Highway Signs

The town of Bunn, North Carolina, is easy to miss. It occupies a total area of just half a square mile, and it’s home to fewer than 330 people. Most of the surrounding land is used to grow tobacco and soybeans. But off the main road, behind a series of chain link fences and secure gates, is the state’s primary manufacturer of highway signs.

Inside the plant, workers are busy shearing giant aluminum panels, cutting sheets of green adhesive, and measuring out the spacing between letters. And outside in the shipping yard, the plant’s general manager, Lee Blackman, is admiring a row of completed products.

BLACKMAN: This sign right here is 12 foot tall. This is going somewhere on Interstate 95 in North Carolina.

This facility makes all kinds of road signs: stop signs, yield signs, construction signs. But its biggest products — both by size and revenue — are those huge green signs that loom over you on the highway.

BLACKMAN: That’s going to give you information about what road you’re on right now, the intersections that are coming up, what is the next town coming up, the exit and so forth.

Signs like this are all over American highways and freeways. There are literally  millions of them, and they’re so familiar that many of us don’t stop to think about where they come from — or why they look the way they do. Behind every highway sign, there’s a long and winding road of economic decision-making.

ROACH: We want to make sure that we can get a good quality product because we want it out there for 20 years. We’ve got to be good stewards of the taxpayers money.

For the Freakonomics Radio Network, this is The Economics of Everyday Things. I’m Zachary Crockett. Today: Highway signs.

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Back in the early days of the automobile, driving on American roadways was a free-for-all.

HAWKINS: There was no coordinated effort to manage the movement of vehicles, whether it be through road construction, a connected network of roadways, highways, traffic control devices.

That’s Gene Hawkins. He works for the forensic engineering firm Kittelson, and he’s a professor emeritus in the department of civil engineering at Texas A&M University. He’s one of the foremost experts on the history, design, and installation of traffic signs.

HAWKINS: The vehicles back then would not be used to travel long distances anyway. And as the ability to travel longer distances increased, they created these trail systems, which were typically run by trail associations.

These informal networks of roads were a predecessor to the highway system in America. And along these roads, there were very rudimentary ways of telling drivers where they were, and what was up ahead. Most of these signs were hand-painted. Some had words; others had symbols. They were made from an assortment of materials in all different sizes and shapes, and the signs were different from place to place.

HAWKINS: I’ve seen pictures of stop signs that looked like coffins, signs with skull and crossbones on them.

As people started driving further and crossing state lines, they didn’t know how to interpret all the markers they saw.

HAWKINS: People started encountering these inconsistencies in signing and signals and markings, and the state highway department people recognized we need to do a better job of providing a consistent, uniform system of traffic control devices.

In the 1930s, these efforts culminated in the Manual on Uniform Traffic Control Devices, or MUTCD for short. It provided a set of standards for traffic control devices across America’s growing system of roads. Today, it’s run by the Federal Highway Administration, and every state in the U.S. adheres to its guidelines. It’s nearly 1,200 pages long. And it lays out the ground rules for more than 500 signs, markings, and signals — everything from the octagon shape of stop signs to the precise size of an exit sign on the freeway. These rules are determined by the National Committee on Uniform Traffic Control Devices. Hawkins serves as the committee’s chair.

HAWKINS: The MUTCD gets into issues such as the design of the signs. Typically we’ll give some indication on when or how to use the device.

Technically a “highway” sign refers to any type of sign that communicates something to drivers on the road. And the MUTCD breaks these signs down into three categories.

HAWKINS: There’s regulatory signs which tell you what to do. It expresses the law, like a stop sign or speed limit. There are warning signs, and those are yellow diamond signs which warn you of a potential hazard, like a curve in the road or a pedestrian crossing. And then there are guide signs which give directions.

Guide signs are those enormous placards on the freeway that tell you which exits, or intersecting highways, are coming up, and how far away they are. And everything you see on one of these signs is a calculated decision, starting with the font. Most signs use a special sans-serif typeface that’s unofficially called Highway Gothic. It’s almost exclusively designed for highway signage.

HAWKINS: The spacing between the letters in the highway alphabet is much greater than the spacing between the letters on a printed page for reading.

