Bridge Lights and Signals 101

Bridge Lights and Signals 101

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Bridges that help vehicles cross over bodies of water or navigable waterways rely on lights for signaling and safety. Regulated by the US Coast Guard, the obstruction lamps guide boats crossing under the bridge, as well as drivers crossing over the bridge. This article takes a closer look at types of bridge lights used for operations in marine environments.

Obstruction Lights (Under the Bridge)

Bridge lights designed to help boats pass under bridges consist of red and green lamps. Operating only at night (after sunset), the units are always on and do not flash. It is important to consider that not all types of bridges require this type of setup. Such lighting systems are mostly applicable to bridges with overhead limitations.

Red lamps are utilized to mark dangerous obstructions and certain limitations in range and height around the bridge. Such elements may include columns, pillars and etc.

On the other hand, green lamps are applicable to assisting boats pass under the bridge. Typically setup in a range configuration (two fixtures lined up), vessel operators carefully watch the light during the approach. This allows the boat to maintain a straight course towards the center of the bridge or its opening.

Signaling Lights (Over the Bridge)

Some bridges require signaling lights over the structures, which advises drivers when it is safe to pass. Like obstruction lights, not all bridges have signaling lights. For drawbridges, signaling safety lamps are critical to operation, as the road must be closed when the bridge is raised or turned.

Signaling lights for bridges incorporate a basic traffic light configuration, consisting of red, yellow and green lamps.

Some bridges may include a flashing yellow light with a cautionary sign at the approach. This advises drivers to slow down and prepare for braking maneuvers. The yellow lamp may flash, signaling that the bridge is in operation.