The origin of the traffic light countdown timers

We all know that, at traffic signals, red indicates stop, yellow means slow down, and green is for go. But, did you know that drivers face a “dilemma zone” at the signals? This is when they must choose whether to brake or proceed at top speed when the green light is about to change to yellow or, even worse, when the yellow light is going to turn red.

Invisible at first

This is where traffic-light countdown timers help. They are digital displays that show the number of seconds remaining before a signal changes colour. Though digital timers became part of Indian roads only recently, automatic timers that control traffic lights were introduced in 1922 and replaced a large number of traffic officers who would otherwise manually operate the signals. In New York City alone, the number of traffic officers decreased from 6,000 to 500. However, the timer was not visible to users.

In the 1990s, the invisible became visible but was directed at pedestrians. Countdown timers were introduced at pedestrian crossings at the height of the human eye to help people know whether they had enough time to cross the road before the signal changed colour. This particularly benefited seniors, people with mobility challenges, and anyone needing to judge crossing time more accurately.

It’s not clear when traffic managers realised the usefulness of visible countdown timers for the main vehicular signal system. Ideally, when road users know exactly how much time remains before a signal changes, they are less likely to make abrupt or unsafe manoeuvres and are likely to decelerate smoothly and stop safely. When drivers know the exact moment of change, red-light violations decrease and overall decision-making becomes more conscious and measured. Timers also reduce time lost at “start-up”, meaning vehicles begin moving more promptly when the light turns green resulting in better traffic flow and reduced unnecessary delays.

Time to cross the street
| Photo Credit:
Getty Images/iStockPhoto

In some conditions, like on our roads, certain drivers tend to accelerate aggressively as the timer nears zero, increasing risk. However, given increasing congestion in urban areas, countdown timers offer promising advantages not only for vehicles but also importantly for pedestrians. Public awareness is also important so that road users do not misuse or misinterpret timers as is maintaining the technology properly.

Over a decade ago, while biking in Pune, I remember being pleasantly surprised to find a timer at a signal. Just knowing how much time I had before the signal changed was a great relief. While countdown timers help commuters make informed decisions, for me, they made sure that I was not in dilemma mode any more.