The words on these guide signs are almost always set in mixed case, with initial capitals followed by lowercase letters. There’s a good reason for that.

HAWKINS: If you know what city name or street name you’re looking for, you could recognize that it was on a sign even before you could read it, when it’s mixed case. For example, my name Hawkins — he H sticks up in the K sticks up. The word English — the E sticks up, the G descends and the L sticks up. So if you’re looking for the city “Hawkins” or the road “English,” you have a shape that you’re expecting to see, and you can see that shape from further away than you can actually read the letters. And that was recognized as a real advantage when the traffic is moving at 70 miles an hour.

There are also guidelines around the size of the font on highway signs. And from below, it’s hard to grasp just how big the characters are.

HAWKINS: If it’s an overhead sign, it’s 20 inches for a capital letter. So the letter is almost two feet tall. And the general rule is that the space between lines of text is going to be equal to the height of the line of text. So it’s very easy to have a freeway sign that may only have 3 or 4 lines of copy that could end up being ten feet tall.

Then, there’s the color of the sign. In the 1950s, the federal government looked into the legibility of black, blue, and green signs. Officials staged a test with hundreds of motorists on a road in New York and found that 58 percent of drivers preferred green. Turns out, the color green has another benefit, too. It provides the best base for retroreflectivity — basically, what makes signs legible when they’re illuminated by a car’s headlights in the dark. The reflectivity of signs has come a long way. Engineers initially used something called cat’s eyes — tiny marbles embedded in each letter on the sign. These have since been replaced by reflective sheeting that covers the whole sign.

HAWKINS: Most of the sign sheeting made in the United States is what’s called micro-prismatic sheeting. And essentially, if you look at a bicycle reflector, it looks like a series of ridges inside. And it is a similar structure in micro-prismatic sheeting, just really, really, really small.

Now, not every sign on the freeway is green. Some of them are brown. Those are typically used for tourist attractions, or recreation points, like state parks. And every now and then, you’ll also see a blue sign full of corporate logos. Those are called service signs, and their purpose is to tell you what kinds of services and businesses are coming up — say, a Chevron gas station in 2 miles, or an Arby’s at the next exit. These are actually ads, and businesses pay for the real estate.

HAWKINS: In most states, the logo signing program is run as a program where they contract that with a business who goes out and collects money from those businesses that want to put a logo. And sometimes they have to do a lottery. Sometimes it’s a bidding process. The businesses that install those signs and get the logos and everything, they pay the state agency some percentage or flat fee for the ability to do that.

To qualify, a business usually has to fall into one of a number of categories: gas, lodging, food, camping, attraction, or pharmacy. And the fees vary from state to state. In Arizona, a placement can range from $1,100 in a less populated area to more than $6,000 in a busier urban location. In other states, like North Carolina, it might only be a few hundred bucks. For state transportation departments, service signs can bring in millions of dollars in revenue.

But most highway signs aren’t lucrative for the public entities responsible for them. Making them is an intensive and costly endeavor — one involving precision, specialized equipment, and an unusual labor pool.

That’s coming up.

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It’s estimated that there are more than 40 million traffic signs on American roadways. There are dozens of companies that make the smaller ones, like stop signs or speed limit signs. But few manufacturers are capable of producing the enormous green highway guide signs. When a state transportation department needs a new one, the job goes to someone like Renee Roach.

ROACH: I work for the North Carolina Department of Transportation. I am the state signing and delineation engineer.

Roach has a big job to go along with that big title.

ROACH: We maintain over 80,000 miles in North Carolina. Any signs, we lay out exactly where they need to go, what do they need to say, destinations, route markers and things like that. Any of the pavement markings that are out there on the road, we also place — the size, the color, the location of those.

Most highway signs have a sticker on the back with the dates that it was manufactured and installed. Roach knows exactly how long every sign has been on the highway, and when it probably needs to be replaced. A good sign might last anywhere from 12 to 20 years before the natural elements start to degrade it. But sometimes, replacements happen far sooner.

ROACH: There is vandalism. You’d be surprised at how much vandalism. They may get hit or destroyed. When a project comes through, maybe the destination needs to change on those.

