What is a pile or mound of material capable of restraining a vehicle called?

A pile or mound of material capable of restraining a vehicle is referred to as a berm. Berms are specifically designed to prevent vehicles from going beyond a certain point, providing safety and control in various environments, particularly in mining and construction sites. They can absorb the impact and provide a buffer zone, making them critical for managing vehicle movement and preventing accidents.

While other terms like "mound," "barrier," and "wall" might intuitively suggest a similar purpose, they do not encompass the specific function that a berm serves in a practical sense. A mound is more generic and does not imply the restraining capability; a barrier often suggests a more rigid structure; and a wall is typically vertical and may not specifically be used for restraining vehicles. The term "berm" is well established in safety protocols and design, making it the most appropriate answer for this question.