I. INTRODUCTION AND BACKGROUND
A. Bridgestone/Firestone Recall
In 1990, Bridgestone/Firestone (BF) began production of a specially-designed, 15-inch ATX tire to be used as original equipment on the Ford Explorer that was being introduced in the 1991 model year. This tire was used as original equipment on several other Ford models and was sold directly to consumers as a replacement tire. A redesigned version of the tire was introduced in both 1995 and 1996 when the tire was renamed with two names, the ATX II and the Wilderness AT.
In 1996, BF started to receive a large number of claims relating to the 15-inch version of these tires. Most claims involved allegations of tread separations in which the tread and one of the steel belts separated from the other steel belt and carcass. Then in mid-1997, Ford dealers in the Middle East began to report similar problems with the 16-inch Wilderness AT tires. Testing conducted by Ford and BF led to limited recall actions in the Middle East, Venezuela, Malaysia, and Thailand in late 1999. In March 2000, the National Highway Traffic Safety Administration (NHTSA) opened an initial inquiry after 25 complaints were received between 1999 and 2000.
In May 2000, NHTSA opened a defect investigation into approximately 47 million ATX, ATX II, and Wilderness AT tires manufactured by BF, and issued a letter to Ford and BF requesting information about the high incident of tire failure on Ford Explorers. During July, Ford obtained and analyzed the tire failure data. The data revealed that the 15 inch ATX, ATX II and Wilderness AT tires had a very high failure rate, where the tread peels off. Many of these tires were made at the Decatur, Illinois plant. When the tires failed, many of the vehicles rolled over resulting in serious and fatal injuries to the occupants.
In August 9, 2000, BF announced the voluntary recall of all Firestone Radial ATX and Radial ATX II tires in the size P235/75R15 produced in North America, and Wilderness AT tires in the size P235/75R15 produced at the Decatur, Illinois plant. According to BF there were approximately 14.4 million of these tires produced, and they estimated the recall would involve 6.5 million tires still in use. That estimate included 3.8 million Radial ATX and ATX II tires and 2.7 million Wilderness AT tires. It was believed that these tires accounted for the majority of the tread separations being reported. The recalled tires were supplied as original equipment on many SUVs, including:
1991-2000 Ford Explorers
1996-2000 Mercury Mountaineers
1991- 2000 Ford Rangers
1991-1994 Ford F-Series
1991-1994 Ford Broncos
2001 Ford Explorer Sport Tracs
1994-2000 Mazda B Series
1991-1994 Mazda Navajos
After a four month analysis, BF announced that a certain group of their tires, primarily on Ford Explorers, may have been more likely to experience tread separations. This increase in tread separations in extreme cases was caused by several factors acting in combination. These factors were the tread design of the P235/75R15 tires, certain manufacturing factors related to the Decatur, Illinois manufacturing plant, and external factors on Explorers, including low tire inflation pressure and overloading of the vehicle.
Ford had recommended a tire inflation pressure for their SUVs of 26 psi, which was less than the 30 psi inflation pressure recommended by BF. Both of these recommended inflation pressures are less than the "maximum inflation pressure" marked on the sidewall of the tire. Most vehicle manufacturers recommend tire inflation pressures that are less than the maximum pressure marked on the tire sidewall. Many manufacturers recommend pressures less than the tire manufacturer's recommended pressure. These slightly lower tire pressures can create greater traction which improves the vehicle's handling and stability. However, the greater traction is due to the increased friction between the tire and the road, which generates more heat in the tire, that can contribute to the failure of marginal performing tires. After the recall on September 24, 2000, Ford announced that it was informing its SUV owners to inflate their Firestone tires to 30 psi, which is the BF recommended pressure.
