What causes geometric delay at an intersection?

Geometric delay at an intersection primarily results from the physical design and geometry of the intersection itself, which necessitates that vehicles reduce their speed to safely navigate through it. This encompasses factors such as the turning radius, lane widths, and the overall configuration of the intersection. As vehicles approach, they often must decelerate to make turns or to comply with traffic control devices, which contributes to the delay in movement.

The need to navigate curves, maintain safe speeds, and potentially yield to other traffic or pedestrians means that vehicles spend additional time within an intersection compared to traveling on a straight and unobstructed path. Consequently, this slowing down impacts the overall traffic flow and adds to the delays experienced, particularly during peak hours when traffic volume is higher.

In contrast, late signal changes affect the timing of lights rather than the physical navigation through an intersection. Traffic congestion from accidents is largely related to external factors and does not specifically pertain to the geometric characteristics of an intersection. Similarly, unexpected pedestrian crossings introduce delays due to traffic control but do not stem from the intersection's geometric design.