Study Says Future Traffic Lights Could Have 4 Colours

A study conducted by North Carolina State University shows that an additional white traffic light signal, for self-driving autonomous vehicles (AVs), would greatly improve travel times at busy intersections.

How would it work?

The proposed four-light system would work the same way as today’s traffic lights except for an additional white light that shows when enough AVs are detected on the road.

The white light signals to human drivers that the self-driving cars at the intersection have taken control of the traffic via wireless communication. During the “white phase”, human drivers will be required to follow the vehicle in front which will efficiently guide them through the congestion.

The four-signal set-up requires AVs to communicate with each other and the traffic light infrastructure. The colour of the fourth light doesn’t matter, it’s only there to let human drivers know what to do.

What are the benefits?

The computer simulations conducted in the study showed that as AVs increased, delays decreased. As little as 10% of the vehicles at the intersection needed to be autonomous for delays to drop by 3%. When just 30% of the cars were autonomous, delays fell by 10.7%.

Artificial intelligence is much more efficient at leading traffic than the stop-start cycles of today’s lights. By working collaboratively, AVs can calculate the most efficient sequence for traffic to travel, saving motorists time and money.

When will it happen?

While four-light traffic signals remain a distant reality, researchers are optimistic about their feasibility once more self-driving cars reach production.

In the UK, a new law passed by the government could see self-driving cars hit UK roads as soon as 2026. The legislation, which lays out the legal framework for AVs, is thought to be the first major step towards an autonomous future.

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