Abstract
This paper presents a comparison of some test methodologies. A g-analyst accelerometer, a VC.2000 accelerometer, and a bumper chalk gun/radar gun are compared for locked wheel friction values under different speed and road surface conditions. Data from the two on board systems are recorded simultaneously. Measurements are made for several stops at each of the speeds and two road surface conditions. Statistical analysis is performed on each test method for each set of test conditions to determine repeatability of that test method. These statistical analyses also indicate what real differences can be attributed to the experimental factors. (A)