Final answer:
At a solid green light, drivers should proceed with caution and yield to vehicles already in the intersection to avoid accidents and ensure traffic safety.
Step-by-step explanation:
During a solid green light, you are generally expected to proceed with caution through the intersection. However, if there are vehicles already in the intersection, such as those finishing a left turn or caught in the intersection due to congestion, you are required to yield to them. A solid green light indicates that it is your turn to go, but it does not override the basic traffic rule that requires drivers to avoid interfering with the progress of other vehicles already lawfully using the intersection. Therefore, even though you have a green light, you must yield to vehicles that are already in the intersection to ensure traffic safety and prevent accidents.