Shock and Vibration Environment Recorder (SAVER™) (Lansmont Corp., Monterey, CA) model SAVER™ 9X30 with Saver Xware programming software was used in this study. This type of data recorder uses an internal triaxial accelerometer to measure vibration levels in the vertical, lateral, and longitudinal directions. The data recorder was rigidly mounted to the vehicle’s chassis just above the rear wheel. Figure 2 illustrates the location of the data recorder.