The point at which (delta symbol) occurs -- where the stake is driven -- is called the?

The point at which the delta symbol occurs, where the stake is driven, is known as the Point of Intersection (P.I.). In highway design and alignment, the Point of Intersection is critical as it represents the location where two tangents intersect, forming the vertex of a curve. This point is essential for defining the geometry of the roadway and for establishing the curvature that characters a linear roadway.

Identifying the P.I. enables engineers and designers to determine critical aspects of road design such as sight distance, radius of curvature, and expected vehicle dynamics at intersections. The P.I. is also used as a primary reference point in the layout of the vertical and horizontal alignment of a road.

In contrast, the other terms listed refer to different concepts in roadway design. The Point of Commencement typically signifies the starting point of a project or a phase of work, whereas the Point of Tangency is the point where a curve meets a tangent line, and the Point of Curvature marks the beginning of a curve from a straight line. Understanding these distinctions is vital for effective plan reading and roadway design.