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| Journal of the New Zealand Medical Association,
16-December-2005, Vol 118 No 1227
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Work-related fatal traffic crashes in New Zealand:
1985–1998 Bronwen McNoe, John Langley, Anne-Marie Feyer
The annual rate of acute unintentional fatal injury in New
Zealand is 26.0 per 100,000 person per year.1 About half of these fatalities
occur as the result of motor vehicle traffic injury.1 Work-related injury also
contributes substantially to the overall injury burden. In New Zealand, two
studies have attempted to describe the extent of work-related fatalities,
neither have included traffic fatalities.2,3 The more
recent, the Work-Related Fatal Injury
Study, determined the rate of fatalities due to work-related activity was 5.03
per 100,000 workers.3
We have identified two population-based studies that report
on work-related traffic fatalities. The first was in Australia and identified
that 37% of work-related fatal injury was due to motor vehicle traffic injury.4
The second study was in the United States and found that roadway crashes
accounted for more than 23% of workplace fatalities.5 When bystanders to work (a
person who is killed as the direct result of someone else’s work activity)
are included, these figures are likely to increase further. Current priorities
and strategies for injury prevention in New Zealand are established without a
good understanding of work-related traffic injury.
Currently agencies responsible for routine injury data
collection in New Zealand cannot provide accurate estimates of the number of
work-related traffic crashes or fatalities in New Zealand. New Zealand Police do
not identify in their Traffic Crash Report whether crashes were work-related or
not. Crashes involving commercial vehicles are identified, but some of these
commercial vehicles may have been used for non-work activity at the time of the
crash.
The notifications database maintained by Occupational Safety
and Health (OSH) and the national compensated claims database maintained by the
Accident Compensation Corporation (ACC) do not provide an adequate base from
which to estimate the extent of the problem because of reporting and coverage
issues.6
If a similar situation exists in New Zealand to the United
States and Australia, where the largest single category of work-related
fatalities is traffic injury, then the absence of accurate information on the
number and circumstances is a major barrier to developing priorities for injury
prevention.
The aim of this study was to identify and describe all
work-related traffic vehicle fatalities that occurred on a public road in New
Zealand between 1985 and 1998 inclusive. This paper describes the methods used
in the study and gives a synopsis of the overall findings obtained. Other papers
provide an analysis of bystander deaths as well as an international comparison
of work-related traffic fatalities between New Zealand, Australia, and the
United States.
MethodsThe methodology adopted in this study closely followed
that in a similar Australian study4 so as to allow meaningful comparisons. A
work-related traffic case was defined as a person who suffered a traumatic death
that occurred in New Zealand and involved a traffic vehicle, to which workplace
exposures contributed as a necessary factor to the death, and which can be
attributed to those exposures. A traffic vehicle was defined operationally as a
conveyance in which, any person or property may be transported on a public road.
In other words, this study was not confined to incidents involving motor
vehicles but also includes transportation such as push bikes. Work-related
activity encompassed most aspects of work, including working, commuting,
activity during a recess period (e.g. lunch break), at an employer sponsored
social function, and during training or a non-work period if the incident arose
because of work.
Three sources of data were used to identify potential
deaths due to a “traffic crash” that occurred in New Zealand between
1985 and 1998. The New Zealand Health Information Service (NZHIS) maintains a
record of all injury deaths within New Zealand. Those records classified with an
external cause code (E-code) of traffic incident or similar (E810-E829,
E846-E848, E919) were identified as potential cases.
The Land Transport Safety Authority (LTSA) maintains a
database that contains the official police records of reported motor vehicle
traffic crashes in New Zealand. All motor vehicle traffic fatalities in that
database were initially identified as potential cases. The Accident Compensation
Corporation administers New Zealand’s Accident
Compensation Scheme, which provides no-fault accident insurance for all New
Zealand citizens, residents, and temporary visitors to New Zealand. All
work-related fatal traffic crashes resulting in Accident Compensation
Corporation entitlement claims were identified from the Accident Compensation
Corporation motor vehicle account as potential cases. The death must have
occurred between 1 January 1985 and 31 December 1998. Exclusions from the study
included those aged over 85, suicide deaths, domestic violence, persons
performing home duties, criminal activity as work, and delay of greater than 1
year between the incident and death.
The absence of a
work-related identifier in any of the three data sources referred to above
necessitated the use of an alternate source of information to identify
work-related fatalities. For this study, the primary source of data to determine
work-relatedness for this study was from coronial inquest files. Certain deaths,
including unnatural deaths are notifiable to the police and the coroner. The
role of the coroner in these cases is to establish the cause and manner of death
by way of a coronial inquest. Although work-relatedness of an incident is not
required, in many instances information recorded within the coronial file can be
used to make a determination of work-relatedness.
