Traffic lights: A boon or bane for city mobility?

New Delhi
Red, green and amber traffic lights now flash at every corner, easing, or as some motorists argue, obstructing their daily commute. Love them or loathe them — they have become an unavoidable part of urban life, with their numbers steadily rising as cities grapple with increasing traffic on roads.
For instance, in Bengaluru, traffic police data reveals a 33% increase in traffic signals over the past five years. The city currently has around 405 signals, up from 300 in 2019, with plans to add 100 more in the coming months.
Delhi has over 990 traffic signals, Mumbai has 660, and Chennai has 312, and their numbers are steadily increasing.
“We are not installing signals randomly. There are 1,003 traffic junctions in the city, and the decision to install a signal at a particular intersection is made after thorough studies by traffic and transport engineers to ensure optimal traffic flow,” says MN Anucheth, joint commissioner of police (traffic), Bengaluru. “We plan to install signals at 100 more intersections in the coming months. The number of private vehicles is increasing at a massive speed. Currently, the city has over 1.20 crore (12 million) vehicles; five years ago, it had only 56 lakh (5.6 million).”
Bengaluru, with approximately 2.31 million private cars, has now surpassed Delhi as the city with the highest number of private vehicles in India. According to the Delhi Statistical Handbook, as of March 31, 2023, Delhi had 7.95 million vehicles, including 2.07 million private cars.
In 2022, Bengaluru was the second most congested city globally, according to a report by TomTom, a Dutch location technology specialist. The report noted that it took an average of 29 minutes and 9 seconds to travel just 10 kilometres in the city centre.
A history of traffic signals
The world’s first traffic light was installed at Parliament Square in London on December 10, 1868. It consisted of two movable signs attached to pivoting arms controlled by a lever, with a gas-lit semaphore on top for visibility. However, it was short-lived — less than two months later, the traffic light exploded, killing the police officer operating it.
The world had to wait 46 years until electricity became widespread for the first dual-coloured traffic light to be installed in Cleveland, Ohio, on August 5, 1914. In 1920, Detroit and New York added the yellow light between red and green. Most of Europe’s largest cities — Paris, London, Rome and Prague — got electric traffic lights in the 1920s.
In India, the first traffic lights were installed in Kolkata ( then Calcutta) in 1928 at the intersection of Esplanade and Dalhousie Square, marking the beginning of organised traffic control in the country. By the 1950s, other major cities, such as Delhi and Chennai (then Madras), had installed traffic lights, followed by Bengaluru (then Bangalore) in 1963.
In 2021, the Bengaluru City Police commemorated the city’s first traffic signal, installed at NR Junction in 1963, with a special event where the signal and pole were decorated with flowers.
More traffic lights: better cities?
While many cities such as Bengaluru continue to add more traffic signals, some cities in India are moving in the opposite direction, opting for signal-free roads to increase speed. For example, last year, Kota declared itself a signal-free city. Meanwhile, Chandigarh, which had previously removed roundabouts to install signals for smoother traffic flow, is now reconsidering this approach.
So, are traffic lights the most effective way to manage traffic? It is about progressive measures, say experts.
“Cities should gradually move from uncontrolled intersections to roundabouts, then to traffic signals, followed by grade separators (flyovers), and finally, to interchanges,” says Sewa Ram, a professor of transport planning at the School of Planning and Architecture (SPA), Delhi.
“This transition should be made in order, based on traffic volume. For instance, if there are more than 3,000 passenger car units (PCUs) or 6,000 two-wheelers passing per hour, a roundabout is generally more effective. It can be expanded to accommodate up to 5,000 cars per hour, but beyond that capacity, a traffic signal becomes necessary,” he says.
“However, signals have their limitations. As traffic flow increases, the waiting time at signals also rises. Signals are not very efficient at intersections with more than four arms. To make signals work better at such intersections, factors such as approach width, entry mouth and other design elements must be carefully considered. If an intersection has more than 10,000 cars per hour approaching from different roads, a grade separator is required,” adds Ram.
