Critics contend that geographic recalls make a false assumption: that vehicles are only owned and operated in specific areas where they might or might not be exposed to specific weather and road conditions.
Cars are driven to other states and the market for used cars is now national, they argue. In decades past, a trade-in likely found a new owner nearby. Today, a large share of trade-ins pass through the vehicle auction system that might see a car shipped across country if high demand somewhere else would yield a higher resale price.
Industry data show that a typical vehicle is traded in every three to four years. With the average vehicle now lasting at least 11 years, it could have been operated in three very different environments before being scrapped.
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NHTSA "is not dealing with the issues," said Joan Claybrook, a former NHTSA Administrator and a frequent critic of the way the agency and the auto industry handle safety-related issues.
Claybrook questioned how regulators could confidently limit the scope of the Takata recalls to Florida if NHTSA admits it doesn't fully understand why the airbags are failing in the first place.
The data clearly support focusing on areas like Southern Florida, however, said Toyota spokesman John Hanson.
"We started gathering the air bags and Takata began testing them," he said. "The compiled data began to show there was a much higher percentage of air bag failure in the southern Gulf Coast than in other parts of the country. We know there's a higher level of humidity in that area."
Hanson said Toyota previously announced a nationwide recall for vehicles using Takata airbags, but has issued an updated advisory focusing on the Gulf region. Other makers, however, are focusing solely on high-humidity areas.
Blumenthal and Markey want to have geographic recalls banned as part of an updated federal highway safety bill. In light of the massive General Motors ignition switch recall, the Connecticut lawmaker said there is strong bipartisan support that gives a new safety measure "a good shot" at passage in Congress.
But there are opponents who want to retain the regional practice, in part, because it can make it easier to achieve a compromise between NHTSA and automakers who might otherwise balk at a broader, more expensive recall campaign, industry experts say.
One NHTSA insider, who asked not to be named citing agency policy, said that a manufacturer has to "contact us … and justify" limiting a recall by region.