From the three source databases, 12,519 potential cases
were identified. These were electronically matched by the victims’ name to
the coronial register, which contains a list of decedents name, date of birth,
and coronial inquest number. The commercially available data linkage software
Automatch7 was used for the matching
process. Cases that remained unlinked were hand matched, where possible, with a
coronial number. The matching process produced 10,993 coronial numbers (88%). It
is likely that some duplication existed within the remaining 1,526 files given
that three data sources were used. Of the 10,993 names, coronial files were
identified for 10,809 (98%) of potential cases.
Each identified file was requested in a random sequence
from Coronial Services at the Department of Justice where coronial files are
stored. Demographic details (name, age, sex, date of death) from the source
databases were checked against the coronial file to ensure a correct match had
been made.
Due to variation and inaccuracies in the format and
spelling of names, both in the databases and on the coronial register, the
matching process was, at times, imprecise. Up to three attempts were made to
match the correct coronial file. Of the potential cases identified, 98% were
correctly matched to a coronial file number. A further 15 cases that had not
been identified by the source databases were identified from within coronial
files reviewed. Each potential case identified was reviewed for
work-relatedness. Deaths were classified as definitely work-related, possibly
work-related, definitely not work-related, and indeterminate. The files for all
cases identified as definitely or possibly work-related were photocopied and
transferred to the study headquarters for further assessment.
Victims were classified as one of the following:
worker, commuter, and bystander to work.
Definition of a
worker:
“Persons
who work for pay, profit or payment in kind, in a job, business or on a farm,
and persons who worked without pay in a family business or on a farm”.
This includes employees, employers and self-employed persons, working full time,
part-time and ad-hoc hours.
“Persons
who worked in an official volunteer capacity for an
organisation”.
“Students,
who comprised any person who was studying and whose death was the result of an
incident, that occurred during school time, while they were performing a task
directly connected with their course”.
Definition of a
commuter:
“People
who satisfied the workers definition, but died as a result of an incident that
occurred while travelling directly from home to work, work to home, or between
two jobs. If the incident occurred while the person was travelling in the course
of their work duties, the person was not classified as a commuter but as a
worker”.
Definition of a
bystander:
“All
persons who were killed directly as a result of someone else’s work
activity, even though the deceased was not working at the time”.
Cases were coded in random order by three coders over a
5-month period. Demographic details of the deceased, circumstances surrounding
the injury, and work details (such as industry in which fatality occurred) were
some of the details recorded on worker or commuter fatalities. Because of the
large number of bystanders and the lack of detail in the coronial files on the
working component of the crash, bystanders were simply counted, the type of
vehicle involved in the crash recorded, and (when available) the active
contribution of working activity to the crash noted.Variables pertinent to the
analysis presented here include: gender, age, occupation (coded according to the
New Zealand Standard Classification of Occupations 19968) and industry (coded
according to the Australian and New Zealand Standard Industrial Classification
19969).
Inter- and intra-rater reliability was assessed for
both case determination and the coding of coronial files using a sample of
cases. For case review, there was 97% agreement, both between coders and by
coders over time. High levels of agreement also existed for the coding of
coronial files, for most variables being higher than 90%. The two exceptions to
this were for industry and occupational coding. The lower level of agreement
between coders for industry and occupation (80–86%) was of concern. To
ensure a higher level of reliability, every work-related coronial file was thus
re-reviewed for occupation and industry, and corrections made where necessary.
Data were analysed using Statistical Procedures for the
Social Sciences (SPSSx) software. Population rates per 100,000 person years and
95% confidence intervals were calculated (assuming a Poisson distribution). For
the purposes of deriving rates, census data were used to approximate the number
of persons of working age who were exposed to the road traffic environment,
while at work, or when going to or from work. It was assumed that everyone in
the working population could be exposed.
Estimates of the exposed population were available by
gender, age group, ethnicity, occupation, and industry. Census data were
available for 1986, 1991, 1996, and 2001, with the population in the intervening
years being determined by interpolation using a linear function for the
inter-census years to span the time frame 1985 to 1998 inclusive. The number of
workers in each level were summed over time to give an estimate of person-years
at risk.
ResultsThe total number of coronial files reviewed was 10,809 for
which 4034 files (37%) contained insufficient detail to make a work-related
determination.
This study identified 234 incidents resulting in 241 deaths
where the deceased was engaged in work-related activity on a public road, and a
further 183 incidents resulting in 192 deaths where the deceased was commuting
to or from work on a public road. In addition, although not engaged in work
themselves, 1447 people died in the process of another person’s work
activity on a public road (bystanders). This paper describes worker and commuter
fatalities only.
The overall rate of work-related traffic fatalities of
workers and commuters on a public road, between 1985 and 1998, was 2.01 per
100,000 workers per year. This was comprised of decedents working 1.11 and
commuting 0.89 per 100,000 workers per year. No obvious trend in either category
was apparent over the period studied.
