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Why Most Highway Signs Aren't All Caps Anymore

Gregory Castillo

A drive down I-95 is full of dozens, probably hundreds, of tiny design decisions that are ultimately about driver attention. From the lettering on a road sign to the shape of a road, engineers are constantly trying to find a sweet spot between getting a driver’s attention and distracting them.

As part of our End of the Road series we wanted to ask an expert about the thinking behind some of the things drivers see everyday on I-95 but aren’t supposed to pay much attention to.

Gene Hawkins is a professor at Texas A&M University and a leading authority on why interstates look the way they do. He sat down with WLRN-Miami Herald News to talk about highway lettering, the boring way I-95 ends and why a straight highway is a dangerous highway.

A lot of the things that we drive by on the interstate are just words and numbers: speed limits and warnings and exit names. And there’s actually a lot of thought behind how those words look, even the mix of capital letters and lowercase letters.

That’s exactly right. When a word is spelled with all capital letters, it’s just a big rectangle from a long distance off. The signing book that existed -- and still does today -- is called the Manual on Uniform Traffic Control Devices, the MUTCD. And the signs that were in the 1948 MUTCD used all uppercase letters. And when they started doing the research on signing for freeways they realized drivers need to be able to see these signs from a long way off. So not only do we want to make them bigger, but want to use patterns so that drivers can start to recognize the shape of a word.

Credit Google Maps
Highway signs switched from all capital letters to mixed case to help drivers recognize the patterns of words before they could actually read the word.

So let’s say I’m driving north on I-95, going about 65 miles per hour, and I know that I’m looking for Hollywood Blvd. What really am I looking for?

So, you know that from a distance there’s going to be a bump at the beginning, there’s going to be a smaller bump where the two l’s are and then the y is going to drop down below the base. And you can look for that pattern before you can actual read the word itself, or the letters in the word.

In addition to being an expert in signage, you're also a civil engineer and a student of interstate and highway history. And you’ve mentioned before that from an engineering perspective the most obvious way to build a highway between two points is in a straight line. But I gather that history has taught us that it’s a little more complicated than just doing that.

Right, engineers like straight lines because they’re neat and tidy. And they thought that by making a straight highway it would be a safe highway. But when they built these roads that were straight as an arrow what they found out is people driving long distances on the highway, if it is a perfectly straight road, this phenomenon of highway hypnosis started to appear. Turned out there wasn’t enough of a challenge to driving to keep their attention. They’d end up falling asleep, driving off the edge of the road and suffering a crash. So we tend not put in highways and roadways that are perfectly straight.

Credit Kenny Malone
A very boring ending to a very long, important highway.

Now, one of the things that we’ve talked about having focused on our little 87 mile stretch of the 2,000 mile I-95, is that the end of that road in particular seems really lackluster in a way that maybe people wouldn’t expect. You’re driving south. All of sudden the road just dumps you out onto US1. And if you’re not looking for it you could totally miss it, but there is a sign -- just a green sign with an I-95 crest and the word “ENDS” below it. And that’s it.

Well, you know the idea is you want to keep traffic moving and you don’t want people stopping on the side of the road and taking pictures and you don’t want things occurring that could interrupt the traffic flow. Or at least the engineers don’t.

Gene Hawkins is a professor of civil engineering at Texas A&M University. He is one of the leading authorities on the evolution of signage and the Manual on Uniform Traffic Control Devices.

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