I always thought that they were completely random, but today I found that they occur at exactly 800 metres (≈ 0.5 miles) when driving at 63 km/h (speed limit +3), under these conditions: AP1 @ 2017.28 c528869 Country road No lead car I logged 0,8 km no less than twelve (12) times in a row. I did it by resetting the trip meter every time the nagging occured. Unfortunately I didn't get a chance to log the intervals at other speeds... Please contribute to this thread with more data! BTW @verygreen have you by any chance seen any SW-code on this subject?