On april 25, 2019 i was driving on a city street and the audi pre sense unexpectedly activated quite violently for about 2 seconds and then turned off. while it did not stop the car completely it did reduce my speed significantly. at the time i was the only car on the road; that is, there were no other cars within sight of mine. there was no damage that i can see to the car but i trust you can understand that this could have been a much worse situation if someone had been following closely behind me. i also trust you understand that this unexpected braking is unacceptable. the audi service advisor told me he has seen this phenomenon before but audi has no explanation or solution to the problem.