The majority of the work-related traffic fatalities were
male, for both decedents working (93%) and commuting (80%). The highest number
of worker deaths occurred in the 25–34 year age group (n=64, 27%). The
highest number of commuter deaths was in the 15–24 year age group (n=68,
35%). Nearly three-quarters of worker deaths (n=172, 71%) occurred between age
20 and 49. Nearly three-quarters of the commuter deaths occurred under age 40
(n=138, 72%). The mean age was substantially lower for commuter fatalities (33
years) than for worker fatalities (39 years).
The age-specific rates differed for worker and commuter
fatalities (Figure 1). For workers, the rate of fatal injuries increased with
increasing age group, with the highest rate observed in the 65–84 year age
group. For commuters, the rate of fatalities declined with increasing age group,
with the highest rate observed in the 15–24 year age group.
The only information relevant to the nature of the work,
which was consistently available in the coronial files was that on the industry
and occupational group of the decedents.
For decedents working, the highest number and rate of fatal
injuries occurred in the transport and storage
industry (10.1 per 100,000 workers per year) which accounted for about
40% of the fatalities (Table 1). The sub grouping
road freight transportation had a
relatively high number of workers killed (n=83), with a correspondingly high
rate (33.7).
Although the number of fatalities was small, high rates were
observed in milk vending (19.4),
road and bridge construction (8.8),
postal and courier services (6.5),
plumbing services (6.3), and
taxi and other road passenger transport
(excluding bus transportation) (6.2).
Commuting fatalities were more evenly spread across a number
of occupations. The highest numbers of fatalities occurred in manufacturing
(n=36) as well as agriculture, farming, and fishing (n=33) (Table 1). The highest rates were observed in
livestock farming (7.6),
log saw milling (7.6),
automotive repair and service (4.5),
services to agriculture (4.2),
plumbing services (4.2),
horticulture and fruit growing (2.6),
and meat processing (2.4).
Figure 1. Age-specific rates (95% confidence interval)
for fatal work-related traffic injuries: 1985–1998
 The pattern observed in occupational groupings was similar
to that of industry (Table 2). For the worker group,
the highest number (with rates approximately 17 times the population overall)
occurred in the plant and machine operators
and assemblers, most notably to drivers
and mobile machinery operators (111 deaths) with a rate of 21.8 per
100,000 workers (Table 1). Within this group high rates were observed in
heavy truck or tanker drivers (28.6),
light truck and van drivers (15.1), and
taxi drivers (12.4).
Agricultural/earthmoving and equipment
operators also had high rates (9.1) particularly
‘earthmoving machinery
operators’ (14.1) and
roading/paving machine operators
(38.6). Other occupations that had significantly higher rates of fatal injuries
than the total working population were
couriers and deliverers (10.7), and
commercial travellers and sales
representatives (4.9).
For commuters, the highest numbers of fatalities occurred in
the plant and machine operators and
assemblers and the agricultural
forestry and fishing occupations. In the plant and machine operators, the
deaths were predominantly to stationary
machine operators and assemblers (20 deaths) and in the agricultural
industry to market orientated agricultural and
fishery workers (34 deaths) and market
orientated animal producers (17 deaths).
The relative importance of work-related traffic crashes to
other work-related injury is important in terms of prioritising areas for injury
prevention interventions. Previous comparable work estimated was that
approximately 75 deaths (excluding traffic crashes) occurred due to work-related
activity each year.3,10 In the present series we estimated an average of 31
(worker and commuter deaths) per year. In total then we estimate there were an
average of 106 work-related deaths per year. Therefore, an estimate of the
contribution of work-related traffic crash (worker and commuter deaths) to the
annual overall burden of work-related fatal injury was 29%. This estimate ranged
between 24% and 40% for particular years in the time period studied.
DiscussionAt an average of 31 deaths per year, work-related traffic
crashes represent the single largest category of work-related death in New
Zealand. Even if commuters are excluded from the estimate, the average is
approximately 17 deaths per year and this still represents a major contributor
to the annual burden of work-related death of approximately 100 per year.
Because of the difficulties associated with case ascertainment, the estimates
produced are likely to be a conservative, particularly for commuting incidents
that are more difficult to identify from coronial files than worker fatalities.
This in part is due to the lack of uniformity of recording systems for coronial
findings throughout New Zealand.11Direct comparisons of these results with
findings elsewhere need to be treated with caution because of differences
between national collections including different case definitions and case
ascertainment procedures. One of the major differences is the inclusion in this
study of commuter fatalities. In broad terms, however, similar patterns are
observed in this study to those found elsewhere in the developed world namely
that traffic injury generally forms the largest category of work-related
death5,12–15 and the most common industry in which traffic injuries occur
is road transportation 5,14,16–19.
