I have a similar issue. I am on a corner. People like to turn the corner short and drive across my yard. I added a ~400 lb rock to the corner of my lot. About every 4-6 weeks I have to put it back where it belongs and pick up car parts. It has a lot of different colors of paint that has been rubbed onto it. I am now shopping for a 1500 to 2000 lb rock to put there so that cars can not move it so easy.
I have also used the pieces of re-bar with a spherical radius on the end set down to ground level. With a round end I can claim that I was trying to make them as safe as possible. Round will easily penetrate a tire, even the tire of a semi size truck.
The other thing that has worked real good is to plant some rocks that are about a foot in diameter. Unless it is a lifted, or modded truck this is more that the available ground clearance of most vehicles. I have a line of those spaced about 8 feet, I then planted Tiger Lillie's (also known as Day Lillie) along that line. The plants look nice, require no trimming as the mower can pass under the leaves, can handle getting run over once in a while, and completely hide the rocks. When someone tries to go thru them they end up getting hung up to where they often need help getting away. The rocks also do wonderful things to the bottom of the vehicle. I did have one person that called the cops and insisted that a ticket be written since there was significant damage to her car. After much insisting by her, the cop did finally write a ticket,,,,,,,,,,,for trespassing. Then she was really unhappy.