WASHINGTON, D.C. -- August 15, 2003 -- A lax rule concerning tire pressure monitoring systems was arbitrary and violated safety requirements, according to a decision by the United States Court of Appeals for the Second Circuit. The rule did not meet the standards of the Transportation Recall Enhancement, Accountability, and Documentation Act (TREAD), which requires car manufacturers to install tire monitoring systems that indicate when a tire is "significantly under-inflated."
Issued by the National Highway Traffic Safety Administration (NHTSA), the rule gave automakers the option to install either of two types of tire monitors -- a model that shows when any of four tires are 25 percent below normal, or another model that shows when one tire is 30 percent under-inflated. The one-tire 30 percent model is the least reliable, because it does not produce a warning when the tire pressure falls in two, three, or four of the vehicle's tires at the same time and in roughly equal amounts. According to NHTSA records, this type of situation occurs in about half the cases of under-inflated tires. Also, this monitoring system does not function on bumpy or gravel roads.
In comparison, the four-tire, 25 percent system allows drivers to know when one or several tires are under-inflated. The NHTSA noted that 124 deaths and 8,722 injuries per year would be prevented by the four-tire 25 percent system, but only 79 deaths and 5,176 injuries would be prevented by the one-tire 30 percent system.
The Court of Appeals concluded that the four-tire 25 percent system can prevent more injuries, save more lives, and be more cost-effective than the other system, taking into account both safety and benefits. It ordered the National Highway Traffic Safety Administration (NHTSA) to rewrite the regulation to reflect this view.
The "...economic advantages of a standard cannot be considered without reference to the associated safety concerns," the Court said. It noted that the added cost to the manufacturer of a system that worked all of the time, rather than about half of the time, was less than $10 per car. "The adoption of the four-tire, 25 percent standard alone is the most cost effective means of preventing the crashes caused by significantly under-inflated tires," the Court said.
The lawsuit was brought by three nonprofit consumer groups -- New York Public Interest Research Group, the Center for Auto Safety, and Public Citizen. Public Citizen is a national advocacy group that represents consumers in Congress and in the courts. Its Auto Safety division works to improve highway safety by lobbying Congress to pass appropriate auto legislation, monitoring the Department of Transportation, and participating in lawsuits to force government action about auto safety issues.