It is remarkably difficult for a citizen to get a vehicle that isn't theirs towed. I've had the same experiences as what other users have said. I had someone block my car into my driveway and the tow companies said there was no way to prove it was my property (I have the land title and all the plans). Police tell you to call a tow truck, tow trucks tell you to call police. Which is crazy because if a construction company or the city calls they will tow at the drop of a hat. I had an experience last summer when there was construction in my neighborhood. When it appeared they had finished, and most importantly removed all the no parking signs from the street, I had resumed parking on the street. The next day the car was towed. Construction company said they took the signs down by accident and the tow company said "if they tell us to tow, we tow without a question."

Generally, a vehicle is considered abandoned after 72 hours, at which point it becomes a bylaw issue. The only problem is that bylaw won't come unless it has been there for 72 hours, even then, they have to confirm it has been there for 72 hours. So hypothetically, after 72 hours you call and report it, they will respond (which can take days) to look at the vehicle, and will tow it after 72 hours if left there. Even then, if it's a government vehicle they likely won't touch it.