SUMMARY: This notice of proposed rulemaking would establish a new Federal Motor Vehicle Safety Standard (FMVSS) No. 226@ to reduce the partial and complete ejection of vehicle occupants through side windows in crashes@ particularly rollover crashes. The standard would apply to the side windows next to the first three rows of seats in motor vehicles with a gross vehicle weight rating (GVWR) of 4@536 kilogram (kg) or less (10@000 pounds (lb) or less). To assess compliance@ the agency is proposing a test in which an impactor would be propelled from inside a test vehicle toward the windows. The ejection mitigation safety system would be required to prevent the impactor from moving more than a specified distance beyond the plane of a window. To ensure that the systems cover the entire opening of each window for the duration of a rollover@ each side window would be impacted at up to four locations around its perimeter at two time intervals following deployment.