What colour are the obstruction lights that indicate hazards?

Obstruction lights that indicate hazards are red because red is the universally recognized color for warning signals, especially in aviation and transportation contexts. These lights are crucial for alerting pilots and vehicle operators to potential obstacles or hazards in their vicinity, particularly at night or in low-visibility conditions. The use of red helps ensure maximum visibility and is standard practice, as this color stands out against the natural backdrop of the sky, making it easier for operators to identify potential dangers during their operations.