Motion alert triggered by sound?

Since some time, my floodlight camera creates a false alert almost every time a car drives by.I checked the detection zone, and it's far enough from the road, so the alert is not triggered by motion. I also set the sensitivity to the lowest level.I have the feeling the alert is triggered by sound - every time a 'loud' vehicle passes. Is that possible? If so, how can I disable or adjust the sound trigger?If not, what else could cause the false alerts for vehicles passing on the road?