NHTSA’s study of 1997 death certificates
was successful in locating a small number of certain types of non-traffic
or non-crash motor vehicle-related deaths. That study also confirmed
death certificates’ value as a source for identifying non-traffic
and non-crash motor vehicle-related deaths. There were inherent limitations
of the data in the study 1997 death certificates, however. Although
the criteria for selecting death certificates for review were carefully
chosen, there was no way of knowing for certain whether or not all of
the death certificates reflecting non-traffic or non-crash deaths had
been identified and if not, what percentage of the total was represented
by those found. Even among death certificates received, there were some
that suggested that a non-traffic or non-crash incident was involved,
but this could not be confirmed based on the information in the death
certificate, and in some cases even after the appropriate coroner or
other official was contacted. Finally, there was no way of knowing whether
or not the number of incidents found for just one year was indicative
of the ongoing magnitude and scope of a hazard or whether the snapshot
of data from one year might be contradicted by data derived from another
year or years, or from another source or sources.
In the broadest and simplest sense then, the
methodology for the research reflected in this report was to collect
whatever data was available on the non-traffic and non-crash motor vehicle-related
hazards of interest from whatever sources were available. The sources
in which relevant information was found for each of the issues are indicated
Carbon Monoxide: death certificates,
LexisNexis™, literature review
Backing: death certificates, LexisNexis™, FARS,
literature review, injury databases (NEISS and GES)
Vehicle Heat: death certificates, LexisNexis™,
Vehicle Window: death certificates, LexisNexis™,
The totals of non-traffic and
non-crash motor vehicle-related incidents located in death certificates,
LexisNexis™ and some of the other sources reviewed for this study
represent simple counts of relevant incidents. While there were no hard
and fast rules that applied to identifying relevant cases, incidents
involving particularly unusual events were excluded from the counts.
As an example, if a person were backed over by a vehicle that was left
running, in reverse, and unattended, this case was excluded from the
count of backing incidents.
The specific methodology that applied to each
of the types of sources investigated is described below.
1998 Death Certificates
State laws require death certificates to be
completed for all deaths. Furthermore, federal law mandates national
collection and publication of death and other vital statistics data.
As a result, and as confirmed by the study of 1997 death certificates
conducted by NHTSA, death certificates represent a reliable and comprehensive
source of information regarding non-traffic and non-crash motor vehicle-related
deaths, particularly if information is entered for all of the key elements
of a death certificate and if the certificate includes at least some
description of how the injury that resulted in death occurred.
As it did in researching 1997 death certificates,
NHTSA’s Office of Crash Avoidance Standards contacted and met
with representatives of the NCHS to solicit their help in researching
1998 death certificates. NCHS publishes annual reports of all deaths
in the United States using information derived from death certificates.
Among other information, each death is assigned various codes that identify
the disease or condition directly leading to death, antecedent causes,
and other significant medical conditions involved.
For the year 1998, the underlying cause of death,
and the other specific injuries, diseases, and conditions related to
a death are classified and coded using the International Classification
of Diseases, 9th Revision (ICD-9). ICD-9 is designed for the classification
of morbidity and mortality information for statistical purposes, for
the indexing of hospital records by disease and operations, and for
data storage and retrieval. ICD-9 also contains a supplementary classification
of external causes of injury (E-Codes) that permits the classification
of environmental events, circumstances, and conditions as the cause
of injury and other adverse effects.
NHTSA identified what it considered to be the
ICD-9 codes, primarily E-Codes, most likely to be indicated on death
certificates reflecting one of the non-traffic or non-crash motor vehicle
issues included in this study. Clearly, not all deaths assigned ICD-9
codes suggestive of these conditions involve non-traffic or non-crash
motor vehicle-related events. In addition, deaths of interest may have
been coded, for various reasons, with codes other than those on which
this research focused. However, deaths associated with the ICD-9 codes
identified for this research represented a universe of deaths that would
most likely contain deaths resulting from the non-traffic or non-crash
injuries being studied.
