Wanted: Obese crash test dummies

U. BUFFALO (US) — Obese drivers have a higher chance of dying in a severe auto accident. So, should crash tests be conducted with dummies that reflect an increasingly overweight population?

“Crash test dummies have saved lives and provided invaluable data on how human bodies react to crashes, but they are designed to represent normal-weight individuals. If they represented our overweight American society, there could be further improvements in vehicle design that could decrease mortality,” says Dietrich Jehle, professor of emergency medicine at the University at Buffalo and first author of a new study reported in the American Journal of Emergency Medicine.

Jehle and colleagues found that a moderately obese driver faces a 21 percent increased risk of death, while the morbidly obese face a 56 percent increased risk of not surviving. Interestingly, underweight and normal weight drivers were found to be at higher risk of dying from a severe crash than slightly overweight drivers.

“The severity and patterns of crash injuries depend on a complex interaction of biomechanical factors, including deceleration velocity at impact, seat belt and air bag use, vehicle type and weight, and type of impact,” says Jehle, “but the effect of body mass on crash outcome has not been previously evaluated in databases of adequate size or controlled for some of these confounding factors.”

Based on this data, Jehle suggests several changes that might save lives.

“Extending the range of adjustable seats would be helpful, as well as encouraging moderately and morbidly obese individuals to buy larger vehicles with more space between the seat and the steering column.

“We also recommend that manufacturers design and test vehicle interiors with obese dummies, which currently are not available, in addition to testing with the 50 percentile (BMI 24.3) male dummy,” he adds. “It would improve safety for the one-third of the U.S. population that is obese. For underweight and normal weight individuals, placing airbags within the seat belt also might be protective.”

Jehle and colleagues set out to investigate the relationship between driver body size and risk of crash-related fatality by analyzing data in the national Fatality Analysis Reporting System database (FARS).

According to FARS, to be included in the database a crash must involve: “a vehicle traveling on a roadway customarily open to the public and must result in the death of an occupant of a vehicle or a non-motorist.”

From the 168,049 drivers in severe motor vehicle crashes entered in the database, 155,584 met the criteria for inclusion in the analysis.

Drivers were grouped based on body mass index (BMI)—weight in kilograms divided by height in meters squared—into underweight, normal, overweight, slightly obese, moderately obese, and morbidly obese categories.

Severe crashes between 2000 and 2005 that involved one or two vehicles (cars, pickups, SUVs or vans) were used in the analysis. Fatalities considered related to the crash that occurred within 30 days of the crash, such as those resulting from surgery, also were included.

In addition to the overall results, data analyzed by sex show that in the moderately and morbidly obese categories, both male and female drivers independently demonstrated a statistically significant increase in death when compared with normal-weight drivers.

“The rate of obesity is continuing to rise, so is it imperative that car designs are modified to protect the obese population, and that crash tests are done using a full range of dummy sizes,” Jehle states.

The research is funded in part by a grant from the Federal Highway Administration.

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chat2 Comments


  1. David

    Not enough detail here to say whether the study was flawed. Some past studies have suggested that slightly overweight people weather serious illness better than obese or normal-to-underweight people. It may not be that the injuries are worse, just that the survival rate is lower for obese individuals. That said, it seems obvious that autos should be tested and designed for all sizes of people. Few cars of any size can be adjusted to fit my height well, and I’m not outside the 95th percentile. A side impact in many cars could cause my head to strike the shoulder belt anchor hardware, which is rarely padded or even flat on the surface. Good adjustability of seats, steering wheels, pedals, etc. is often considered a luxury, hence only available in “luxury” cars. This practice needs to end. Offering motorized and/or memory functions in luxury models only is fine, but manual adjustability to fit 99.9% of individuals is a must for all cars. One reason people buy enormous SUVs and pickups is to get comfortably roomy interiors for the driver. Some would say that smaller cars mean tighter interiors, and currently that may be true, but this isn’t necessary. The first generation Scion xB has ample room for four, yet is compact, lightweight, was cheap to produce, and is significantly more fuel efficient than most vehicles.

  2. Due Bianchi

    I agree with David, manual adjustability is a must for all cars.

    The study is very interesting and I wiil use some material on / to create a great post.

    We need test dummies for overweight people but also for taller ones!

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