What does a green traffic light signify for drivers?

A green traffic light signifies that drivers may proceed if it is safe to do so. This means that when approaching an intersection with a green light, drivers are given the permission to move forward, but they must first assess the situation to ensure that it is indeed safe. This includes checking for pedestrians, other vehicles, or any obstructions that might prevent a safe passage through the intersection.

The other options do not accurately represent the meaning of a green light. Stopping immediately would contradict the purpose of a green light, which is to indicate that driving is allowed. Preparing to turn left can also be misleading, as a green light does not specifically instruct drivers to turn; rather, it confirms that they can proceed straight or turn if permitted. Lastly, the idea that traffic must alternate does not apply; a green signal allows uninterrupted flow for traffic in that direction, rather than alternating it.