Congressional investigators found evidence that BF knew their tires had serious defects in 1996, when 8 of 18 tires pulled from the production lines failed high speed tests. Seven of these failed tires were made in the Decatur plant. The Congressional inquiry eventually led to the Transportation Recall Enhancement, Accountability and Documentation (TREAD) Act of November 2000. The Act provided stronger penalties, longer recall periods, enhanced enforcement authority and increased funding to enable the agency to move vigorously with its defects investigations, to protect the public from the danger of defective products. The Act also specifically directed the agency to upgrade the tire safety standards, improve tire labeling information, and mandated that low tire pressure warning systems become required equipment on vehicles within two years.
B. TREAD Act requirements for upgrading tire standards
The TREAD Act, Section. 10, Endurance and resistance standards for tires states, "The Secretary of Transportation shall conduct rulemaking to revise and update the tire standards published at 49 CFR 571.109 and 49 CFR 571 119. The Secretary shall complete the rulemaking under this section no later than June 1, 2002."
C. Current Tire Standards - FMVSS No. 109/110/117/119/120/129
The present tire standards: FMVSS No. 109; New pneumatic tires, FMVSS No. 110; Tire selection and rims; FMVSS No. 119; New pneumatic tires for vehicles other than passenger cars; and FMVSS No. 120; Tire selection and rims for vehicles other than passenger cars, were established over thirty years ago before radial tires were introduced into the market, and have remained virtually unchanged.
FMVSS No. 109, New Pneumatic Tires - Passenger Cars, 49 CFR 571.109, specifies the requirements for all tires manufactured for use on passenger cars manufactured after 1948. This standard, which was issued in 1967 under the National Traffic and Motor Vehicle Safety Act (Safety Act), specifies dimensions for tires used on passenger cars and requires that the tires meet specified strength, resistance to bead unseating, endurance, and high speed requirements, and be labeled with certain safety information. FMVSS No. 109 applies to passenger car (P-metric) tires produced for use on passenger cars, light trucks, and multipurpose passenger vehicles (MPVs), including sport utility vehicles (SUVs). The standard was adopted in January 1968 from the Society of Automotive Engineers (SAE) recommended practice J918c, Passenger Car Tire Performance Requirements and Test Procedures, which was first issued by the SAE in June 1965.
The current FMVSS No. 109 includes four performance requirements for tires: a strength test that evaluates resistance to puncture in the tread area, a resistance to bead unseating test that evaluates how well the tire bead is seated on the rim, an endurance test that evaluates resistance to heat buildup when the tire is run at 85%, 90%, and 100% of its rated load nonstop for a total of 34 hours in an under-inflated condition, and a high speed test that evaluates resistance to heat buildup when the tire is run at 88% of its maximum load at speeds of 75 miles per hour (mph), 80 mph, and 85 mph for 30 minutes at each speed. The FMVSS No. 109 performance requirements are discussed further in Chapter II.
For the purposes of testing tires to determine their compliance with these standards, several variable factors such as the tire's inflation pressure, the load on the tire, and the rim on the tire on which a tire is mounted, must be specified. The agency specifies a limited number of permissible inflation pressures (or wheel sizes, in the case of the bead unseating test) to facilitate testing. The standard requires that each passenger car must have a maximum permissible inflation pressure labeled on its sidewall (S4.3). Section 4.2.1(b) lists the permissible maximum pressures: 32, 36, 40, or 60 pounds per square inch (psi) or 240, 280, 290, 300, 340, 350, or 390 kiloPascals (kPa). A manufacturer's selection of a maximum pressure has the effect of determining the pressures at which its tire is tested. For each permissible maximum pressure, Table II of the standard specifies pressures at which the standard's tests must be conducted. The intent of this provision is to limit the number of possible maximum inflation pressures and thereby reduce the likelihood of having tires of the same size on the same vehicle with one maximum load value but with different maximum permissible inflation pressures.
