I set the cruise control at 70MPH then I reset the trip setting. after a quarter mile and throughout my ten mile trip and not altering my speed the trip meter claimed my avg speed to be 67MPH. I tried the same thing on my return trip hitting the resset after locking in the cruise at 75MPH and at the end of 10 miles the trip meter said my avg speed was 72MPH. Seems to be off by 3MPH. Ken.R