These can be constructed from spare excavated material. They need to be steeply graded on the side facing the parking spaces, and should be graded into the landform on the other side unless they are intended to resemble hedgebanks or similar rural features. The steepness and height are essential to prevent four-wheel drive vehicles from climbing over them. In confined areas the face nearest the parking can be constructed of timber or stone revetment. Trapezoidal-section mounds should be avoided as these look too engineered. The mounds can be sown, planted or turfed with appropriate vegetation. If they are of a height similar to that of the bonnet/hood of the cars the mounds will help to screen them from views back to the car park. Trees can also be planted, which will hide the cars further and provide some shade and shelter. The gentler slope of the mound can also be used as informal seating.
Rocks
In areas where rocks are commonly found, either as individual elements or as outcropping, they can be used to make very suitable barriers. Large rocks can be dug into the ground so that they look fixed and are difficult to shift. They need to be big enough so that high-chassis vehicles cannot attempt to drive over them and so that any cars that accidentally bump into them do so with their bumper and not their sump! Rocks look better placed at irregular distances apart rather than in equally spaced rows. If some of the rocks have flatter tops they can make informal seats.
