The Firestone and Ford tire controversy of the 1990s saw hundreds of people die in automobile crashes caused by the failure of Firestone tires installed on light trucks and SUVs made by Ford Motor Company.
Unusually high failure rates of P235/75R15 ATX, ATX II, and Wilderness AT tires installed on the first and second-generation Ford Explorer and similar vehicles caused crashes that killed 238 people and injured around 500 others in the United States alone; more died in other countries.
The revelations halved the market value of Firestone parent company Bridgestone, which fired or accepted the resignation of several executives and closed the Decatur, Illinois, factory where the tires were manufactured. Ford also fired or accepted the resignation of executives. Each company publicly blamed the other for the defects, a disagreement that ended the companies' nearly 100-year relationship.
Congressional inquiry into the scandal led to the enactment of the Transportation Recall Enhancement, Accountability and Documentation (TREAD) Act in October 2000.
Problem detection As early as 1996, personal injury lawyers were aware of accidents, injuries, and deaths caused when the tread separated from Firestone tires at high speeds. Lawyers and traffic safety researchers decided not to contact the National Highway Traffic Safety Administration (NHTSA) because they lacked confidence in the agency and feared that an investigation might conclude that there were no defects, thereby compromising existing personal injury lawsuits. All but 13 of the 271 known deaths from these tires took place after 1996.
In 1996, the Arizona state government told Firestone that the treads on its tires were separating in high temperatures. Firestone sent several engineers to inspect the tires and concluded that normal passenger tires were being used in heavy conditions, on dirt roads, off-road, and under heavy loads. Firestone replaced those tires with heavier-duty tires.
As early as 1997, internal Firestone documents showed a rise in injury claims for the ATX, ATX II, and Wilderness AT tires.
In July 1998, Samuel Boyden, a researcher for State Farm Insurance, received a call from a claims handler asking for information about tread separation in Firestone tires. Boyden subsequently found 21 crashes caused by tread separation and forwarded the information to NHTSA. In 1999, he found an additional 30 cases which he also forwarded to NHTSA.
In 1998, Ford began replacing Firestone tires in Venezuela, where 46 deaths had occurred, according to documents uncovered by Sean Kane, a researcher at Strategic Safety Consulting. Firestone was aware of tire defects in Venezuela as early as 1999.
A Ford dealer in Saudi Arabia noticed high failure rates of Firestone tires in Saudi Arabia, Qatar, and Kuwait starting in 1997 and in July 1999 began replacing Firestone tires on unsold Ford Explorers and to offer a 75% discount for replacement tires when customers came in for maintenance. Ford and Firestone began testing tires in late 1997 or 1998 and began a limited recall in the Middle East, Venezuela, Malaysia, and Thailand in 1999 and the spring of 2000 but did not notify NHTSA.
On February 7, 2000, KHOU-TV in Houston Texas ran a 9-minute story about high-speed Firestone tire failures on Ford Explorers that led to 30 deaths. KHOU was overwhelmed by phone calls from concerned citizens and started directing callers to NHTSA.
In 2000, Clarence Ditlow, executive director for the Center for Auto Safety, told the Senate Committee on Commerce, Science, and Transportation, "Emerging information shows that both Ford and Firestone had early knowledge of tread separation in Firestone Tires fitted to Ford Explorer vehicles but at no point informed NHTSA of their findings".
Firestone had more information about tire failures than Ford did because of warranty claims, but Firestone never acted on this information because it always blamed consumers for not maintaining their tires correctly or operating their vehicles in extreme environments, leading to these failures. When Ford and NHTSA looked into concerns about tire failures or rollovers, they consulted consumer complaints to NHTSA's toll-free hotline. The consumer complaints did not reflect the size of the problem because attorneys and their clients had almost completely stopped using the hotline to report tire failures or other complaints.
Investigation and possible causes On March 6, 2000, NHTSA began a preliminary inquiry into the high incidence of tire failures and accidents of Ford Explorers and other light trucks and SUVs fitted with Firestone Radial ATX, ATX II, and Wilderness tires. This became a formal investigation on May 2 (PE00020). On August 9, Firestone recalled all ATX and ATX II tires and all Wilderness AT tires manufactured in Decatur. On August 31, 2000, the Office of Defect Investigation (ODI) upgraded the investigation to an Engineering Analysis (EA00023) to determine whether Firestone's recall covered all the defective tires.
Ford and Firestone both sent root-cause analyses to NHTSA. Firestone argued that vehicle weight, tire design, low recommended inflation pressure, and lower tire adhesion for tires manufactured at the Decatur factory contributed to the tire failures. Ford argued that the tire design led to higher operating temperatures than similar tires manufactured by Goodyear; that Firestone tires' relatively small wedge, a strip of rubber between the first and second belts, made them weaker and more failure-prone than comparable Michelin tires; and that there were manufacturing problems at the Decatur factory.
