NICET - Highway Construction Inspection Practice Exam

The point where a circular curve begins is referred to as the point of curve. This is the location on the roadway where the alignment of the road transitions from a straight line into a curve. It's a crucial reference point in highway design, as it marks the onset of the curvature, allowing engineers and inspectors to properly identify the start of the circular path that vehicles will follow.

Understanding this concept is essential because the point of curve plays a significant role in ensuring safe design speeds along the curve, managing superelevation, and determining sight distances for drivers. The identification of this point is important for proper construction practices and ensuring compliance with design standards.

The other points mentioned serve different purposes in the context of road design and geometry. The point of tangency is where the curve meets the straight section of road, serving to delineate the end of the curve. The point of intersection refers to where two roadways cross each other, which is not relevant to the beginning of a curve. The point of extension is related to the measurement of the curve's progression and alignment beyond the arc itself. Hence, the point of curve is specifically the correct designation for the beginning of the circular curve.