Which of the following is NOT one of the types of intersections?

The identification of "Diagonal intersection" as an option that is NOT typically classified among the types of intersections is grounded in the common terminology used in traffic and road design.

Intersections are usually categorized based on their geometric arrangement and how roads converge. Types such as Y intersections, where one road branches off another, crossroad intersections, which are more traditional four-way intersections, and six corner intersections, which refer specifically to intersections formed by three roads, including one that may be cut off or connecting oddly, are all established terms widely used in traffic literature.

On the other hand, while diagonal intersections may exist in a practical sense (like where two roads cross at an angle), they do not fit into the commonly recognized categories established in standard traffic manuals. Therefore, the label "diagonal intersection" does not reference a defined type in the same way the other terms do, making it the correct choice for the query regarding which is not typically recognized as a standard intersection type. This understanding is crucial for navigating transportation studies or practices effectively.