In June of 2002, NHTSA met with NCHS officials
to discuss NHTSA’s review of the public use Multiple Cause of
Death (MCOD) data, the annual data file containing information derived
from all U.S. death certificates, and how to proceed with the study
of 1998 death certificates. It was agreed that the same protocol followed
for the study of 1997 death certificates would be followed for purposes
of obtaining 1998 death certificates. The seven steps of the protocol
- Submission of materials by NHTSA to NCHS reflecting the purpose of
the study and how information on the death certificates would be used.
- Submission of NHTSA’s materials to the National Association
for Public Health Statistics and Information Systems’ Executive
Committee for review and approval.
- Assistance to NHTSA from NCHS in identifying the selection criteria
from the information available in the electronic files with special
attention paid to the injury codes.
- The submission by NCHS of a request to each state for permission
to release the death certificate numbers to NHTSA in support of this
- Release of death certificate numbers to NHTSA by NCHS as states agreed
- NHTSA’s submission of a request to each state asking for copies
of death certificates (by identifying number), including any applicable
fee for the service. In the request, NHTSA stated that it would under
no circumstances attempt to contact family members of the decedents.
In some cases additional paperwork and state level approvals were required
for research of this sort.
- NHTSA’s review of death certificates, taking precautions to
protect all information obtained from them. States consider both the
death certificate numbers and the identifying information on the certificates
to be confidential, and are sensitive to the risk of “identity
Research involving death certificates
necessarily creates a substantial gap between the year in which the
deaths involved occurred and the time when the research is completed.
This gap is largely the product of the time it takes for NCHS to receive
and assemble data from the states and finalize its annual MCOD file.
Typically, the most recently completed MCOD file is two years or more
older than the year in which it becomes publicly available. In addition,
considerable time is required to complete the process described above.
Some states add another step to this process by requiring detailed paperwork
and state review board approvals, which are above and beyond the initial
approvals required to obtain death certificate numbers.
NHTSA initiated and followed the recommended
protocol. NCHS staff reviewed a NHTSA suggested list of selection criteria
for the non-traffic and non-crash motor vehicle issues to be studied
and proposed some additional selection criteria. Table I provides the
E-Codes, code descriptions, associated issues and any other data filters
that were used in identifying the more than 15,000 death certificates
of initial interest to the study.
Table I: E-Codes Used in
Locating Death Certificates
For Use in National Highway Traffic Safety Administration Research of
Non-Traffic and Non-Crash Deaths in 1998
1. Children left in a vehicle’s passenger compartment in hot weather
or who lock themselves in the trunk of a vehicle,
2. Children strangled by a vehicle’s power window or sunroof,
3. Persons killed or injured as a result of a vehicle backing up, (Backing)
4. Persons killed or injured as a result of vehicle-generated carbon
Motor vehicle traffic accident involving collision
Noncollision motor vehicle traffic accident while
boarding or alighting
Other noncollision motor vehicle traffic accident
Motor vehicle traffic accident of unspecified nature
Other motor vehicle nontraffic accident involving
collision with moving object (pedestrian)
Other motor vehicle nontraffic accident involving
collision with stationary object
Other motor vehicle nontraffic accident while boarding
Other motor vehicle nontraffic accident of other and
Accidental poisoning by other utility gas and other
carbon monoxide – motor vehicle exhaust gas
Due to lack of air (in closed place)
Vehicle heat/ trunk
Accidental mechanical suffocation – Other specified
Less than 9 years old
Accidental mechanical suffocation – unspecified means
Less than 9 years old
Caught accidentally in or between objects
Less than 9 years old
Assault by poisoning – other gases and vapors
Only records also with N986
Only if N986 or N992 is also present
Poisoning by other gases, undetermined whether accidentally
or purposely inflicted – motor vehicle exhaust gas
Hanging, strangulation, or suffocation, undetermined
whether accidentally or purposely inflicted
Hanging, strangulation, or suffocation, undetermined
whether accidentally or purposely inflicted – Other specified
Hanging, strangulation, or suffocation, undetermined
whether accidentally or purposely inflicted – Unspecified means
Injury by other specified means, undetermined intent
N Codes for Use
With Selected E-Codes as Additional Filters
Toxic effect of carbon monoxide
For use in selected circumstances (noted above) in
combination with an E-Code
Effects of heat and light
For use in selected circumstances (noted above) in
combination with an E-Code
The MCOD file includes a variable
for the “Underlying Cause of Death” and variables for up
to 20 injuries or diseases that may have contributed to the death. In
the language of the MCOD file, these are called “Record Axis Conditions.”
