North Carolina may add a fourth color to traffic lights to have a big impact on driving experience
Published on Oct 17, 2025 at 2:30 AM (UTC-4)
by Molly Davidson
Last updated on Oct 17, 2025 at 7:50 AM (UTC-4)
Edited by
Mason Jones
What if the next set of traffic lights you stopped at had four colors instead of three?
In North Carolina, that’s an actual plan being explored by university engineers.
They say a new light could help drivers know when self-driving cars are taking control at intersections.
And if it works, it could make traffic faster, safer, and way less frustrating.
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Why a fourth color in our traffic lights could actually make sense
The idea comes from researchers at North Carolina State University.
Their proposal introduces what they call the ‘white phase’ – a new signal that appears when enough autonomous vehicles approach an intersection.
Those vehicles communicate wirelessly with the light and with each other to coordinate who goes where.
When the white light turns on, it tells human drivers one simple thing: follow the car in front of you.
If it moves, you move.
If it stops, you stop.
There’s no new set of rules to memorize, just a new way to flow with traffic.
If there aren’t enough self-driving cars nearby, the system switches back to the normal red, yellow, and green cycle.
But when it’s active, the benefits are massive.
Simulations show it could reduce travel time by up to 10 percent and lower fuel use.
It could also help cut down on the chaos that happens when drivers and bots mix.
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The road to making it real
Don’t expect to see white lights on every corner just yet.
For the system to really work, about 30 to 40 percent of cars on the road would need to be autonomous.
That’s a milestone we’re still some years away from.
Even so, North Carolina could become one of the first testing grounds as companies like Tesla, Ford, and Waymo keep pushing toward full autonomy.
Waymo says the idea is promising but warns against rushing to install AV-only infrastructure too soon.
Still, this might be the biggest update to traffic lights in a century.
If the white light takes off, it won’t just change intersections.
It’ll change how humans and machines move through the world together.
With roles at TEXT Journal, Bowen Street Press, Onya Magazine, and Swine Magazine on her CV, Molly joined Supercar Blondie in June 2025 as a Junior Content Writer. Having experience across copyediting, proofreading, reference checking, and production, she brings accuracy, clarity, and audience focus to her stories spanning automotive, tech, and lifestyle news.
