CARGO VEHICLE
MAIS=
n
BUS/HEAVY
TRUC IK
MAW3
Fig. 1. Injury severity and type of vehicle.
3.11. Severity of injury, impairment
and use
qf safety belts
The proportion of people with moderate or serious injuries (MAIS 2 2) was lowest amongst those travelling in small- and medium-sized cars, while the proportion was highest (50; 63%) in heavy trucks and buses (Fig. 1). Only 8 (6%) of those travelling in small- or medium-sized cars were severely (2 20%) impaired, while the proportion was highest (26; 15%) amongst those travelling in large cars (Fig. 21. Severe impairing injuries were twice as common (9:36; 25%) among taxi drivers as among other occupational groups (16:131; 12%) travelling in large cars. n-133 100%
n=65
n=169
n=60
r
75%
25%
0% SMALL/MEDIUM PASSENGER CAR
LARGE PASSENGER
Fig. 2. Medical impairment
CAR
LIGHT CARGO VEHICLE
BUS/HEAVY
degree and type of vehicle.
TRUCK
P.-O. Bylund et ~1.
196 n=133
n-65
n=169
n=80
100%
0% PASSENGER m
CAR Belted
PASSENGER
CAR
Unknown
VEHICLE
0
Non-belted
Fig. 3. Use of safety belt and type of vehicle.
The data relating to the use of safety belts is based upon information given by the people who survived the accident, as the police revealed safety belt usage in less than a third of the fatality cases. The use of safety belts was high (106; 80%) amongst the 133 who were injured in small- and medium-sized cars. Amongst the 80 travelling in heavy trucks or buses, only three drivers and one passenger were using safety belts (Fig. 3). Five of 23 occupants in buses were passengers. About a third (11; 31%) of the 36 taxi drivers travelling in large cars stated that they were using their safety belts at the time of injury. In one crash in which the taxi driver died, the paramedics found the safety belt fastened behind the driver’s back, apparently to turn off the safety belt warning light. The occupational groups dominated by civil servants and academics (158; 87%) complied best with the compulsory use of safety belts; those belonging to blue collar occupations had a lower compliance (81; 61%). Drivers of heavy trucks, buses and taxis were not included in this specific calculation, as they are exempt from the safety belt law.
3.12. Alcohol
Of the 40 occupants who died, 37 were drivers and 36 were tested for alcohol inebriation. Three (8%) tested positive with a blood alcohol concentration (BAC) of 0.3, 0.4 and 1.6 g/l, respectively. In another fatal crash, a motorcycle policeman died when he collided with a car which overturned. The car driver was inebriated. One surviving tank-truck driver suffered from delirium tremens during his hospital stay, caused by abstinence from alcohol. No alcohol blood test was performed in this case. Among all 466 injured, nine (2%) were injured when the other driver involved in the crash had, according to the police report, been under the influence of alcohol, or was suspected of driving while under the influence of alcohol.
Occupational
road waumu and permanent
medicnl
impuirmenr
197
4. Discussion
In proportion to the number of employed in each occupation, drivers of delivery cars/light cargo vehicles, taxis, buses and heavy trucks had the highest injury incidences. No exposure data was available for different groups of professional drivers, which makes a comparison on the risk per kilometre driven impossible to calculate. Bus and truck drivers also had the highest proportion of serious injuries and fatalities. This is noteworthy considering that they travel in vehicles that should be superior in most crash scenarios due to their weight (Evans and Frick, 1993; Evans, 1994). The predominant cabin design in Sweden (‘cab over’). however, places the driver near the front, and this could be a contributing factor to the unexpected result. This type of design is common in Sweden due to the current rules stipulating an overall maximum permissible length. These trucks are manufactured to maximize their carrying capacity, giving a minimal deformation zone. A change of regulations would might make it easier to build safe trucks. Light cargo vehicles have restricted deformation zones. and a somewhat old-fashioned design contributes to a lack of safety in these vehicles. An increased use of safety belts, introduction of air-bags and better deformation zones would make these vehicles safer. The tank-truck carrying petrol, which went off the road due to brake failure, could have caused a catastrophe. Failures in the brake systems of trucks are not uncommon (Jones and Stein, 1989; Strandberg, 1989a.b). Compulsory inspections, more than once a year, might be needed for heavy vehicles. Special problems are associated with the driving of emergency vehicles. A Swedish study has shown that the risk of injury was twice as high in ‘emergency driving’ as in ordinary driving (Transportforskningsdelegationen, 19791. Drivers of emergency vehicles often claim that other drivers fail to observe the emergency vehicle. dispite the use of blue emergency lights and sirens. Nearly half of the impairing injuries were distorsio colli injuries, but only half of them were caused by rear-end impacts. Other studies (Ono and Kanno, 1993; Lubin and Sehmer, 1993) show that, half and two-thirds, respectively, of all car crashes lead to neck injuries and that these injuries are increasing in frequency (One and Kanno, 1993). Improved head restraint design, clear information about the importance of correct adjustment of head restraints and high brake light placement (Evans, 1991) may reduce the incidence of this type of injury. Rigid rear tow bars mounted onto the frame of the car may also transfer unnecessarily strong impulses to the occupant seats in rear-end impacts, since they bypass the vehicle’s rear deformation zone. Measures to reduce the distorsio colli type of injury should be given a high priority. as long-term sick leave, early retirement and retraining are important consequences. How safety belt pretensioners and air-bags affect the frequency of these injuries sustained in frontal and side collisions remains to be determined. Interestingly, 27 people with distorsio colli were not on sick leave the first two years following the injury. This suggests that the symptoms became increasingly troublesome. However, the assessment routines within the Swedish Work Injury Insurance might also be relevant here and the high incidence of neck problems in the general population can make the association between cause and effect quite difficult to ascertain (Bovim et al., 1994). The social consequences were considerable. One third of those injured did not return to their previous work (half had been retired early on medical grounds and the other half received retraining). The economic consequences of these injuries are considerable as well. Neck injuries represent large pay-outs from the insurance
198
P.-O. Bvlund et al.
