What legal steps can resolve parking issues near my house?

Dear Sir/Madam, we have a hospital right in front of our residential premises, across the road. Many hospital visitors park their vehicles in front of our gate daily, causing inconvenience. They first park near the hospital, but when that space fills up, they park in front of our house. The hospital security doesn't seem to stop them. Despite multiple requests, the police intervened once but the problem resumed after a week. It also seems the hospital has influence, and the police don’t interfere. How can we resolve this? Is there any law that forbids hospitals from being near residential areas? Thank you in advance.