Work-related traffic fatalities were found to be
predominantly male for decedents working and commuting. This large portion of
male deaths may be due to a number of factors. Firstly, it may reflect exposure.
Males are undertaking nearly twice the number of commuting journeys as
females16. Males also typically dominate many of the occupations involving
professional driving. Secondly, a bias may exist in the data, where the work
component is more explicitly stated in the coronial file for males than for
females. Finally, particularly in occupations such as forestry and fishery
(where workers are predominantly male), it seems likely that commuting is
undertaken at riskier times of the day or for longer periods. The highest number
of commuting fatalities occurred in the agricultural forestry and fishing
industry and in the manufacturing industry. This may reflect that these workers
are commuting longer distances at riskier times of the day. In these industries,
many workers start work early in the morning and will therefore travel to work
at their circadian low points and may well be at risk for fatigue-related
crashes.
Rates of work-related traffic injury in this study were
relatively constant between ages 15 and 64 but rose markedly over the age of 65.
However, the confidence intervals around the later estimates suggest it should
be viewed with caution. In terms of raw numbers, approximately two-thirds of
working decedents were under the age of 45.
The lower numbers of occupational fatalities observed
amongst older workers in this study may reflect the age distribution of driving
occupations. As professional drivers age, they may be likely to move from the
road to static workplace-based positions that are less physically demanding,
thus decreasing their exposure to road incidents. For example, a cohort study
conducted on professional drivers in the Scandinavian countries demonstrated
that over a 10-year period, about one-quarter of the cohort had changed tasks
within their trade (for example, from bus driver to supervisor). A further
quarter had left their trade altogether.17
Age may have a detrimental effect on risk of occupational
injury in that some particular tasks, such as some physically demanding
activities and continuous rapid information processing, decline in older age
groups. Conversely, age may afford the
opportunity for greater experience on the road, which will benefit tasks that
require experience and refined skills.5,18
The number and rate of commuting incidents was highest in
the 15–24 year age group and declined with increasing age. Nearly
two-thirds (64.1%) of decedents commuting were under the age of 44. This may
reflect driver behaviour in those age groups. Young people always feature
prominently in crash statistics whether they are commuting or not. It may be
that young people travel longer distances because they enjoy driving, because
they need to travel further to obtain work, or because of where they live, all
of which would increase their exposure.
There is likely to be an overestimate of risk based on
populations. Data on the number of driver hours exposed are not available but it
is likely that a risk estimate based on these denominator would be different to
that based on a population. For example, truck drivers will spend more hours on
the road than plumbers. In New Zealand, currently there is no routine
surveillance of work-related traffic injury nor even any means of systematically
and simply identifying events. New Zealand’s changing employment
climate—including the increasing casualisation of the labour force,
variable working hours, and multiple job handling—may effect the rate of
work-related injury on the road, but current data collection processes will be
unable to detect this. Therefore, it is important that relevant agencies have a
good understanding of this problem so that they can accurately and effectively
identify and prioritise areas for work-related injury prevention.
This study has enabled an estimate of the burden of
work-related traffic injury to New Zealand but because of delays in the
availability of coronial files the information provided is not particularly
timely and was very resource intensive to produce given the number of coronial
files that needed to be manually reviewed. An added problem was that the
information contained in coronial files often does not provide much (if any)
information on the work-relatedness of the fatal incident.
Since all injury deaths are investigated by the coroner, the
coronial system provides an obvious means of determining whether a death was
work-related. A Bill (Coroners Bill) is currently before the New Zealand
Parliament that proposes a major reform to the coronial system.
This provides an excellent opportunity to put in place
uniform systems for identifying important classes of death such as work-related
deaths and capturing key features of these deaths in a uniform manner.
Author information:
Bronwen McNoe, Assistant Research Fellow; John D Langley, Professor and
Director, Injury Prevention Research Unit, Department of Preventive & Social
Medicine, Dunedin School of Medicine, University of Otago, Dunedin;
Anne-Marie Feyer, Director, Health Risk, Management Practice, Price Waterhouse Pty Ltd, Sydney, Australia Acknowledgements:
This research was supported by the Health
Research Council of New Zealand. The assistance provided by the Department of
Courts, in particular Craig Leahy (Coroners Clerk), was also invaluable. In
addition, we gratefully acknowledge our colleagues on the study team including
Shaun Stephenson (Biostatistician); Nicola Dow (Data Manager); Dorothy Begg
(Research Adviser); Jane Bishop, Rebbecca Lilley and Patricia Virtue (Junior
Research Fellows); and James Falconer (Research Assistant).
Correspondence: John
Langley, Injury Prevention Research Unit, University of Otago, PO Box 913,
Dunedin. Fax: (03) 479 8337; email: john.langley@ipru.otago.ac.nz
References:
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