What color are the stop bar lights at holding positions?

The stop bar lights at holding positions are red. This color serves a critical function in aviation safety by providing a clear and unambiguous signal to pilots and vehicle operators, indicating that they must come to a complete stop before proceeding. Red is universally recognized as a signal to halt, which helps prevent accidents on the airside by ensuring that aircraft and vehicles do not enter taxiways or runways when they are not cleared to do so. This color coding adheres to established aviation standards and protocols, enhancing safety measures at airports.