Closely related to FMVSS No. 109 is FMVSS No. 110, Tire Selection and Rims - Passenger Cars, 49 CFR 571.110, which requires that each passenger car be equipped with tires that comply with FMVSS No. 109, that tires on all cars be capable of carrying the load of that vehicle, that the rims on the car be appropriate for use with the tires, and that certain information about the car and its tires appear on a placard in the passenger car. FMVSS No. 110 also establishes rim dimension requirements and further specifies that in the event of a sudden loss of inflation pressure at a speed of 60 miles per hour, rims must retain a deflated tire until the vehicle can be stopped with a controlled braking application. FMVSS No. 110 initially became effective in April 1968.
FMVSS No. 117, Retreaded pneumatic tires, 49 CFR 571.117, establishes performance, labeling, and certification requirements for retreaded pneumatic passenger car tires. Among other things, the standard requires retreaded passenger car tires to comply with the tubeless tire resistance to bead unseating and the tire strength requirements of FMVSS No. 109. FMVSS No. 117 also specifies requirements for the casings to be used for retreading, and certification and labeling requirements. FMVSS No. 117 initially became effective in January 1972.
FMVSS No. 119, New pneumatic tires for vehicles other than passenger cars, 49 CFR 571.119, specifies performance and labeling requirements for new pneumatic tires designed for highway use on multipurpose passenger vehicles, trucks, buses, trailers and motorcycles manufactured after 1948. Under this standard, each tire has to meet requirements that are qualitatively similar to those in FMVSS No. 109 for passenger car tires. The high speed performance test in this standard only applies to motorcycle tires and to non-speed-restricted tires of 14.5-inch nominal rim diameter or less marked load range A, B, C, or D. But, FMVSS No. 119 does not contain a resistance to bead unseating test. The FMVSS No. 119 performance requirements are discussed further in Chapter II.
A tire under this standard is generally required to meet the performance requirements when mounted on any rim listed as suitable for its size designation, at the time of the tire's manufacture, as specified by the tire and rim associations publications that are listed in the standard. Further, the tire is required to meet the dimensional requirements when mounted on any such rim of the width listed in the load-inflation tables of this standard. In addition to the permanent marking for any non-matching listed rims, each tire manufacturer is required to attach to the tire, for the information of distributors, dealers and users, a label listing the designations of rims appropriate for use with the tire. FMVSS No. 119 initially became effective in September 1974.
FMVSS No. 120, Tire Selection and rims for motor vehicles other than passenger cars, 49 CFR 571.120, requires that vehicles other than passenger cars equipped with pneumatic tires be equipped with rims that are listed by the tire manufacturer as suitable for use with those tires, and that rims be labeled with certain information and establishes that these vehicles shall be equipped with tires and rims that are adequate to support the fully-loaded vehicle.
FMVSS No. 120 was promulgated January 19, 1976 (41 FR 3478, January 26, 1976), and became effective in August 1976. The primary effect of Standard No. 120 is fulfillment of ' 202 of the Act by specification of the minimum load-carrying characteristics of tires not already subject to the passenger car tire and rim selection requirements of FMVSS No. 110. The rim selection requirements were limited to the use of a rim designated as suitable by the tire manufacturer for use with its product. The use of "DOT" labeled rims was required on and after September 1, 1979.
Tire selection under FMVSS No. 120 consists of two elements. With one exception, each vehicle must be equipped with tires that comply with FMVSS No. 119 and the combined load ratings of those tires on each axle of the vehicle must at least equal the gross axle weight rating (GAWR) for that axle. If the certification label lists more than one GAWR-tire combination for the axle, the sum of the tires' maximum load ratings must meet or exceed the GAWR that corresponds to the tires' size designation. If more than one combination is listed, but the size designation of the actual tires on the vehicle is not among those listed, then the sum of the load ratings must meet or exceed the lowest GAWR that does appear.
