Epidemiology of Child Motor Vehicle Crash Injuries and Fatalities

Abstract

Although children represent only 10–15 % of the overall traffic fatality burden in the United States, motor vehicle crashes (MVCs) remain the leading cause of death and disability for children and young adults; and, close to half of all unintentional injury deaths to children and adolescents (Centers for Disease Control and Prevention National Center for Injury Prevention and Control, Web-based Injury Statistics Query and Reporting System [CDC NCIPC WISQARS] 2010). Moreover, their exposure to motor vehicle risk is significant because they travel by motor vehicles nearly as much as adults. Prevention of the fatalities, injuries and disability associated with MVC must be a priority for ensuring our children’s overall health.

Appendix-Data Sources and Methodology

NHTSA Field Crash Databases

To help the traffic safety community identify traffic safety problems, develop and implement vehicle and driver countermeasures, and evaluate motor vehicle safety standards and highway safety initiatives, the National Highway Traffic Safety Administration (NHTSA) developed a variety of field crash databases. Each has a specific purpose and role in the identification of vehicle safety issues and the assessment of countermeasures with the optimal cost/benefit. Many of the analyses described elsewhere in this chapter use these databases as their source of data and thus this description provides context for those studies. In addition, these databases represent resources for researchers to explore topics of motor crash injury for child occupants.

Fatality Analysis Reporting System

The Fatality Analysis Reporting System (FARS) was developed by NHTSA’s National Center for Statistics and Analysis (NCSA) in 1975 to assist the traffic safety community in identifying traffic safety problems and evaluating both motor vehicle safety standards and highway safety initiatives. FARS contains data on all fatal traffic crashes within the 50 states, the District of Columbia, and Puerto Rico. To be included in FARS, a crash must involve a motor vehicle traveling on a traffic way customarily open to the public, and result in the death of a person (either an occupant of a vehicle or a nonmotorist such as a pedestrian) within 30 days of the crash event.

FARS case files contain descriptions of each fatal crash reported. Each case has more than 100 coded data elements that characterize the crash, the vehicles, and the people involved. All data elements are reported on the following forms:

• The Accident Form collects information such as the time and location of the crash, the first harmful event, and the numbers of vehicles and people involved.

• The Vehicle and Driver Forms record data on each crash-involved vehicle and driver. Data include the vehicle type, initial and principal impact points, most harmful event, and drivers’ license status.

• The Person Form contains data on each person involved in the crash, including age, gender, role in the crash (driver, passenger, nonmotorist), injury severity, and restraint use.

Data are available for every year since FARS was established in 1975 and can be easily queried using a Web-based query system (http://www-fars.nhtsa.dot.gov/Main/index.aspx). To protect individual privacy, no personal information, such as names, addresses, or specific crash locations, is coded. It is important to realize that analyses using the FARS dataset are based on fatal crashes, which may differ in meaningful ways from the general spectrum of crashes on the roads.

National Automotive Sampling System

Established in 1979, the National Automotive Sampling System (NASS) was created as part of a nationwide effort to reduce MVCs, injuries, and deaths on our nation’s highways. It is composed of two systems—the Crashworthiness Data System (CDS) and the General Estimates System (GES). Both systems are based on cases selected from a sample of police crash reports. CDS data focus on passenger vehicle crashes, and are used to investigate injury mechanisms to identify potential improvements in vehicle design. GES data focus on the broader overall crash picture, and are used for assessments of the magnitude of a specific traffic safety problem and tracking trends. NASS-CDS and NASS-GES select cases from police crash reports [also known as Police Accident Reports (PARs)] at police agencies within randomly selected areas of the country. Data from GES and CDS are weighted in such a manner that statistical analyses using these weighted data can result in national estimates of the traffic safety topic being studied.

For NASS-CDS, field research teams located at Primary Sampling Units (PSU’s) across the country study ∼5,000 crashes involving passenger cars, light trucks, vans, and utility vehicles each year. About 200 of these crashes involve a child occupant. Trained crash investigators obtain data from crash sites, studying evidence such as skid marks, fluid spills, broken glass, and bent guard rails. They locate the vehicles involved, photograph them, document the crash damage using sophisticated measuring procedures, and identify interior locations struck by the occupants. These researchers follow up on their on-site investigations by interviewing crash occupants and reviewing medical records to determine the nature and severity of injuries. The data collected by the PSU’s are quality controlled by one of two NASS Zone Centers which have the responsibility for coordinating and supervising the activities of the field offices, keeping field offices informed regarding changes in functional and administrative procedures, sharing ideas and concepts throughout the system regarding new techniques, procedures, and components found on vehicles and updating field offices regarding changes in system hardware and software.

