My neighbors are having me stress over them parking beside the half of front yard. What can I do?

I live in between two homes on a deadend street. Ffront of my home is an broke down 18 wheeler parked in front neighbor's yard ( I already have trouble rev. back every morning to work ) the street is so narrow. I have 4 autos & park 2of them in my drive way & two of them on my yard so the street can have more space for other cars to pass by my house and my front neighbor's 18wheeler. Now my neighbors on my right side always park half of their rear truck or commercial bus/suv on my side of my yard making it more hard for my to get out of my home. You see they live in the corner of the street & have the advantage of having two car driveway + two sides to park on,but instead it is empty so their yard look clean & park their cars or trucks on half of my yard. I request them to move but nothin - Is this your question? Add additional information