The National Highway Traffic Safety Administration (NHTSA) created federal vehicle regulations to help prevent and reduce crashes on the road. These regulations are known as Federal Motor Vehicle Safety Standards (FMVSS) and are designed to support laws passed by congress related to the design, performance, and safety features of vehicles sold in the US.
Regulation No. 126 is specific to the functionality of Electronic Stability Control (ESC). Each manufacturer may have a different name for ESC but the functionality between them all is the same. ESC is a vehicle system that controls and corrects vehicle yaw when exceeding stability limits, this is typically done by the system modulating your vehicle's brakes at all four wheels individually as needed. [From NTHSA, “An ESC system utilizes computers to control individual wheel brake torque and assists the driver in maintaining control of the vehicle by keeping the vehicle headed in the direction the driver is steering even when the vehicle nears or reaches the limits of road traction.”]
According to NHTSA, “ESC has been found to be highly effective in preventing single vehicle loss of control, run off the road crashes, of which a significant portion are rollover crashes.” Because of this, all passenger cars and trucks are required to have ESC systems and those systems must meet the performance requirements defined in the FMVSS No. 126.
The performance requirements consist of an oversteering test maneuver, lateral stability criteria, and responsiveness criteria. Each requirement is specifically defined and intended to insure your vehicle is safe in a wide variety of driving situations.
Testing is done on a closed course using robotics to control precise vehicle speed and steering maneuvers intended to simulate abrupt maneuvers that may happen out on the road such as an evasive lane-change. The vehicle is fitted with measurement equipment and sensors that record test events. The data is later analyzed to confirm if the test passed or failed.
Why does it matter to you?
When adding accessories and lifts to your vehicle, the driving characteristics and performance changes. It is critical to know that these changes will not negatively impact the performance of your ESC system. If you are ever in a situation where you need to make a sudden maneuver or sudden loss of traction occurs, it is crucial that your ESC system is functioning as intended in order to keep the vehicle under control. FMVSS No. 126 testing ensures that the AccuAir air suspension kits do not compromise the performance of your vehicle's ESC system.