NASS-GES data comes from a nationally representative sample of police reported MVCs of all types, from minor to fatal. For a crash to be eligible for the GES sample it must involve at least one motor vehicle traveling on a traffic way, the result must be property damage, injury, or death and a PAR must be completed. These accident reports are chosen from 60 areas that reflect the geography, roadway mileage, population, and traffic density of the US GES data collectors make weekly visits to ∼400 police jurisdictions in the 60 areas across the United States, where they randomly sample about 50,000 PARs each year. About 10,000 of these crashes involve a child occupant. The data collectors obtain copies of the PARs and send them to a central contractor for coding. No other data are collected beyond the selected PARs. Trained data entry personnel interpret and code ∼90 data elements data directly from the PARs into an electronic data file. An annual publication, Traffic Safety Facts, is produced with GES data for nonfatal crashes, combined with information on fatal crashes from FARS. NASS-GES provides broad estimates of child crash exposures but with little data specific to children, especially on important parameters such as injury and restraint use. NASS datasets can be downloaded for analyses from NHTSA’s Web site (http://www.nhtsa.gov/NCSA).

Special Crash Investigations

Since 1972, NCSA’s Special Crash Investigations (SCI) Program has provided NHTSA with an in depth and detailed level of crash investigation data. The data collected ranges from data maintained in routine police and insurance crash reports to data from special reports by professional crash investigation teams. Hundreds of data elements relevant to the vehicle, occupants, injury mechanisms, roadway, and safety systems involved are collected for each of the more than 200 crashes designated for study annually.

SCI cases are intended to serve as an anecdotal dataset useful for examining special crash circumstances or outcomes from an engineering perspective. To this end, the inclusion criteria are changed routinely to address emerging traffic safety needs. The benefit of this program lies in its ability to locate unique real-world crashes anywhere in the country, and conduct in depth clinical investigations in a timely manner, which can be used by the automotive safety community to improve the performance of its state-of-the-art safety systems. Individual and select groups of cases have triggered both individual companies and the industry as a whole to improve the safety performance of motor vehicles, including passenger cars, light trucks, or school buses.

The SCI program’s flexibility allows for detailed investigation of any newly emerging technologies related to automotive safety. A number of incidents involving alternative fuel vehicles, passenger side air bag deployments, vehicle-to-pedestrian impacts, and child restraints have been investigated. A focus of the SCI program in the 1990s was investigation of cases of serious injuries and fatalities to children exposed to deploying air bags. Summary tables of these cases as well as any other cases the SCI program has investigated are available on NHTSA’s Web site (http://www-nass.nhtsa.dot.gov/BIN/logon.exe/airmislogon), as are copies of completed SCI reports.

Crash Injury Research and Engineering Network

In order to maximize the integration of crash data collected by engineers and crash reconstructionists with detailed injury and radiological information collected by clinical teams at hospitals, NHTSA has funded hospital-related studies since the 1980s. In 1991, NHTSA initiated the Highway Traffic Injuries Studies. Over the next several years, research projects were funded at four Level One Trauma Centers to collect detailed injury information on motor vehicle occupants involved in crashes. In 1996, the Crash Injury Research and Engineering Network (CIREN) was developed in response to the need for a uniform centralized data system when three additional Level I Trauma Hospitals were added to the network as part of a settlement agreement with General Motors.

CIREN is a sponsor-led multicenter research program involving a collaboration of clinicians and engineers in academia, industry, and government pursuing in-depth studies of crashes, injuries, and treatments to improve processes and outcomes. Its mission is to improve the prevention, treatment, and rehabilitation of MVC injuries to reduce deaths, disabilities, and human and economic costs.

There are not any CIREN centers focused specifically on children; however, all sites enroll children who present to their trauma centers. These child occupants are screened using criteria pertaining to specific vehicle and crash characteristics as well as the injury and restraint status of the child. Once a subject meets the criteria for enrollment and consents to participation in the study, an in-depth investigation is initiated to collect detailed crash and injury information. Traumatology experts review the occupant’s radiology and clinical data for the location and type of the injury. Crash investigators investigate the crash vehicles and the crash scene to determine the severity of the impact and the physical evidence of occupant’s interaction within the crash environment. Mechanical and biomechanical engineers experienced in the field of crash testing and biomechanics research evaluate each case to determine the role of the vehicle’s design and the level of interaction with the occupant. Together, these multidisciplinary teams of engineers and clinicians review the cases to assess injury causation scenarios and injury mechanisms. These data are publicly available and can be accessed by http://nhtsa-nrdapps.nhtsa.dot.gov/bin/cirenfilter.dll.