NHTSA expected that deaths caused by non-traffic and non-crash motor
vehicle-related injuries would be a subset of those with codes for the
underlying cause of death, but records were also examined according
to the 20 record axis conditions. In addition to searching the underlying
cause of death and other conditions using the ICD-9 codes in Table I,
certain data filters, also reflected in Table I, were imposed. A search
of 1998 death certificate data was limited to children less than 9 years
of age for E-Code 913.8, 913.9 and 918. These E-Codes were intended
to identify victims of strangulation by power window. The search using
E-Code 962.2 was limited to those records also containing an N-Code
(nature of injury code) of 986. Finally, for E-Code 968.4, the search
was limited to those records also containing an N code of either 986
Using the public use version of the MCOD file,
NHTSA made some preliminary calculations as to the number of death certificates
that might include people who died in a non-traffic or non-crash motor
vehicle-related event. Depending on the E-Codes and other criteria used,
it was determined that the number of death certificates that might reflect
incidents of the type under study exceeded 15,000. In contrast, only
1,792 death certificates were identified as being of interest for the
study of 1997 death certificates. The bulk of the increase in the 1998
death certificates resulted from the inclusion of backing incidents
as an area of study. The E-Codes that were likely to reflect backing
incidents were sufficiently broadly defined that it was clear they included
a wide range of other, more common motor vehicle crashes as well.
At an average price per death certificate on
the order of $8 to $9, it was strongly felt, and budgetary constraints
required, that every effort be made to minimize the number of death
certificates that ultimately would be requested from the 50 states,
the District of Columbia and New York City.
A large percentage of the deaths included in
this number were likely from conventional traffic crashes because the
E-Codes 814-825 are used in death certificates for a wide spectrum of
motor vehicle crashes. For example, “E-Code 822.7 – Other
motor vehicle non-traffic accident involving collision with moving object
(pedestrian)” – would apply to non-traffic vehicle and pedestrian
accidents in which a vehicle was moving either forward or backward.
Those involving the forward motion of a vehicle were not part of this
NHTSA representatives on several occasions discussed
with NCHS representatives possible ways of reducing the number of death
certificates to be obtained. The focus of those discussions was on how
to eliminate from the death certificates that would be requested from
the states those that would clearly not be of interest to this study
because they resulted from traffic crashes that did not involve backing.
In most cases, motor vehicle-related deaths from the MCOD file that
were initially identified as being of possible interest to the study
would actually not be of interest if they were also contained in FARS
because the vast majority of deaths in FARS do not involve backing.
Combining the electronic version of the MCOD
file with other data is not permitted by NCHS. So that NHTSA could eliminate
deaths identified in the NCHS MCOD file that were clearly the result
of crashes that did not involve backing, the Office of Rulemaking printed
out some basic data from this death certificate file. Death certificate
numbers were not in the file used and therefore were not included in
the data printout. The Office of Rulemaking also printed out some basic
data from the more than 40,000 deaths contained in FARS for 1998. Using
these printouts, data were manually compared and, as a result, a large
number of deaths from the list of death certificates of interest were
eliminated. Most deaths in the MCOD file that also appeared to be in
FARS were eliminated from further consideration. However, if FARS data
indicated that the crash involved a pedestrian and the first point of
impact was the rear of the vehicle, these deaths were included in those
for which death certificates were requested since a backing incident
relevant to the study was strongly suggested. Some deaths were retained
among those of interest, particularly if a pedestrian was involved,
even though there was no data to suggest a backing incident was involved.
