6.0 ATC TEST PROCEDURE RECOMMENDED
Based on the preliminary testing that was conducted, the following test conditions, instrumentation and maneuvers are recommended for evaluating the performance of ATC at highway speeds:
Test Surface – Utilize a low friction test surface with a PFC of 0.25 or less. PFC can be determined by an ASTM traction trailer using the ASTM Procedure E-1337 as specified in FMVSS 105 and FMVSS 121. Actual measurement of PFC is not necessary but is useful to quantify the friction level of the surface being used. Ice, snow or wet epoxy coated surfaces are suitable. The surface must be slippery enough so that the vehicle drive axle(s) will break traction when the ATC is turned off and a rapid throttle application is made.
When comparing different ATC system configurations, care should be taken to design the test so that surface friction variation does not influence the results. For example, if testing on ice or snow, which tend to vary as a function of temperature and grooming, alternate the different ATC configurations from run to run or “back to back”. Test surface should be of sufficient size to allow the driver to safely recover from a loss of control event during the test maneuver.
Maneuver – Any or all of the following maneuvers are useful for evaluating the ATC engine control function.
Vehicle speed in the maneuvers must be above the speed at which ATC induced braking occurs or the traction control braking function must be disabled.
Instrumentation – Equip the vehicle with instrumentation to measure and record the following parameters versus time:
Test Vehicle Loading – Vehicle should be empty or lightly loaded