Partners for Child Passenger Safety

In 1998, researchers at Children’s Hospital of Philadelphia and State Farm Insurance Companies responded to a need for a crash surveillance system focused exclusively on children and created the Partners for Child Passenger Safety (PCPS) Study. Based on many of the design specifications of the NHTSA databases, PCPS data have been used to conduct many of the child-focused analyses that are discussed in this chapter. In place from 1998 to 2007, PCPS consisted of a large-scale, child-specific crash surveillance system: insurance claims from State Farm functioned as the source of subjects, with telephone survey and on-site crash investigations serving as the primary sources of data. Durbin et al. (2001c) described the study methods in detail.

Briefly, passenger vehicles qualifying for inclusion were State Farm-insured, model year 1990 or newer, and involved in a crash with ≥1 child occupant <16 years of age. Qualifying crashes were limited to those that occurred in 16 states and the District of Columbia, representing three large regions of the United States. A stratified cluster sample was designed to select passenger vehicles (the unit of sampling) for the conduct of a telephone survey with the driver. Probability sampling was based on two criteria: whether the vehicle was towed from the scene and the level of medical treatment received by the child passenger(s). For a subset of crashes of specific interest, in-depth crash investigations were conducted using a similar methodology to the SCI program.

International Data Sources

Several countries outside the United States have championed in-depth crash investigation programs to understand child occupant injuries. Examples of these programs are featured in several studies highlighted elsewhere in this chapter. A partial list of these programs includes the following:

• Child Restraint System in Cars (CREST) and Child Led Injury Design (CHILD)—European collaborative research projects (http://www.childincarsafety.org)

  • The CREST project (1999–2000) and the CHILD project (2002–2006) were European Union funded research efforts focused on child safety that involved a consortium of European industry, government and academic entities. As part of these projects, over 800 in-depth crash investigations involving child motor vehicle occupants were conducted. A subset of these in-depth investigations was reconstructed as full-scale vehicle to vehicle crash tests. A third project in this series, Child Advanced Safety Project for European Roads (CASPER) was started in 2009.

• Cooperative Crash Injury Study (CCIS)—United Kingdom (http://www.lboro.ac.uk/research/esri/vehicle-road-safety/projects/ccis.htm)

  • Based at Loughborough University, the CCIS study started in 1983 and investigates more than 1,200 crashes annually. The study selects a sample of cases involving newer vehicles which are representative of crashes occurring in the UK. Both adult and pediatric motor vehicle occupants are studied.

• German In Depth Accident Study (GIDAS)—Germany (http://www.gidas.org/en/home)

  • Officially started in 1999, GIDAS collects crash and medical data through in-depth investigation from ∼2,000 cases annually in two cities in Germany—Hanover and Dresden. Cases are chosen based on a statistical sampling plan from crashes reported to police, rescue services and fire departments in the targeted areas. Both adult and pediatric motor vehicle occupants are studied.

• International Road Traffic and Accident Database (IRTAD) (http://www.irtad.net)

  • IRTAD, started in 1988, is a database that houses traffic fatality data from many countries throughout the world. It is maintained by the International Traffic Forum and the Organization for Economic Co-operation and Development. At present the following countries are included: Australia, Austria, Belgium, Canada, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Japan, Korea (South Korea), Luxembourg, the Netherlands, New Zealand, Norway, Poland, Portugal, Sweden, Switzerland, Spain, Slovakia, Slovenia, Turkey, Hungary, the United States, the UK. It serves as an important resource in comparing road safety metrics between various developed countries.

• Volvo’s statistical crash database—Sweden—(Jakobssen et al. 2005)

  • Volvo has compiled a crash database from crashes involving their vehicles identified through a Swedish Insurance company. Vehicle damage information is sent to Volvo’s in-depth crash investigation team and injury data is gathered from medical records. Several publications have focused on the child occupants that are in this privately held database.

Each of these research efforts has varied objectives and data collection methods, which make it difficult to merge the data for analysis. They do however represent rich sources of detailed data on child occupant injury.