ISTOCK
Every day, as you walk to school, ride your bicycle to cricket practice, or travel by car through the city’s busy streets, you’re likely to see traffic lights standing tall at nearly every major crossing. They flash their red, yellow, and green colours, silently commanding cars, buses, rickshaws, and even the occasional cow to stop, wait, or go. We follow their signals almost without thinking, but traffic lights are a clever invention that has made our roads much safer—and their story is far more fascinating than you might imagine.
Long before cities buzzed with the sound of horns and the rumble of engines, the idea of organising traffic was already a challenge. As far back as the 1860s in London, horse-drawn carriages, carts, and pedestrians crowded the streets. Policemen stood at busy junctions, waving their arms or blowing whistles to guide everyone safely across. It wasn’t easy—accidents and chaos were common. Then, in 1868, the world’s very first traffic light appeared outside the Houses of Parliament in London. This odd-looking device didn’t have coloured bulbs, but used gas lamps with red and green signals, operated by hand. At night, the red and green glowed through coloured glass, while during the day, semaphore arms signalled drivers and riders. Unfortunately, the gas lamp exploded after just a month, injuring the policeman operating it, and the idea was shelved for several decades.
It wasn’t until the early twentieth century, when motorcars began to zoom down the streets, that the need for organised traffic control became urgent. In 1914, an American city—Cleveland, Ohio—introduced the world’s first electric traffic light. It used just red and green lights, with a buzzer to alert drivers to changes. Soon after, the yellow (or amber) light was added, giving people a warning that the light was about to change—just enough time to stop safely or get ready to move.
The basic idea of traffic lights has stayed the same since then: red for stop, green for go, and yellow for slow down or get ready. But beneath this simple system is an amazing mix of science, technology, and psychology. Traffic lights are carefully placed and timed to keep vehicles and pedestrians moving smoothly, reduce accidents, and even help ambulances and fire engines reach emergencies faster. Engineers use computers to coordinate signals across entire cities, making sure traffic jams don’t spread like a domino effect.
India’s first traffic lights appeared in the bustling streets of Kolkata (then Calcutta) in the 1920s. Back then, there were far fewer cars on the road, but the streets were filled with trams, hand-pulled rickshaws, bullock carts, and hundreds of people on foot. As India’s cities grew, so did the need for better traffic management. Today, from Mumbai’s crowded intersections to the flyovers of Bengaluru and the broad avenues of Delhi, traffic lights are everywhere. Some are smart lights, using cameras and sensors to detect the number of vehicles and adjust their timings automatically. This “intelligent” technology helps reduce waiting times, lower pollution from idling engines, and even spot vehicles breaking the rules.
Have you ever wondered why red means stop and green means go? Red is the colour our eyes notice most easily, and it stands out even in poor weather or low light, making it ideal for warning drivers to halt. Green, on the other hand, is calming and easy to see, encouraging safe movement. Yellow is a colour that catches attention quickly but doesn’t carry the urgency of red, which is why it’s used for warnings. These colour choices are not just random—they’re the result of careful studies in how people react to signals.
Traffic lights do more than just control vehicles. Many crossings have “walk” and “don’t walk” signals to help pedestrians cross safely, and in some places, there are sounds or vibrations to assist visually impaired people. In Indian cities, you’ll often find countdown timers on the lights, letting everyone know exactly how long they’ll have to wait, which can be surprisingly satisfying—or, for some drivers, a race to beat the clock! There are even special lights for bicycles in some forward-thinking cities.
But even the best-designed traffic lights only work if everyone respects them. In India, where the roads are sometimes a wild mix of every kind of vehicle imaginable, following traffic signals can make a huge difference to safety. Running a red light isn’t just risky; it’s also against the law and can lead to hefty fines or worse. That’s why campaigns and school programmes around the country teach children and adults about the importance of road safety, making sure everyone understands what those three simple colours mean.
Over the years, traffic lights have become more than just machines. They’re often seen in art, cartoons, and films as symbols of order, choice, or even as clever metaphors for life’s decisions. In a way, they remind us that in a busy world, a little patience and respect for the rules can keep us all moving in the right direction.
The very first traffic signal, set up in London in 1868, used gas lamps. It only lasted about a month before it exploded, injuring the policeman who operated it.
Almost every country in the world uses the same three colours for traffic lights. No matter where you go, red means stop and green means go!
The first signals were made for horse-drawn carriages and carts, not automobiles.
The town of Berlin has a museum dedicated just to traffic lights, where you can see hundreds of different models from over the years.
In some parts of Japan, the green light looks much bluer because of the way the language and traditions describe colours.
At some super-busy junctions in big cities, you might be stuck at a red light for as long as 5–7 minutes!
Modern cities, including some in India, use smart traffic lights that can sense traffic jams and change their timings automatically.
Many traffic lights in big cities beep, vibrate, or talk to help blind and visually impaired people cross the street safely.
India is famous for adding countdown timers to traffic lights, letting drivers and pedestrians know exactly how long to wait or move.
In some cities, if you drive at a steady speed, you’ll get a string of green lights—this is called a “green wave” and helps traffic move faster!