Pregnant Crash Test Dummies: Rethinking Standards and Reference Models

The Challenge

Conventional seatbelts do not fit pregnant women properly, and motor vehicle crashes are the leading cause of fetal death related to maternal trauma (Weiss et al., 2001). Even a relatively minor crash at 56km/h (35 mph) can cause harm. With over 13 million women pregnant across the European Union and United States each year, the use of seatbelts during pregnancy is a major safety concern (Eurostat, 2011; Finer et al., 2011).

Method: Rethinking Standards and Reference Models

The male body is often defined as the norm and serves as the primary object of study. In this case, crash test dummies were first developed to model the U.S. 50th percentile man (taken as the norm). This means that other segments of the population were left out of the “discovery” phase in design. Inattention to humans of different sizes and shapes may result in unintended harm.

Gendered Innovations:

1. Taking both women and men as the norm may expand creativity in science and technology. From the start, devices should be designed for safety in broad populations.
2. Analyzing sex has led to the development of pregnant crash dummies and computer simulations.

The Challenge
Method: Rethinking Research Priorities and Outcomes
Method: Rethinking Standards and Reference Models
Gendered Innovation 1: Changing Established Standards
Method: Analyzing Sex
Gendered Innovation 2: Pregnant Computer Crash Models
Conclusions
Next Steps

The Challenge

In engineering design, men are often taken as the norm; women (as well as smaller men) are analyzed as an afterthought and often studied from the perspective of how they deviate from the norm. As a result, many devices are adapted retrospectively to women.

Crash Test Dummy Development

• 1949: Test dummies were first developed for the U.S. Air Force‚Äîsee image (Advisory Group, 1996).
• 1966: The VIP (Very Important People) group of test dummies was developed. This group consisted of 3 dummies, modeling the 5th percentile woman, 50th percentile man, and 95th percentile man. The VIP group was the first set of test dummies used in standardized automotive testing (Advisory Group for Aerospace Research and Development, 1996).
• 1972: The Hybrid II, a new generation of dummy, was developed by General Motors to model the 50th percentile male body. The U.S. Federal Motor Vehicle Safety Standard 208 specified this male dummy for use in compliance testing from 1973 to 1997. New generations of dummies consistently innovated using the midsize adult male as the norm. This dummy was subsequently scaled to represent both the 5th percentile female and 95th percentile male populations.
• 1980s: Test dummies modeled children (3 and 6 years of age). Infant dummies (6, 12, and 18 months old) were developed in 1990.
• 1996: A pregnant crash test dummy was created by researchers at the University of Michigan Medical Center, in conjunction with General Motors and the National Highway Traffic Safety Administration (NHTSA). The aptly named MAMA-2B (Maternal Anthropomorphic Measuring Appliance, version 2B) used the small 5th percentile female Hybrid III crash dummy with a pregnancy insert, complete with a model uterus, amniotic fluid, and a 28-week fetus (Pearlman et al., 1996). Patents have been issued for both the pregnant crash test dummy and the specialized sensors for collecting data from pregnant dummies (Elhagediab, 2009).
• 2012: Pregnant crash test dummies are not yet used in government-mandated auto safety testing in the U.S. or by the European New Car Assessment Programme (NHTSA, 2008)‚Äîsee Methods below.

Method: Rethinking Research Priorities and Outcomes

Test dummies were first developed for the U.S. Air Force in 1949. Women were excluded from major combat roles in the armed forces at this time, so the male body was given priority in the design of military safety technologies. This bias, however, was not corrected when test dummies were developed for civilian use—where both women and men have urgent safety needs.

View General Method

Method: Rethinking Standards and Reference Models

The design of crash test dummies improved significantly over the period from 1949 to 1996. In the 1970s, the majority of dummies modeled only the 50th percentile male. By the 1980s and 1990s, a wider range of dummies—representing diverse heights and weights—were utilized in vehicle safety tests. By expanding the modeling base, engineers took the safety of women, men, and multi-ethnic populations into consideration: Dummies represented both the largest of the large (i.e., the 95th percentile man) and the smallest of the small (the 5th percentile female). This modeling was later expanded to include children of different ages and weights.

View General Method

Gendered Innovation 1: Changing Established Standards

In the 1970s European automobile makers began to lose market share to foreign (primarily Japanese) companies, because many foreign cars better “fit” small people in European populations. This led European engineers to take a new look at women and other populations when designing cars (see Method).

Over time, reference standards for crash safety testing have become more inclusive. The U.S. Code of Federal Regulations first specified the use of a 50th percentile male dummy in 1973, but expanded testing guidelines to include the use of a 5th percentile female dummy in 2000 (U.S. Code of Federal Regulations, 2011).

