What does a blue light indicate in the East River tunnels?

In the context of the East River tunnels, a blue light serves as an indication for Communication Safety Stations. These stations are critical for enhancing safety and emergency communication capabilities within the tunnel environment. The blue light alerts personnel and train operators to the presence of specific communication equipment that can be used in emergencies, facilitating faster response times and better coordination during incidents.

Understanding the presence of these stations is essential for safety protocols, especially in a complex operating environment such as a tunnel, where communication might be limited. Recognizing this indicator allows crew members to ensure they can effectively communicate during critical situations, enhancing overall operational safety.

Other options relate to various safety functions but do not represent the specific purpose of a blue light in this context. Communication Safety Stations are vital in creating a safe operational environment, particularly in emergencies where clear and rapid communication is essential.