The key colors on stoplights have been around for a long, long time.

Red has meant stop and green has meant go since before there were stoplights; those were the colors used to signal trains in the pre-car days.

Yellow came along in the 1920s, as a way to improve safety so drivers didn’t have to slam on the brakes to avoid a newly changed red light.

Those have been the colors ever since, only there’s a body of research suggesting that we may need a fourth traffic light color going forward.

Popular Mechanics reported recently on the work out of North Carolina State University.

Like so many people in the transportation field these days, they’re looking at the effect that driverless cars and artificial intelligence could have on the roads.

Now there’s no reason that autonomous vehicles couldn’t just follow the same red, yellow and green lights than cars driven by humans use.

But one of the arguments for robot cars is that they would all know where each other was and they wouldn’t need to stop and start at set intervals like cars typically do now.

Instead, an AI system could route all the cars going on all the roads in the most efficient way possible.

There have been talks about building what are called smart intersections, as well as dedicated lanes for autonomous vehicles to help make this a reality.

But if that day ever comes, and we can’t say for sure it will, there are still going to be humans driving at least some of the cars along with the robots.

How can these different kinds of vehicles coexist without getting in each other’s way?

This is where the idea of the fourth stoplight color comes in.

The researchers say that when there are few driverless cars in an area, stoplights would continue to use red, yellow and green lights to direct traffic.

But when there are a lot of driverless cars around, and chances are high that those cars will be directing themselves around the nearby roads, the stoplights could change to the fourth color.

It would essentially tell drivers to do what the car in front of them does: go if the previous car went, stop if that car stops.

It would bring human drivers into those AI-powered traffic patterns and speed everyone along.

Though it would require that we upgrade pretty much all our stoplights.

And we’d have to agree on a color.

How about something with polka dots?

Today in 1980 the Popeye movie was released, starring Robin Williams and Shelly Duvall.

There’s probably no better place to mark the anniversary than Chester, Illinois.

It’s the hometown of Popeye’s creator, E.C. Segar.

They not only have statues of the spinach-loving sailor man and his friends all over town, they have a gift and memorabilia shop called Spinach Can Collectibles.

They even have a statue of Popeye’s dad, Poop Deck Pappy!

A Study Proves Stoplights Need a Fourth Color: White (Popular Mechanics)

The Popeye Capital of the World Is Hiding In Small Town Illinois And It’s As Weirdly Wonderful As You’d Expect (Only In Illinois)

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Photo by Andrew Malone via Flickr/Creative Commons