An intersection that has four through phases and four protected left-turn phases is said to be what type of intersection?

An intersection with four through phases and four protected left-turn phases is classified as an eight-phase intersection.

In traffic signal terminology, each phase represents a specific period during which a set of movements is allowed or restricted. In this case, the four through phases accommodate the vehicles traveling straight through the intersection in different directions, while the four protected left-turn phases allow vehicles to turn left without conflict from oncoming traffic.

When you add together the number of through phases (four) and left-turn phases (four), you arrive at a total of eight distinct phases. This configuration is important for managing traffic flow efficiently and safely, ensuring that different movements can occur without interference. Understanding the number of phases at an intersection is crucial for traffic signal design, implementation, and optimization, as it influences how traffic is managed during different times of the day.