The researchers wanted to eliminate those deaths that clearly were not
of interest, but also wanted to be sure to leave in those with even
a remote possibility of being relevant.
Some states (a small number) were delayed in
granting NCHS permission to allow NHTSA to receive death certificate
numbers. As a result, some death certificates were not requested from
some of the states in time for those certificates to be included in
the data presented in this report. The exact number of death certificates
that would have been requested from those states is not known. However,
it was estimated that if all certificates of interest had been received
from all of the jurisdictions, the total number of certificates would
have been approximately 5,500. As of the date of this report, 4,729
death certificates have been requested from 44 states and the District
Counts of incidents of any type from death certificates
represent a floor as to the number of incidents that actually occurred.
Deaths of interest may not have been coded according to the selection
criteria chosen. Also, death certificates are often very sketchy in
the descriptive information they provide. Limited follow up with medical
examiner’s and other offices thus far has uncovered backing incidents,
for example, that were not clearly identifiable from death certificates
alone. In some cases, information on a death certificate strongly suggests
it is an incident of interest, but the medical examiner’s office
and even the police agency involved were unable to clarify the situation.
Not all death certificates requested have been
received, nor is it anticipated that death certificates from every jurisdiction
will be received. As of the writing of this report, NHTSA has received
and reviewed 4,046 death certificates from 36 jurisdictions, 35 states
and the District of Columbia. Data from these death certificates, excluding
personal identifiers and certificate numbers, has been entered into
The 36 jurisdictions that provided death certificates
for this study represent a good cross section of states. They reflect
a balanced mix of characteristics, such as urban and rural, cold climate
and warm climate, and geographic regions of the country.
Straight-line projections of anticipated national
totals are made in this report using the number of deaths found in 1998
death certificates. A simple ratio was used to account for the missing
death certificates. The ratio was determined from the number of certificates
selected and received (5,500/4,046=1.36).
The researchers believe that projections from
the available data are reasonable estimates and reflect the magnitude
and scope of the hazards studied because of the balanced mix of the
states that provided death certificates. Had those states been skewed
toward warmer climates, for example, this might have had an effect on
the projected national totals of vehicle-related carbon monoxide deaths
since these incidents tend to happen in colder climates during the winter
To support this research, NHTSA subscribed to LexisNexis™ so that
it could search for news articles related to the four types of motor
vehicle-related hazards under study. A variety of words and phrases
likely to be associated with these hazards were used to conduct searches
LexisNexis™ served several purposes. When
a death certificate was suggestive of a type of incident under study,
but not conclusive, an article in LexisNexis™ sometimes confirmed
the nature of the incident so that it could be included or excluded
from this study. Sometimes, articles in LexisNexis™ identified
incidents from 1998 that were not located in 1998 death certificates.
Also, LexisNexis™ identified incidents from years beyond 1998.
References to LexisNexis™ derived data
or information appear in various contexts in the data and information
presented in this report. In the case of some death certificates, an
article found in LexisNexis™ either confirmed the nature of the
incident or provided additional information concerning that incident.
In such cases, this is indicated. A count of the incidents that have
occurred in the five completed calendar years, 1998-2002, and that were
located in LexisNexis™ is presented in this report. For the year
1998, the number of LexisNexis™ identified deaths that were also
found in death certificates is indicated. For the years 1999-2002, data
presented are derived solely from LexisNexis™.
