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WHY DO TRAFFIC LIGHTS USE RED, YELLOW, AND GREEN?

Every day, millions of people stop, slow down, and move ahead by following three simple colours—red, yellow, and green. These traffic lights keep roads safe and organised. But have you ever wondered why these particular colours were chosen? The answer takes us back to the days of the railway.

Long before cars filled the streets, trains relied on coloured signals to prevent accidents. On early British railways, red meant danger or stop, green meant caution, and white meant the track was clear. However, white soon created a serious problem. An ordinary lamp or light in the distance could easily be mistaken for the white “all clear” signal, putting trains at risk.

To solve this problem, railway engineers changed the system. Green became the colour that meant safe to go, while yellow (also called amber) was introduced as the colour for caution or warning. This new colour system proved much safer and easier to understand.

When traffic signals were introduced on roads, the railway colour language was adopted. But road traffic needed something extra. Drivers needed a warning before the light changed from go to stop. In 1920, a Detroit police officer named William Potts designed one of the first three-colour traffic signals, adding the yellow light between green and red. This gave drivers a few seconds to slow down safely instead of stopping suddenly.

Today, traffic lights around the world follow the same simple pattern: Red means stop, yellow means get ready or slow down, and green means go. These colours are easy to recognise, even from a distance, making roads safer for everyone.

AMAZING FACTS 

●The first traffic lights were inspired by railway signals, not cars.

●Red was chosen because it is highly visible and is often associated with danger.

●Yellow acts as a warning signal, giving drivers time to react.

●William Potts introduced the three-colour traffic signal in 1920.

●The same red-yellow-green colour system is used in most countries around the world.

WHAT WE CAN LEARN 

Traffic lights remind us that rules and patience save lives. Waiting a few seconds at a red light may seem inconvenient, but it helps prevent accidents and keeps traffic moving safely. These three colours are more than lights—they are a universal language of safety that has guided people for over a century.