Proponents of signals argue that they not just help regulate traffic flow, but also reduce accidents, and promote democratic streets.
Amit Bhatt, managing director ( India) at the International Council on Clean Transportation (ICCT), emphasises the need for a balanced approach that uses infrastructure wisely and enforces safe speed limits. “We need to understand that signal-free roads can be a nightmare for pedestrians and cyclists, as they compromise safety. Ultimately, it depends on the kind of road speed a city aspires to maintain. Globally, in cities, the trend is moving towards a speed limit of 20 miles per hour (about 32 km/h), whereas in many Indian cities, vehicles often drive at speeds of 80km/h,” says Bhatt
Akash Hingorani, principal architect and urban designer at Oasis Designs, an architecture firm based in Delhi, advocates for a higher number of traffic signals in cities. “Ideally, there should be a signal every 500 metres in city centres. Streets are meant to move people, not just cars. Look at New York, especially Manhattan, which has a network of closely spaced, signalised intersections that effectively regulate the movement of vehicles, cyclists, and pedestrians in a highly congested environment,” he says.
He adds, “For pedestrians, frequent signals provide safe crossing opportunities, reducing the risk of accidents. It has been proved that footbridges and underpasses are not quite effective in this respect as they are barely used for different reasons.”
Some cities are recognising the benefits of roundabouts for reducing accidents at certain intersections. For instance, the Chandigarh administration, which had been replacing roundabouts with traffic signals before halting this practice in 2018, recently constructed a new roundabout designed with cyclists and persons with disabilities (PwDs) in mind. This decision followed a 2018 study showing that traffic signals were more prone to accidents than roundabouts, prompting a shift in policy.
Hingorani lauds the move, saying, “Cities should also build roundabouts to calm traffic at intersections prone to rash driving and accidents.”
Signalling inclusivity
In recent years, many cities have gained attention for their innovative experiments with traffic signals, using these everyday road fixtures to make bold statements.
In 2020, Mumbai became the first Indian city to introduce female figures on its traffic lights, a move welcomed by women’s rights campaigners, who saw it as a step towards greater inclusivity.
Similarly, on August 5 this year, the Greater Chennai Traffic Police installed heart-shaped red traffic lights at some busy junctions to mark World Traffic Lights Day, commemorating the first traffic lights installed in Cleveland, Ohio, on August 5, 1914.
“The idea was to raise awareness about the importance of following traffic rules. The heart-shaped traffic lights were meant to remind motorists that their loved ones are waiting at home and to encourage them to follow all road safety measures,” a Greater Chennai Traffic Police (GCTP) officer said.
Globally, many other cities are making similar efforts. Transport for London (TfL), for example, introduced traffic lights featuring a green wheelchair symbol instead of the traditional walking person, ahead of International Day of Persons with Disabilities ( PwD) on December 3 last year. This change, implemented at five prominent pedestrian crossings across London, aims to provide more inclusive representation for wheelchair users and improve accessibility.
Signals, psychology and economy
Well-synchronised signals, says Bhatt can help boost the local economy by attracting shoppers, while a signal-free road may see fewer customers.
Hingorani agrees. “ Also, lowering the speed in a city means the whole city becomes more enjoyable and safer.”
Dr Deepak Raheja, a clinical psychologist, says traffic signals play an important role in managing driver stress. “By providing predictable intervals of movement, well-timed signals ensure smooth flow of traffic that prevents long, unpredictable jams. This helps alleviate driver frustration, reduce aggressive driving behaviour, and ultimately, enhances overall road safety,” he says.
Bengaluru traffic JCP Anucheth argues public transport must be made cheaper, faster and more efficient to reduce the reliance on private vehicles and congestion in cities.
Bengaluru, which has only 72 kilometres of Metro network, compared to Delhi’s almost 400km, requires a boost to its public transport, he says. “ Building more roads is not the solution; cities with robust public transport will be better equipped to tackle traffic issues and improve overall urban mobility.”