I'm using Acti dome cameras. I have one camera aimed on my driveway. The street is masked out, but I get motion detect videos on all the cars passing by. Why?
If you email us a screenshot of your mask setup, along with a sample video clip (if it's small enough to send by email), we'll take a look to see what we can suggest.
As BrainM says, shadows or reflections could be the issue, but we'll know more if you can send the files.