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Our Cars’ Weight Problem
How government is making our cars lighter, and more dangerous

A 2014 Smart ForTwo

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As we emerge from the long holiday season chasing new resolutions, many of us find ourselves focusing on watching our waistlines and taking off some extra pounds. As more Americans are diagnosed as obese, this renewed attention to health and weight can only be seen as a good thing. But America is also struggling with another weight problem — and what you don’t know about it just might kill you.

During the first term of the Obama administration, much was made of the bailout of the automotive industry. Common belief to the contrary, the U.S. government came to the rescue of all three of the major U.S. auto companies. We all know that GM and Chrysler received billions in federal loans and were forced to go through bankruptcy, but we sometimes fail to recall that Ford received a $5.9 billion low-interest loan from the Department of Energy and has paid back less than $200 million at the time of this writing.

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And here’s the part of the deal that got much less attention: the new mandate that all auto manufacturers achieve by 2025 a Corporate Average Fuel Economy (CAFE ) standard of 52 miles per gallon — twice the previous requirement of 26 miles per gallon.

At first blush, 52 mpg sounds like a laudable goal. What’s wrong with making more efficient cars? After all, they’ll be more affordable to drive, and simultaneously reduce the nation’s carbon emissions. Talk about a policy twofer!

The problem with the goal is simple: We can get only so far on the mileage front without affecting safety. Allow me, as someone who has spent a lifetime in and around the automotive industry, to explain why.

To get to where the government wants us to be, we start by employing all the engine technology possible to extract every last mile per gallon. This means using direct-injection combustion, variable valve timing, and sophisticated air management that includes more turbo-charging, as well as fine-tuning the engines with the use of sophisticated sensors and algorithms. The industry has done all of that, and today’s engines are impressively efficient.

We next turn to transmissions. These can help save fuel by allowing the engine to run at lower revolutions per minute (rpm). Think of being able to shift gears on a bicycle as you go up or down hills. This helps you get more from each pedal stroke. It is the same for vehicles. Today’s vehicles have progressed far from the original two-gear automatic transmissions; some offer as many as eight gears that automatically maintain engine rpm within a certain range. This has all been done, and the miles per gallon have improved accordingly.

However, all these efforts are not nearly enough to achieve the mandated 52 miles per gallon. So what else can be done? It’s what I call Jenny Craig engineering: reduce car weights, and reduce them massively.

It is a simple matter of physics: It takes less energy to propel a lighter object at a particular speed than a heavier object. You may wonder why so many vehicles suddenly stopped carrying a real spare tire years ago, or why there is so much plastic in vehicles today. Wonder no more: It was for weight reduction.

This is not a new trend; weight-reduction efforts have been ongoing since Jimmy Carter was in office. And they are not aimed just at larger vehicles. The Toyota Prius is slated to shed 500 pounds.

But less weight is a good thing, isn’t it? Well, not always. Why does professional boxing have weight categories that place athletes in competition with others the same size? Why is the NFL so concerned about the head injuries that seem to be happening with more and more frequency as players get bigger and faster?

Because size matters — and we all know it. Take this simple test. Imagine a head-on collision on a two-lane country road at a speed of 40 mph. One of the cars involved is a Cadillac Escalade and the other a Chevy Volt. Which would you want to be in? Which would you want your child in?

In a Cadillac minute, you would choose the Escalade. Because you don’t need to be an automotive engineer to know the big car will crush the small car. The driver in that little car will in all probability be severely injured, maybe killed. You, the driver in the Escalade, may walk away unharmed, or with only minor injuries.

Why? Once again, it’s physics. The force of something heavy and big crashing into something small and light leaves that something much, much smaller.

The same goes for that big heavy vehicle crashing into something stationary, like a wall or a tree. Or something pretty mobile — like a deer — crashing into the vehicle.



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