companies (Insurance Group Reports, 1995). In Sweden, this type of injury is reckoned to cost SEK 2 billion annually (USD 300 million) (Svensson, 1993). The use of safety belts by truck and bus occupants was low. It has been calculated that 27-60% of those injured in truck and bus crashes would have had less serious injuries if they had used a safety belt (Jar1 et al., 1989; Campbell and Sullivan, 1991; Svensson and VidCn, 1994). The risk of ejection, which can cause serious injuries, is eliminated with the use of safety belts. In the present study, at least 7% of those travelling in a bus or a truck were ejected from the vehicle. Other authors have cited higher figures (12-36%) (Jar1 et al., 1989; Campbell and Sullivan, 1991; Svensson and VidCn, 1994). An air-bag used in conjunction with a safety belt reduces injuries in heavy trucks (Svensson and Viden, 1994). Several studies have argued that in certain crash situations (accounting for perhaps 5-9% of all crashes), the use of safety belts would have worsened the injuries (Jar1 et al., 1989; Svensson and VidCn, 1994). In the present study, barely one third of the taxi drivers had been using the safety belts. The injury reducing potential is about 50% for both serious and fatal injuries (Evans, 1986; Campbell, 1987). A Finnish report suggests that safety belt use should be compulsory only when the taxi driver is alone in the vehicle (Finnish Motor Insurers’ Centre, 1993) since taxidrivers are said to fear being attacked by passengers in the car. The use of safety belts during travel in a vehicle during work-time should be considered as a question of occupational safety. As construction workers always wear helmets, drivers of cars, trucks and buses should wear their safety belts to protect themselves. In Sweden the employers have the responsibility for their employees safety and rehabilitation. A written contract between the employer and the driver, stipulating that the safety belt should be used when travelling in the company vehicles, would be one suggestion that might increase the safety belt use. However, a compulsory law for the driver groups today exempted from the belt law would be more efficient (Robertson, 1992). In the present study, 8% of the fatally injured drivers were driving under the influence of alcohol and in one surviving case, a tank-truck driver showed alcohol withdrawal symptoms during his hospital stay. Alleene et al. (1991) reported 13% drivers under the influence of alcohol in fatal occupational motor-vehicle crashes in the US. In Swedish traffic, the prevalence of alcohol inebriated drivers is about one per thousand (Valverius et al., 1982). Effective measures must be developed against alcohol and other drug use by drivers of trucks, especially those with dangerous loads. Today. the police in Sweden have no right to carry out routine tests for the use of illegal drugs other than alcohol, if there are no visible signs of inebriation. However, employers should consider regular and random alcohol and drug testing for drivers of dangerous goods vehicles. An independent company, agreed to by both employer and unions, could carry this out. Another method to consider would be to install ‘alto-lot’ on all heavy vehicles, especially those carrying dangerous loads.
5. Conclusions
Vehicle-associated injuries during work-time should be seen as an occupational safety problem. Optimal use of existing protective equipment should be encouraged, and the employer should provide vehicles with high safety standards. Measures for the prevention of distorsio colli injuries are of great importance.
Occupational
road trauma und permunent medical impairment
19’1
Acknowledgements The authors would like to thank Karin Torsteinsrud and Cecilia Oldertz at the Institute fog Human Safety and Accident Research (IPSO) in Stockholm for their help with data from the Swedish No-Fault Liability Insurance database. We also thank G&an Hallgren at the Swedish No-Fault Liability Insurance Company (TFA) for being helpful in contacts with the traffic insurance companies. The project has been financed by the Swedish Road Safety Office.
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