FMVSS No. 120 also contains a requirement related to the use of passenger car tires on vehicles other than passenger cars. The requirement states that when a passenger car tire is installed on a multipurpose passenger vehicle, truck, bus, or trailer, the tire's load rating must be reduced by a factor of 1.10, i.e., by dividing by 1.10 before determining whether the tires on an axle are adequate for the GAWR. This 10 percent de-rating of P-metric tires provides a greater load reserve when these tires are installed on vehicles other than passenger cars. The reduction in the load rating is intended to provide a safety margin for the generally harsher treatment, such as heavier loading and possible off-road use, that passenger car tires receive when installed on a MPV, truck, bus or trailer instead of on a passenger car.
FMVSS No. 129, New non-pneumatic tires for passenger cars, includes definitions relevant to non-pneumatic tires and specifies performance requirements, testing procedures, and labeling requirements for these tires. To regulate performance, the standard contains performance requirements and tests related to physical dimensions, lateral strength, strength (in vertical loading), tire endurance, and high speed performance. The performance requirements and tests in FMVSS No. 129 were patterned after those in FMVSS No. 109.
The FMVSS No. 129 labeling requirements are similar to those set forth in section S4.3 of FMVSS No. 109 for size, designation, load, rating, rim size and type designation, manufacturer or brand name, certification, and tire identification number. The standard also includes temporary use and maximum speed labeling requirements and allows methods of permanent marking other than "molding" in anticipation of the difficulty of molding required information on non-pneumatic designs. FMVSS No. 129 became effective in August 1990.
D. Changes in U.S. Light Vehicle Market
Sales of light trucks (sport utility vehicles, vans and minivans, and pickup trucks) have increased steadily over the past 20 years and now account for almost half of the U.S. light vehicle market. While the number of passenger cars sold was 9.0 million units in 2000, the consumer preference for light truck vehicles continued to grow, reaching approximately 8.4 million units, just short of parity with passenger car sales. (Automotive News , 2001 Market Data Book).
Given the strong consumer demand for light trucks and that approximately 80% of these light trucks use passenger car (P-metric) tires, the net impact on original equipment passenger car tire shipments in 1999 reflects a record total of 61 million units, or a 6.8% growth over 1998's figure of 57.1 million units. Continued growth in the sales and production of light truck vehicles also drove the number of original equipment light truck (LT) tires to a record high of approximately 8.4 million units or a 25.2% increase over 1998's figures. (RMA 2000 Yearbook)
Given the increasing consumer preference for light truck use for passenger purposes, the agency believes that the tire standards being considered for passenger car tires should be extended to LT tires (up to load range E) used on light trucks. Load range E tires are typically used on SUVs and light trucks with a gross vehicle weight rating (GVWR) up to 10,000 pounds
E. Tire Harmonization
Work in UN/ECE's World Forum for Harmonization of Vehicle Regulations
On January 1999, the Rubber Manufacturers Association (RMA), along with five other petitioners, submitted a petition proposing that the agency begin rulemaking procedures to amend FMVSS No. 109 by adopting a new standard, Global Tire Standard 2000 for New Pneumatic Car Tires (GTS-2000). According to the petitioners, the proposed GTS-2000 harmonized the best safety practices of various national standards. NHTSA granted this petition in June 1999. And in July 1999, NHTSA participated in the first of a series of working group meetings on global harmonization for passenger car tires with the Economic Commission for Europe (ECE), Working Party of Experts on Brakes and Running Gear (GRRF). The ECE/GRRF is responsible for developing safety regulations on brakes, tires, wheels, and other chassis components of motor vehicles.
The GTS-2000 proposal was used as a basis for initial discussions on harmonization and substitutes a single high-speed test for the four performance tests in FMVSS No. 109 for most radial tires. (1) More specifically, GTS-2000 was intended to replace the current FMVSS No. 109 high speed test with the high-speed test required by ECE-R30 (the European tire regulation for tires used on light passenger vehicles), including temporary spares, and limits the application of the other three tests currently required by FMVSS No. 109, namely the strength test, the bead unseating test, and the endurance test. RMA believes that these three tests have relevance to bias and bias-belted tires but little, if any, relevance to radial tires, with the single exception of the endurance test for low speed (160km/h/99 mph, or less) radial tires.