Sitting in Running Car for Hours Every Day

My neighbor sits in her car with it running for hours, multiple times a day, every day. 3, 4, 5 sometimes 6-8 hours she sits in her car, in her driveway with the car running. She does it at all times of the day, the AM, PM, middle of the night, random times. Sometimes I see her feet on the dashboard, other times she has the sun shade up, (Because it's hot you know.) and at night I see the dash lights on so I know shes out there. I cant tell if shes sleeping, smoking weed, on the phone or what. She has a nice big 4 bedroom house, maybe 2-3 other people living there. I dont see any signs of domestic abuse, yelling or fighting or any obvious reason like screaming kids for her to be sitting in her car like that. This has been going on for over a year now. All the neighbors know about it but nobody wants to say anything because she's in her own driveway and nobody wants to create a problem with her. I never saw anything like this before and nobody knows what to do to get her to stop. Has anyone ever seen something like this before?