It should be emphasized again here that the
cases identified through LexisNexis™ only represent a count of
cases. It is very clear from experience with LexisNexis™ that
many cases of interest to this research are either not reported in news
outlets or not included in LexisNexis™ because the news outlets
in which such cases might be reported are not included in the universe
of outlets from which LexisNexis™ draws.
Unlike either death certificates or FARS, as
described immediately following, articles found in LexisNexis™
report on both deaths and injuries. Therefore, LexisNexis™ derived
data presented in this report include injuries.
Fatality Analysis Reporting System
NHTSA’s Fatality Analysis Reporting System
(FARS) focuses on fatalities from vehicle crashes that occur on public
roads. FARS is a count of the annual national total of fatalities resulting
from vehicle crashes on public roadways. FARS represented a potential
source of backing incidents since backing incidents may occur off-road
or on a public road.
Among the various bits of data noted and entered
into the FARS database is the point on the vehicle at which the first
impact relating to the incident occurred. An examination of FARS data
relating to pedestrian fatalities that occurred in 1998 identified a
number of incidents in which a pedestrian was first struck by the rear
of the vehicle involved. In other words, cases were identified in FARS
with a high probability of being backing incidents of the sort of interest
to this research.
As described previously, this was helpful in
being sure to select for review certain 1998 death certificates whose
data matched a FARS record in which the rear of the vehicle was the
first point of impact. It also demonstrated that FARS contains backing
incidents of the sort under study.
Since backing incidents were found in FARS for
1998, FARS data was examined to identify potentially relevant backing
incidents that occurred in years later than 1998. FARS is created from
data that are derived from Police Accident Reports (PARs) that are reviewed
to identify deaths from vehicle crashes that are appropriate to include
in FARS. The rules governing FARS require that PARs from the two most
recently completed calendar years plus the current year be retained.
Older PARs are typically destroyed. FARS data was examined for possible
backing incidents in late 2002. At that time, the years for which PARs
were still available were 2000 and 2001.
A search of FARS data for the years 2000 and
2001 located 91 apparent backing fatalities in 2000 and 67 in 2001.
States were requested to provide the PARs for these incidents. A total
of 138 for the two years were received. Thirty-six of the incidents
reflected in the PARs received and reviewed were not entered into the
NHTSA database of non-traffic and non-crash cases because they involved
situations outside the scope of the research, such as an incident involving
an unusual vehicle like a small front end loader. A few of the 36 were
not entered because either the quality of the photocopy or the limited
information provided was such that what exactly happened could not be
Fourteen (14) backing deaths identified in FARS
had been previously identified through other sources, usually LexisNexis™.
The remaining 88 deaths had not been found in other sources. Even though
FARS focuses on deaths from vehicle crashes that occur on public roads,
many of the backing incidents in FARS occurred in driveways or other
off-road locations similar to those found in 1998 death certificates
and in other sources. These incidents may have been included in FARS
because the circumstances were ambiguous as to exactly where the incident
took place or they ultimately involved a public roadway in that the
vehicle and/or the victim ended up in a public roadway.
Peer-Reviewed Scientific, Medical and Public Health Journals
A review of scientific, medical and public health
research literature dealing with the issues being investigated was begun
using PubMed, an on-line service of the National Library of Medicine
that provides access to the library’s MEDLINE. MEDLINE contains
more than 12 million life science and public health article citations
dating back to the mid-1960's. In most cases, only abstracts are provided
so several trips to the National Library of Medicine in Bethesda, MD
were made to examine and, when necessary and appropriate, make copies
of full articles relevant to the issues covered in this report.
The National Electronic Injury Surveillance System (NEISS)
For nearly 30 years, the U.S. Consumer Product
Safety Commission (CPSC) has operated this statistically valid injury
surveillance and follow-back system. The primary purpose of NEISS has
been to provide timely data on consumer product-related injuries occurring
in the U.S. Beginning in 2000, NEISS was expanded to collect data on
all injuries, including those involving a motor vehicle. Collection
of information on this more broadly defined universe of injuries began
as of July 1, 2000. NEISS provided valuable information on backing injuries.
