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SUMMARY: This document responds to a petition for reconsideration of our 2003 final rule establishing a braking-in-a-curve performance requirement for single unit trucks and buses. The braking-in-a-curve requirement has applied to air-braked truck tractors since 1997 and we determined that the requirement should also apply to single-unit trucks and buses. The requirement ensures that a vehicle's antilock brake system (ABS) maintains adequate stability and control during a hard stop on a curved, slippery road surface. A petition for reconsideration was received from the National Truck Equipment Association (NTEA), which seeks to exclude vehicles built in two or more stages and altered vehicles from the braking-in-a-curve requirement if such vehicles are manufactured or altered by a final stage manufacturer or alterer that builds no more than 250 affected vehicles per year. The agency is denying the petitioner's request for the reasons discussed in this document.