A new ‘white’ traffic light could let autonomous vehicles lead urban traffic, promising smoother, safer city commutes, writes Yashi Mittal, Head – Corporate Communications, Future Mobility Media.
Imagine this: You’re driving through a bustling city, your destination just minutes away. Ahead, you see the traffic light, glowing with colours you’ve known since you were a child – red for stop, yellow for caution, green for go. But now, right alongside these familiar shades, there’s a new colour—a soft, futuristic white.
This fourth colour, perhaps one day as common as the other three, is intended to support a world where autonomous vehicles (AVs) rule the roads. While fully autonomous cars are still emerging, advanced driver-assistance systems (ADAS) are already here, bridging the gap between human-driven vehicles and self-driving ones. ADAS features, like adaptive cruise control and automatic lane-keeping, are introducing drivers to cars that can make decisions, helping us transition to a future where the vehicle takes on a larger role. Researchers, engineers, and city planners, including those in India’s Smart Cities Mission, are working toward a future where these ADAS-enabled cars interact more seamlessly with urban infrastructure, making streets safer, more efficient, and much smarter. Here’s how the introduction of a “white light” might change not only our driving experience but the very fabric of our cities.
The Origins of the Fourth Colour: Why White?
Traffic lights have evolved as society’s relationship with transportation has changed. The red, yellow, and green signals we know today stem from the 19th-century railway system, a practical solution for controlling movement when cars were first taking over city streets. But with ADAS and autonomous technologies in our vehicles, roads are primed for an upgrade.
As autonomous vehicles become more sophisticated, they can “talk” to each other through advanced communication networks, making quick, coordinated decisions that improve traffic flow and reduce bottlenecks. The fourth colour—white—proposes a way for AVs to take advantage of this collective intelligence. When the white light appears, it signifies that AVs are in charge, guiding human drivers through an intersection simply by having them follow their lead. It’s a concept developed by researchers at North Carolina State University, designed to harmonise human and autonomous driving systems on roads that serve both.
The White Light’s Role: A Game of Follow the Leader
Under this new system, AVs would use the white light to effectively “take over” intersections. When enough autonomous cars are at an intersection, the white light switches on, indicating that human drivers should follow the flow of AVs. AVs, in turn, would communicate with each other to coordinate their movements safely and efficiently. No more stop-and-go waits at traffic lights or endless streams of vehicles clogging intersections; instead, we’d see a seamless flow.
Imagine driving behind an autonomous car as it guides you through a busy intersection, almost like being part of a choreographed dance. The concept of the white light is built on the trust that AVs, programmed with vast datasets and designed for rapid decision-making, can lead human drivers through intersections more effectively than a static red, yellow, or green light ever could.
For cities, this shift could result in more fluid and dynamic traffic management, with reduced congestion, fewer accidents, and lower emissions. In fact, in tests of AI-based systems for traffic lights, cities have seen up to 25% reductions in travel times and similar cuts in vehicle emissions due to smoother traffic flow. In India, cities like Delhi, Mumbai and Bengaluru, which are frequently plagued by traffic congestion, could greatly benefit from such systems.
Smart Traffic Systems: A New Layer of Urban Intelligence
But the white light is only one piece of a broader, AI-powered puzzle that cities are assembling. Many urban areas are investing in smart traffic systems to manage congestion and maximise road efficiency. These systems use sensors, cameras, and AI algorithms to assess and predict traffic flow, adjusting light timing in real time. In Pittsburgh, for instance, the AI-based Surtrac system adapts its timing based on live data, reducing delays and travel times for everyday drivers.
India, too, is exploring such options as part of its Smart Cities Mission. With dense traffic in urban areas like Mumbai and Chennai, and a diverse mix of vehicles on the roads, including buses, rickshaws, and two-wheelers, adapting AI-driven traffic systems to local needs could transform commuting. ADAS technologies, such as automatic braking and lane-keeping assist, are already improving the driving experience and safety on Indian roads. As this technology expands, smart traffic systems and eventually white-light intersections could transform daily commutes, particularly in sprawling metropolitan areas.
Reimagining City Streets: What Could the Future Look Like?
With AVs in charge and white lights directing the flow, the landscape of city streets could change dramatically. Imagine a street designed to prioritise AVs, with dedicated lanes that allow them to seamlessly navigate intersections without needing traffic lights at all. In a future dominated by AVs, traditional intersections may even become a relic, as cars equipped with V2V (vehicle-to-vehicle) communication could interact without stopping.
In India’s densely populated cities, this could mean not only less congestion but also safer and more organised traffic flow. The influence of AV-driven infrastructure would allow cities to redesign streets to prioritise pedestrians, cyclists, and public transportation. If AVs control traffic flow efficiently, urban spaces currently consumed by expansive roadways and traffic lights could be repurposed into pedestrian plazas, parks, or bike lanes, creating a more human-centred urban experience.
Challenges and Considerations: An Autonomous Road Isn’t Built in a Day
While the future of AV-guided traffic management and the white light sounds promising, implementing it will take significant work. For one, not every city has the infrastructure or resources to make this kind of change. Retrofitting intersections with white-light technology and AI sensors would require a substantial investment and likely face hurdles in public acceptance, especially in areas where people are less familiar with AV technology.
In India, the road infrastructure varies greatly from city to city, and some rural areas may not yet be suited for such advanced systems. Also, India’s roads often have a chaotic mix of vehicles, including heavy trucks, bicycles, and pedestrian traffic, requiring AV systems to adapt to these conditions. Developing AV-friendly infrastructure will require extensive testing and regional customization.
Furthermore, cybersecurity is a serious concern. With AVs communicating with traffic infrastructure in real time, a cyber attack could disrupt an entire city’s transportation network. As cities experiment with autonomous technology, they will need to build systems that can withstand security threats.
India’s Road Ahead: A Future with White Lights?
For India, adopting such technologies might seem like a distant reality, but the conversation is already beginning. India has been advancing its infrastructure goals under the Smart Cities Mission, which aims to make urban areas more sustainable and livable. ADAS is already making its way into Indian vehicles, offering a first taste of driver assistance and partial automation. As AVs begin to enter the global market, Indian policymakers will face decisions about whether to adopt white-light systems and autonomous-oriented infrastructure in densely populated cities.
Adopting a system like the white light would mark a monumental change, aligning India with a growing global movement toward smart cities. Autonomous vehicle tech could potentially alleviate some of the challenges facing India’s roadways, from pollution to congestion to road safety. In a nation where over 150,000 people die in road accidents each year, the idea of smarter traffic control is more than just a futuristic fantasy – it’s a necessity.
A Glimpse into Tomorrow: Will We Be Seeing White Lights Soon?
The concept of the white light represents a larger shift toward autonomous urban mobility, where technology takes a proactive role in our daily lives. With ADAS already present on our roads and AVs on the horizon, it’s clear that the red-yellow-green traffic light will eventually need an upgrade. Whether we end up seeing a fourth colour, smart adaptive signals, or even an entirely new method of managing traffic, the future of our roads is undeniably changing.
It’s a future where stop-and-go could be a thing of the past, replaced by a seamless flow led by autonomous intelligence and technology. And as cities around the world, including those in India, take their first steps toward this future, we’re witnessing the dawn of a new era in urban transportation – one where a simple white light might one day guide us all.