NEISS injury data are gathered from the emergency
departments of 100 hospitals. These hospitals are selected as a probability
sample of all 5,300+ U.S. hospitals with emergency departments. A “trauma
weight” is determined for each case in NEISS. According to the
CPSC, when there are 20 or more cases of a particular type of incident,
one may add the trauma weights for those incidents to come up with a
projection as to the number of such incidents that occur nationally
in a given year. When there are fewer than 20 incidents of a given type,
the CPSC indicates that the national projections that one derives from
these trauma weights are less reliable statistically.
As part of this round of research, NHTSA obtained
finalized NEISS data for the last six months of 2000 and preliminary,
although close to finalized data for the first six months of 2001. This
was the most recent data available when this research was conducted.
This year’s worth of NEISS data was searched
for young children who were left in a hot vehicle, trapped in a trunk,
or caught by a power window. It was also searched for backing incidents.
Backing was the only area in which multiple cases of injuries were found.
A total of 265 possible backing incidents were
located in NEISS. The text fields in each record were reviewed to determine
which of the incidents actually involved incidents of the type under
NHTSA’s General Estimates System (GES)
Data for the General Estimates Systems (GES)
come from a nationally representative sample of police reported motor
vehicle crashes of all types, from minor to fatal. The system began
operation in 1988. It was created to identify traffic safety problem
areas, provide a basis for regulatory and consumer initiatives, and
support cost benefit analyses of traffic safety programs. The information
is used to estimate how many motor vehicle crashes of different kinds
take place, and what happens when they occur. Although various sources
suggest that about half the motor vehicle crashes in the country are
not reported to the police, the majority of these unreported crashes
involve only minor property damage and no significant personal injury.
By restricting attention to police-reported crashes, GES concentrates
on those crashes of greatest concern to the highway safety community
and the general public.
A search of GES data for the years 1996 to 2000,
the most recent data available when the search was done, was conducted
to identify GES records for which non-occupant impact was the first
harmful event in the crash, with damage to the rear of the vehicle as
the initial impact and with vehicle role and maneuver consistent with
backing. Incidents were identified that allowed for national projections
of backing incidents. There was no language describing what occurred
in the incidents that could be reviewed. So the national projections
may include backing incidents of a type, such as vehicle rollaways,
that are outside the scope of this study.
Health Care Utilization Databases of the Centers for Disease Control
Several databases related to health care utilization
maintained by the National Center for Health Statistics (NCHS) of the
Centers for Disease Control and Prevention seemed like strong candidates
for providing good information on the issues under study. They were
not. Information derived from these databases applicable to the non-traffic
and non-crash injuries considered for this report was extremely limited.
The CDC databases exist to measure large indicators
of how health care resources in the United States are utilized, such
as the extent to which health care resources are used by various age
groups, the payers involved in obtaining health care, or the types of
treatments, therapies and drugs that are employed nationally. In short,
the databases are aimed at big picture issues, not more narrow subjects
such as non-traffic and non-crash motor vehicle-related safety issues
that involve small numbers of occurrences annually.
The databases do offer a limited opportunity
to identify incidents involving non-traffic and non-crash motor vehicle-related
safety concerns and for getting a very generalized (non-statistical)
sense of the relative magnitude of certain non-traffic and non-crash
motor vehicle-related hazards. That opportunity exists in the text fields
for each record in the databases. Unfortunately, information is not
always entered in these text fields and the information that is entered
is not always descriptive enough to determine exactly what happened
to cause an injury. For example “MVA,” referring to a motor
vehicle accident, sometimes appears as the only thing entered in the
text field of a record.
Unintentional injuries, which are how each of
the types of incidents in this study would be characterized, are a subset
of the data contained in each of the CDC databases. By searching the
text fields of unintentional injuries in the databases for certain words
likely to be used in describing an injury resulting from the issues
under study, several relevant incidents were located. However, because
the number of incidents found was so few, reliable national projections
of the numbers of these types of incidents could not be made. The CDC
databases generally require at least 30 incidents of a given type before
statistically reliable national projections about the incident type
can be made.
