📄 The History of Traffic Lights — How Red, Amber & Green Keep Drivers Safe

Traffic Lights: How Three Colours Learned to Control Millions of Drivers

Traffic lights are so familiar that most drivers follow them automatically, often without thinking. Yet these simple coloured signals are one of the most powerful safety systems ever introduced to our roads.

Old traffic junction with manual police control

Life Before Traffic Lights

Before traffic lights existed, junctions were chaotic. Police officers or railway-style signals controlled traffic by hand, and accidents were common as roads became busier. Cities urgently needed a clearer, more reliable system to prevent chaos.

The first traffic signal in London, 1868

The First Traffic Signals

The first traffic signal appeared in London in 1868 — and it ran on gas. Unfortunately, it exploded, injuring the officer operating it. While it wasn’t an immediate success, it highlighted the urgent need for traffic control as cities grew busier.

The Birth of the Three-Colour System

In the early 20th century, electric traffic lights were introduced in the United States. Red meant stop, green meant go, and amber was later added to warn drivers that a change was coming. This simple colour system quickly spread worldwide, and drivers adapted rapidly.

Why These Colours?

The colours weren’t chosen at random. Red had long signified danger, green was associated with safety, and amber was bright enough to be noticed without being alarming. This logic continues today in roads and railways around the world.

Modern Smart Traffic Lights

Today’s traffic lights are smarter than ever. Sensors detect vehicles, pedestrian buttons manage crossing times, and some systems adapt in real time to traffic flow — all designed to reduce congestion and improve safety on the roads.

Simple Signals, Massive Impact

Traffic lights do more than control traffic — they prevent collisions, protect pedestrians, and keep cities moving. Without them, modern driving would be chaotic. Their history is a reminder that even small innovations can have a huge impact.