- The Washington Times - Friday, May 9, 2003

It all started with a dead pedal.

On an early test-drive of the upcoming 2004 Cadillac XLR sports car, engineers asked what I thought of their baby.

All in all, I thought it hit its mark, I told them. But among my nit-picky complaints was the fact that the dead pedal, a feature I especially like in sports cars to rest my left foot on, was positioned too far forward for my short legs to reach.

Chief engineer Dave Leone had heard no such complaint from the other writers. “Have you ever been measured?” he asked.

I might have been insulted, except I knew precisely what he was talking about. General Motors engineers often talk about vehicles designed to accommodate a 5th percentile female to a 95th percentile male.

I figured it was similar to the way a pediatrician weighs and measures children and then charts the numbers on a graph to show where the child ranks in size against the majority of the population.

Turns out it was far more complicated than that.

Days later, Mr. Leone had me lined up with a crew of GM’s ergonomics specialists who had worked on the XLR. They were to measure me and explain how they design vehicles that accommodate the millions of variations of body shapes.

I ditched my shoes, had my height measured, and then I climbed into the seat of a contraption that looks like a medieval torture chamber. Called an “anthropometer,” the device was built by GM’s design staff in the 1960s.

Over the years, it has measured thousands of people, from celebrities such as race car driver Rick Mears and the queen of Spain to ordinary citizens at various marketing clinics.

GM Chairman Rick Wagoner and Vice Chairman Bob Lutz, both very tall men, are wanted for measurement but have evaded the chamber thus far.

And then there’s Les and Toni, both GM employees. Les stands 6 feet, 4 inches and is a 99th percentile male. Toni, hired when GM specifically advertised for a small woman, is a 5th percentile female. Les and Toni participate in various product reviews and test-drives during the development of new vehicles to ensure vehicles fit a wide span of sizes.

The measurements of all these people are stored in a vast database used to help engineers and designers create a vehicle package that accommodates the widest array of sizes.

After checking my standing height, one of GM’s ergonomics engineers measured the top and bottom half of my legs as well as my floor-to-knee height when I was seated.

As I stared at a light, he took a reading on my sight line.

He measured upper and lower parts of my arms, my torso length, from my buttock to the top of my head and — yikes — seated hip width.

“Your shoe size?” he asked. I later learned pedals are designed to fit men’s 13 EEE work boots. Finally, he weighed me — how had those 8 pounds I’d lost returned without my knowing, I wondered.

He read each measurement to someone inputting numbers into the computer.

Then the computer went to work calculating the percentage each body part fell into. It spit out a printout with the silhouette of my body, each measurement shown, and next to it the percentile.

I was not the 5th percentile I’d expected.

I’m a freak!My measurements were all over the map. My lowest ranking was my 8th percentile legs; my highest was my 76th percentile torso. Wide variation is not uncommon, Mr. Leone assured me.

Specific to the XLR, the engineers said they had designed it to accommodate larger males more than smaller females, because men likely will be the target market.

“If we’d moved the dead pedal rearward, people like Les wouldn’t have room for their knees,” Mr. Leone said.

In fact, he added, a vehicle always could be designed to fit a small person, so large sizes take precedence. Then it became clear why I couldn’t reach the dead pedal.

I came away from the experience with a new appreciation for the challenging job car designers and engineers face in building vehicles that fit the majority of consumers.

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