We have this issue all the time. We live across from a dog park. People just do not care. Our only option is to call bylaw every damn time. I have poked my head out the door and informed a few of them that as we have a person with a chronic illness living here, we may need to leave at any time to go to the hospital. Should they decide they'd still like to leave their car blocking my driveway, they should also realize that I will simply throw my car in reverse and move them out of my way forcefully, and figure out the mess once we're done at the hospital. Most move their vehicles. We have 3 #######s who simply don't give a #### and shrug and walk away. I'm now collecting picture evidence per the bylaw cops and I have to write up a statement and include the pictures and they will begin ticketing them if they attend and the car has already moved. Here, bylaw can only ticket them. If they are fully blocking our egress and ingress, then the RCMP will be called. If bylaw calls a tow truck or I call a tow truck, I pay for them to remove the vehicle. If the RCMP calls, then the vehicle owner pays for the tow. Or so we've been informed anyway.
ETA: we also have issues with people using our yard to turn around to park on the other side of the street. As in, driving up across the corners of our yard, through the bottom of the driveway and across the corner of the yard on the other side of the driveway. We're going to go talk to some farmers and ask if we can have a couple big rocks from their rockpiles, which we're going to stick on each corner of the yard for the winter.
Maybe that will work because we've tried flags and they just drive over them regardless.