Method: Analyzing Sex

While developing anthropomorphic dummies, researchers noted that women's normal seated position differed from what was defined as the standard seating position. Women on average tend to sit closer to the steering wheel to compensate for shorter stature, which puts them at greater risk for internal injury in frontal collisions (Augenstein, 2005). The notion that persons of small stature are out-of-position drivers implies that the problem is the smaller-than-the-norm driver. In fact, the problem resides in the technologies (i.e. car seats and settings) that have not been proportioned to take the safety of all drivers into consideration. Analyzing sex may improve product usability and safety.

View General Method

Gendered Innovation 2: Pregnant Computer Crash Models

Pregnant crash test dummies are used to test seatbelts and other safety features in automobiles. Seatbelts were first installed in automobiles in the 1950s, and their use became mandatory in the late 1980s and early 1990s. As early as 1967, the American Medical Association advocated the use of seatbelts by pregnant women based on the notion that both the mother and fetus were safer with a standard 3-point seatbelt than with no seatbelt (Committee, 1972). At that time, little laboratory research in seatbelt design for pregnant women existed, making it difficult to assess the comparative effectiveness of various seatbelt designs and other safety technologies, such as the airbag (Insurance Institute for Highway Safety, 1972). As seatbelt usage increased, injuries caused by lap belts began to raise concerns that seatbelts might be hazardous to the fetus even when mothers were not injured (Committee, 1972).

Current research suggests that pregnant women should use the 3-point seatbelt (McGwin et al., 2004), yet for many women, particularly those who carry low, 3-point seatbelts ride up on the pregnant belly. In a crash, this increases force transmission to the abdomen by three- or four-fold relative to the force transmitted when the belt is worn below the uterus—with a corresponding increased risk of fetal injury (Pearlman et al., 1996).

Gendered innovations in the development of pregnant crash test dummies and computer simulations have the potential to play a key role in increasing seatbelt safety for pregnant women.

While improvements to the pregnant crash test dummy (the MAMA-2B created in 1996) are ongoing, in 2002, researchers in the U.S. adapted crash simulation software to model a pregnant female with a virtual uterus, placenta, and amniotic fluid as well as uterosacral and round ligaments (Moorcroft, 2003). Using this computer model, validated by cadaver and real-world crash data, researchers modeled differences in outcomes between unbelted, belted, and improperly-belted pregnant passengers. In 2008, developers further improved this computer model by adding a realistic 38-week fetus (developed using ultrasound images) and modeling in utero fetal motion during impact (Acar et al., 2009).

In 2002, Volvo also developed a virtual pregnant crash dummy "Linda"—in her 36th week of pregnancy (Bührer et al., 2006; Schraudner et al., 2006). Other car companies have also adopted computer models in their safety testing.

Conclusions

Gendered Innovations have led to more inclusive standards for crash test dummies. Female crash test dummies came into development in the late 1960s, yet pregnant test dummies did not become a research priority until the 1990s—some forty years after test dummies were first developed. Making pregnancy a research priority in automobile research and testing can lead to greater vehicle safety overall.

Next Steps

1. The U.S. NHTSA currently requires safety testing using dummies modeling women’s bodies, but not pregnant women. The European New Car Assessment Programme (Euro NCAP) utilizes the same Hybrid III dummies as prescribed by the U.S. NHTSA, and as a result does not model pregnancy in crash tests (Euro NCAP, 2010; Euro NCAP, 2009). Governments should mandate vehicle safety testing using pregnant crash test dummies or simulations.
2. The traditional 3-point seatbelt can harm a fetus. Redesigning seatbelts to accommodate pregnancy may need to become a priority for automobile makers. Private developers have introduced supplementary devices to hold conventional lap belts in place. The Maternity Seat Belt™ is just one example of a seatbelt repositioning device—but these have not undergone rigorous government safety testing (Klinich, 2009). A better solution may be a redesign of the conventional 3-point seatbelt to provide greater safety for all passengers.

Conventional seatbelts do not fit pregnant women properly, and motor vehicle crashes are the leading cause of fetal death related to maternal trauma. Even a relatively minor crash at 56km/h (35 mph) can cause harm. With over 13 million women pregnant across the European Union and United States each year, this is a major safety concern.

Gendered Innovation:

Crash test dummies were first developed in 1949. Pregnant crash test dummies first appeared in 1996, allowing researchers to model the effects of high-speed impact on the womb, placenta, and fetus. In 2002, Volvo developed a virtual pregnant crash test dummy "Linda"—in her 36th week of pregnancy (see image). Using computer models, validated by cadaver and real-world crash data, researchers studied differences in outcomes between unbelted, belted, and improperly-belted pregnant passengers. In 2008, developers further improved this computer model by adding a realistic 38-week fetus (developed using ultrasound images) and modeling in utero fetal motion during impact.

Next Steps:

1. Governments can mandate vehicle safety testing using pregnant crash test dummies or simulations.
2. The traditional 3-point seatbelt can be redesigned to accommodate pregnancy. This would enhance public safety and potentially be a profitable innovation for an entrepreneur.