The Science Behind Yellow Sodium Lights on Roads

To illuminate roads in big cities at night, high-capacity bright lights are required. Mostly, yellow-glowing sodium lights are used for this purpose. There is science behind choosing yellow light instead of the attractive white light of mercury, tubelights, and halogen bulbs.
When white light passes through certain mediums, it splits into seven colors, creating colorful halos. This process is seen more often when there are raindrops in the atmosphere, causing a hindrance to traffic. The yellow light of a sodium lamp spreads uniformly and does not undergo refraction easily. Sodium lights are also more efficient - a 1-watt sodium light gives off more brightness than a 1-watt tubelight. The same logic applies to keeping car and vehicle headlights yellow.