I'm disabled and have a handicapped placard that I hang on my mirror. I'm sick and tired of people parking in handicapped spaces with no handicapped tags or placard on their mirror. Who do I call to have their vehicles towed?

Call local law enforcement

You can call the police and have them issue a ticket, but to have the vehicles towed you must contact the owner of the parking spaces. Walmart would have to call and have the car towed if it is in the handicap parking space in their lot for example, or the police could on a public street but they will probably only issue a ticket unfortunately.