Publicly, Firestone argued that Ford's recommended 26 psi inflation pressure should have been 30 psi. Firestone also argued that the Explorer was abnormally dangerous and prone to rollovers after a tire failure, leading to more injuries and deaths. Firestone CEO John Lampe said, "When a driver of a vehicle has something happen such as a tread separation, they should be able to pull over, not rollover."
Ford argued that the Explorer was no more dangerous than any other SUV and that the accident rate for Explorers with Goodyear tires was far lower than for Explorers with Firestone tires.
Some outside observers argued that both parties were to blame: Firestone's tires were prone to tread separation and failure, and the Explorer was especially prone to rolling over if a tire fails at speed compared to other vehicles.
Ford Explorer
Ford designed the first-generation Explorer by mounting an SUV cabin on a Ford Ranger undercarriage. This cut production costs because Ford could use existing facilities, parts, and robots. But the extra upper cabin weight on the pickup chassis created a vehicle with a higher center of gravity that was more likely to roll over in an accident. It was also more likely to sway during sharp turns because it used the same leaf spring suspension as the Ranger. The likelihood of a crash and likelihood of injuries and death from a crash were greater in an SUV experiencing a tread separation than on a pickup truck.
Ford came up with three options for correcting this problem: use shorter suspension springs to lower the vehicle half an inch in the front and one inch in the back, lower the tire pressure to give the Explorer a more car-like ride, or widen the wheelbase by two inches. After the Explorer rolled over in company pre-production tests, Ford decided to lower the suspension and remove air from the tires to 26 psi compared to 35 psi for the same tires on the Ranger. They did not widen the wheelbase, which would have required a substantial redesign. One consequence of lowering the tire pressure is increased tire temperatures which could lead to a tire failure. Firestone warrantied these tires at 26 psi for 11 years.
First offered for sale in March 1990, the first-generation Explorer had one of the lowest fuel-economy ratings of any SUV sold in the United States, due at least in part to Ford's recommended tire pressure. While designing the second-generation Explorer, Ford made two changes to reduce weight and improve fuel economy. First, Ford replaced the Twin I-Beam suspension with a lighter-weight short- and long-arm suspension, but did not lower the engine. This raised the Explorer's center of gravity, making it more prone to rolling in an accident or sharp turn. Second, Ford reduced the amount of material in the roof. When the new model went on sale in 1995, it was discovered that this lighter roof was so weak that it would collapse under the weight of an overturned Explorer if the windshield were smashed in, as often happened in rollover accidents.
After Ford Motor Company voluntarily recalled 13 million Firestone tires on May 21, 2001, Firestone requested that NHTSA investigate the handling and safety of Ford Explorers following a tread separation. Firestone argued that the Explorer is poorly designed and exhibits dangerous oversteer in the foreseeable event that a tire fails while driving. Firestone hired a consulting engineer to analyze the performance of the Ford Explorer and other SUVs during a tread separation, this report showed that the Explorer had a greater tendency to oversteer following a tread separation than other SUVs. NHTSA examined this report as well as real-world accident data and data provided by Ford concerning the design of the Explorer and denied Firestone's request. NHTSA stated that "[t]he many crashes following tread separations of tires on these vehicles that are documented in the Firestone claims database and that have been reported to ODI by consumers and others demonstrate that such a tire failure can lead to loss of control, particularly when it is a rear tire that fails and the vehicle is being driven at high speed. However, the fact that a vehicle exhibits linear range oversteer characteristics following a rear tire tread separation does not, in itself, indicate that the vehicle contains a safety-related defect. Moreover, the data available to ODI does not indicate that Explorers... are more likely to exhibit linear range oversteer characteristics following a rear tire tread separation than many of their peers."
The Explorer was redesigned for the 2002 model year. The tire pressure was raised to 30 psi, it was widened by 2.5 inches, the suspension was lowered, and independent rear suspension and electronic stability control were added.
Firestone tires The tires that were involved in these accidents were P235/75R15 ATX and ATX II tires and P235/75R15 and P255/70R16 Wilderness AT tires. These tires were installed as OEM equipment on the Ford Explorer, Mercury Mountaineer, Ford Bronco, Ford Ranger, Ford F-series pickup trucks, Mazda B-series pickup trucks, and Mazda Navajo between 1991 and 2000.
ATX tires were originally developed in the late 1980s for use on Ford light trucks and SUVs and were first installed on Ford trucks and SUVs in 1991. The ATX II was designed to improve the ATX's ride and the fuel economy of the Explorer. The Explorer had one of the lowest fuel economy ratings for any SUV under production at that time, due at least in part to Ford's decision to lower the tire pressure to 26 psi. Ford asked Firestone to reduce the weight of the ATX tires so that it could improve the fuel economy of the Explorer. Firestone created the ATX II by removing material from the tire which lowered the weight by 10%. Removing material from the ATX design also improved the profitability of the tire for Firestone.