If you are the type of car enthusiast who has nightmares about hot new European cars that never make it to the United States, then you need to ask yourself a question: Do you wear your seat belt?
As unusual as it might sound, that is a major reason why automakers can have trouble selling the same car in Detroit and in Düsseldorf, and in Stuttgart and Seattle.
You see, about 85 percent of American drivers use seat belts. While the United States has closed the long-standing gap with Europe, it lags behind countries such as Germany, Sweden and the Netherlands, where more than 90 percent of drivers buckle up.
We love our freedoms, after all. And to deal with that, the National Highway Traffic Safety Administration requires that car companies crash-test their vehicles one more time, to see what would happen to a crash-test dummy that isn't wearing a seat belt.
Europe has no such requirement. So naturally, European companies dislike having to follow the American way. It means spending more time and money to certify a vehicle, even if a vehicle needs no engineering changes to meet American standards.
For instance, when Fiat bought a stake in ailing Chrysler in 2009 and decided to sell its Fiat 500 in the United States, it took 18 months to get the car re-engineered for the American market. One of the main changes? Bigger airbags to help the car pass the unbelted occupant test.
Some vehicles, especially low-volume ones, never make it through the gantlet of tests. The cost is just too high.
And that is why killing the unbelted test is one of the European auto industry's top goals during the latest round of free-trade talks between the United States and the European Union.
The watchword is "regulatory harmonization."
Backers of the trade deal say that regulations in the United States and Europe are pretty much equivalent, and that having the same rules on both continents would lower the cost of developing cars.
That would lead to savings to consumers and would make American and European automakers more competitive with Asian rivals.
But the regulators who oversee the two testing procedures insist there are reasons why Europe and the United States have their own rules.
A few weeks ago, NHTSA Administrator David Strickland met with Automotive News at his office in Washington. He had just attended a meeting about the trade talks. The topic was fresh on his mind.
"I think everybody is focused on the opportunity that we have, from an economic standpoint," Strickland said. He said that with so much at stake, regulators know they cannot blindly insist that their own regulations are the best.
But in the case of the unbelted tests, Strickland said, regulators are "fairly confident" that unless more Americans start wearing seat belts, "more people may end up getting injured or getting killed from the elimination of that test right now."
His point: Knocking down differences between the United States and Europe may not be worth it, when all the data are considered. Even if regulatory harmonization helps car companies engineer their cars more quickly and cheaply, lives are at stake.
So the lesson for the car-buying public is this: Wear your seat belt. The next time you walk into an auto show or a car dealership, you might be glad you did.