Everybody has waited impatiently at traffic signals. They’re most often the cause of congestion in urban areas, mainly because people don’t play by the rules of traffic lights. In urban India especially, lack of road discipline leads to massive traffic snarls almost every day.
In some places, traffic signals are replaced with roundabouts, while in some cases, the reverse happens. According to a Guardian report, the United Kingdom (UK) is replacing roundabouts with signals, while those in the United States (US) are doing the opposite. Roundabouts help dispersal but only in low-traffic situations. When it comes to high volumes of traffic, the only replacement for a signal is a signal-free interchange or a flyover but only if designed properly.
Closer home, Bengaluru replaced a few traffic signals with yield signs, which however did not work as expected. A yield sign is one which informs motorists that they have to give way to a vehicle on the side of the signboard. In India, it is typically used when traffic is coming in from the right-hand side.
Is automation the key?
Perhaps. However, the level of automation also matters.
Researcher Abdul Reza Fayazi of Clemson University in South Carolina designed a system that could eliminate traffic signals entirely, but there was a catch. The system was designed to work with fully autonomous vehicles.
How does this system work? It’s simple. Since each vehicle is autonomous, or self-driven, the location of the vehicle is tracked via the Global Positioning System (GPS). This data is transmitted to a server which records all the data available from different vehicles. The system then derives an optimal speed that each vehicle would have to drive at to prevent vehicles from lining up at signals. By regulating speed, a vehicle can effectively avoid a signal. Since there is limited idling at signals, it is estimated that fuel consumption goes down by 19 per cent.
Fayazi posted a video explaining the system along with a small demo.
However, there was one small issue that Fayazi faced while experimenting with his new system – the lack of an autonomous vehicle. So, instead, he drove a regular car with the system telling him what speed to maintain.
This brings us to the present. While fully autonomous vehicles are still years away, and every vehicle being autonomous decades away, why not introduce some automation into the existing scheme of things?
Various projects have been implemented in the past to minimise stoppage time at traffic signals. In 2012, the Coimbatore City Municipal Corporation and Coimbatore Traffic Police together set up a ‘Green Corridor’ on Avinashi Road. The concept was simple – every vehicle maintains a minimum speed of 45km/hr. Signals are then synchronised in such a way that once someone crosses the first signal, so long as the minimum speed is maintained they wouldn’t have to stop at any other signal en route. Sounds fine on paper. But the scheme didn’t work out well. Power shortages and lack of backup options for signals threw the entire system off gear, preventing its expansion to other arterial roads in the city.
However, an important lesson has been learned here. If a system has been set up with synchronous signals with the first one equipped with sensors that change depending on traffic, a completely ‘signal-free’ corridor can be possible.
How about getting rid of the signals?
We’ve come this far. We know that signals can be timed, that they can adjust themselves based on traffic. So why not use this data differently?
Eliminate traffic signals at a junction and replace them with sensors. Then, set up digital signboards along the corridor, again equipped with sensors. Each sensor detects vehicles, and their speeds, and relays it to a server. This server tabulates all the data and relays an optimal speed for the driver, which is then displayed on these digital signboards. As long as the user maintains this speed, there will be no need to stop.
It may be expensive to set up digital display units everywhere, but a lot of people have a smartphone. The added benefit of a smartphone is that it can relay its position via GPS to the server at any time. This is the principle with which Ola and Uber operate. Instead of sensors picking up vehicle data, relaying it to a server and then displaying a speed, the phone transmits its location to the server, which in turn tells the driver what speed to maintain. If the driver does not adhere to this speed, the phone can then remind them, something which may not be possible in the other scenario.
However, both systems, like the existing system of traffic signals, fail when humans don’t follow it. This is known to be a major problem in big Indian cities, where people continue to drive across a junction even after the light turns red. To solve this, traffic discipline needs to be enforced. The traffic police must make it a point to observe and issue spot fines to those violating rules. Only if this is achieved will people stick to a certain speed.
Eliminating traffic signals by controlling the speed of approaching vehicles isn’t a tough task, but if it is done well, it could make a city several levels smarter. A smart city is only as smart as its residents want it to be.
Srikanth’s interests include public transit, urban management and transportation infrastructure.
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