Each of the CDC databases examined is briefly
National Ambulatory Medical Care Survey
The National Ambulatory Medical Care Survey
(NMACS) is a national sample of patient visits to office-based physicians
who are not employed through the federal government and who are primarily
engaged in direct patient care. The survey, which includes specialists,
is conducted annually. The opportunity to gain some insights into how
an injury occurred is in a small text field on the survey form called
“cause of injury.”
The NAMCS determines a “patient visit
weight” for each record in this database. This represents the
projected total number of office visits that occurred across the country
and that are similar to the particular record involved. The patient-visit
weights for all of the records in the NAMCS sample indicate that there
were a total of 823,541,999 physician office visits in the year 2000
involving physicians of the type included in the NAMCS. National projections
for subcategories of office visits, by age group for example, may also
be tallied with varying degrees of statistical confidence. If there
are less than 30 records in any subgroup, national projections are considered
less reliable statistically.
NHTSA examined the NAMCS data file for the calendar
year 2000, the latest year for which survey results were available when
research for this report was conducted. That file contains 27,369 records,
of which 3,042 relate to an unintentional injury. Of the 3,042 unintentional
injury records, 994 contained no text in the “cause of injury”
field. A review of the 2,148 records with entries in the “cause
of injury” field located one record of interest to this study.
That was an incident in which the “cause of injury” was
given as “mother backed car over child,” in this case a
three year old. With only one record of a backing incident identified,
the “patient visit weight” of 3,983 for that incident was
of little or no predictive value.
National Hospital Ambulatory Medical Care Survey
The National Hospital Ambulatory Medical Care
Survey (NHAMCS) collects data on the utilization and provision of ambulatory
care services in hospital emergency and outpatient departments. Findings
are based on a national sample of visits to the emergency and outpatient
departments of non-institutional general and short-stay hospitals, exclusive
of federal, military, and Veterans Administration hospitals, located
in the 50 States and the District of Columbia. Annual data collection
began in 1992.
As with the other CDC databases, the text fields
of each record were searched to locate incidents of interest that are
included in the database.
The 2000 NHAMCS file for emergency department
visits contains 25,622 records, 8,791 of which are for unintentional
injuries. The text fields of the unintentional injury records were searched
for certain words that would likely be used in describing one of the
types of non-traffic or non-crash motor vehicle-related incidents under
study. A total of five incidents involving a vehicle backing up were
found in the NHAMCS emergency department file. Details of those incidents
are provided elsewhere in this report.
The outpatient portion of the NHAMCS for the
calendar year 2000 file has 27,510 records, 3,002 of which relate to
an unintentional injury. As with the emergency department records, the
text fields of the outpatient department unintentional injury records
were searched for certain words that would likely be used in describing
one of the types of non-traffic or non-crash motor vehicle-related incidents
under study. No records of injuries reflecting the types of hazards
under study were found in the search of this file.
National Hospital Discharge Survey
The National Hospital Discharge Survey (NHDS)
has been conducted annually since 1965. It is a national probability
survey designed to meet the need for information on characteristics
of inpatients discharged from non-Federal short-stay hospitals in the
United States. The NHDS collects data from a sample of approximately
270,000 inpatient records acquired from a national sample of about 500
hospitals. Only hospitals with an average length of stay of fewer than
30 days for all patients, general hospitals, or children’s general
hospitals are included in the survey. Federal, military, and Department
of Veterans Affairs hospitals, as well as hospital units of institutions
(such as prison hospitals), and hospitals with fewer than six beds staffed
for patient use, are excluded.
This database proved to be of no use since it
does not contain a text field for describing the circumstances that
led to the patient being hospitalized in the first place.