Big Tires and Raised Trucks a Deadly Combination Study Finds, Safety Experts Warn of Highway Dangers; Photo Available 4/18/2004
From: Jason D. King of the American Association of Motor Vehicle Administrators, 703-908-8287 ARLINGTON, Va., April 19 -- The American Association of Motor Vehicle Administrators (AAMVA) released a study today warning that "aftermarket" oversize tires and lift kits have a potentially profound effect on the rollover propensity and braking performance of motor vehicles-a safety hazard that may lead to the unnecessary death and maiming of countless individuals every year. Prior studies have focused on the rollover propensity of vehicles straight off the manufacturer's assembly line. But AAMVA's study is the country's first to examine the effect lift kits and oversize tires have on used motor vehicles, particularly light trucks. "The crash involvement of raised vehicles has been difficult to quantify because there is no standard for law enforcement officers to use in recording these tragedies," said Linda R. Lewis, president and CEO, AAMVA. "But sadly, their tracks are permanently etched in the shattered lives of families nationwide." In addition to the demonstrated propensity to roll over and braking difficulty, light trucks raised several inches above stock can create mismatched bumper heights with traditional passenger cars. Experts note that when such cars crash with light trucks, fatalities are greater for the car occupants. And since light trucks have grown to represent 50 percent of new vehicles, the harm imposed on car occupants will grow as the percentage of light trucks increases. "Our study shows that raised vehicles can be harder to control," said Dave McAllister, crash investigation team leader, Virginia Commonwealth University and a member of the AAMVA working group that conducted the study. Unfortunately, the study didn't touch another factor commonly noted by accident reconstructionists: the difficulty in steering due to alterations. "When all factors are combined, raised vehicles that go out of control and then strike other vehicles outside their bumper's range simply compound the severity of such collisions," said McAllister. This study has only scratched the surface of the problem and AAMVA would like to see additional research to address a number of safety concerns. The association will explore developing model legislation with uniform inspection guidelines for inspecting vehicles outfitted with aftermarket body and suspension lift kits and/or oversize tires. AAMVA issued a broad base of recommendations to additional safety organizations designed to address these highway dangers, including; -- National Transportation Safety Board>conduct a study to understand the cause/effect relationship between oversize tires and the crash involvement of raised vehicles. -- Society of Automotive Engineers-identify safe practices and guidelines that would communicate what must be considered when installing replacement tires on light trucks. -- Specialty Equipment Market Association-distribute warning messages to raise end users' awareness of the effects oversize tires could have on the handling characteristics of light trucks. -- National Highway Traffic Safety Administration-examine collision data to establish a problem size assessment associated with light trucks whose ride heights have been excessively raised by aftermarket body and lift kits and/oversize tires. The AAMVA study used NHTSA's five-star rollover rating system and was conducted with tires ranging in size from 28 to 39.5 inches in diameter and with three-and four-inch body and suspension lifts. The study used a series of low-speed braking tests on a flat plate tester with a 4-wheel drive pickup truck. Two drivers performed a combined 147 brake tests using six different tire and suspension configurations. The AAMVA Vehicle Safety and Inspection Committee's Altered Height Working Group conducted this study at Hunter Engineering, St. Louis, Mo., in December 2000. Read the study at: http://www.aamva.org/Documents/vehStudyEffectOfOversizedTiresOnAlteredHeightVehicles.pdf Founded in 1933, AAMVA represents motor vehicle and law enforcement officials who are responsible for administering the laws governing motor vehicle operation, driver credentialing and highway safety enforcement. ------ Editor's note: High resolution, publication-ready photo(s) supporting this story available for free editorial use at: http://www.wirepix.com/newsphotos/ |