Whenever Roach needs a new highway sign, she turns to a trusted supplier.

ROACH: The vast majority of our signs are coming through Bunn.

In North Carolina, nearly every highway sign in the state comes from the sign plant in the small town of Bunn. Earlier this year, we took a trip out there to see the manufacturing process for ourselves.

CROCKETT: Is this whole thing we’re looking at here one sign? 

BLACKMAN: Yes, it is. It’s pretty awesome. When we get out in the yard, I’ll show you some really big signs.

As a general manager who oversees the plant, Lee Blackman is in charge of running day-to-day operations. We talked to him on the factory floor, over the sounds of welding torches and miter saws.

BLACKMAN: Our plant is actually divided into two different halves. This is what we call the project end, where we’re manufacturing mostly your big overhead signs that you see there. The other end is what we call the maintenance side of the plant. That’s where your smaller signs — let’s say your 30-, 36-inch stop signs that you see in a rural setting. Your standard speed limit signs are back there.

The process for making a highway sign begins with a detailed blueprint, sent over by Renee Roach at the North Carolina Department of Transportation.

BLACKMAN: That’s got the exact specifications that D.O.T. wants for this sign. Whether it’s the type of sheeting, the color of sheeting, the overlays, different things like that, it’s all going to be on that. So this routing sheet is going to follow this sign all through the process and to the end.

The first step of the fabrication process is selecting the right kind of aluminum for the job.

BLACKMAN: We use four different gauges or thicknesses of the metal. Our largest sheet that we’ll use is 48 by 144, which is four foot wide, 12 foot long. 

The workers haul these huge sheets over to the shearing department, where they’re cut to size. Sometimes, signs are so big that they have to be split up into as many as 14 different panels.

BLACKMAN: When the contractor gets it out on the job site, they’ll put it together like a puzzle. 

The sheared metal is sanded down to get rid of any blemishes or rough patches. Then, it’s coated with green reflective sheeting.

BLACKMAN: There’s no paint on the sign — it’s all sheeting and translucent ink. This piece of equipment is called the squeeze roll applicator — the machine is set to a specific pressure and that will directly apply the sheeting to the piece of metal.

Then comes one of the more technical parts of the job: putting the letters on the sign. For large highway signs, each letter is printed individually and placed by hand according to very strict measurements.

BLACKMAN: What he’s doing now is he’s spacing out the horizontal measurements for the line of copy. He knows how far from the bottom these letters are going to be, how far from the top. And he’s setting all that up. He’s going to handle every one of these letters individually. It tells you the exact distance from one letter to the next, from the edge of the sign coming up to the first letter.

CROCKETT: So you know everything, down to the spacing of the font.

BLACKMAN: You know, the spacing, the different size fonts. And that determines too: you know, bigger sign, bigger fonts, smaller sign, smaller font. These letters can only be off an eighth of an inch.

CROCKETT: That’s not a whole lot of leeway.

BLACKMAN: It’s not a whole lot of leeway.

From start to finish, it can take around 12 hours to finish a single large highway guide sign. Once a sign is done, it’s taken out into the storage yard. There, racks upon racks of enormous highway signs are lined up, to get transported all over the state of North Carolina.

BLACKMAN: These signs right here are ready to go — whether it’s going to a specific project on a specific road, or whether it’s what we call a division, where it’s going to go to a specific D.O.T. division.

Good highway signs don’t come cheap. North Carolina’s Department of Transportation pays around $42 per square foot for the sign itself. Depending on the size, that could run anywhere from $1,400 for an exit sign to $8,500 for a large guide sign. Then, there’s installation. If the sign is ground-mounted, labor and support beams might run an additional $18,000. If the sign has to hang over the road — either on a cantilever or a structure that spans the entire highway — that cost could be as high as $200,000.

But in North Carolina, there’s a catch that saves the state of a ton of money. The Bunn sign plant is located inside a prison. And Correction Enterprises, which runs the plant, is staffed by incarcerated individuals. That’s a huge benefit for the state budget, because it allows Renee Roach to get a good deal on signs.

ROACH: They can just really generate a lot of those signs really quickly for a fairly inexpensive price.

As it turns out, many of America’s highway signs are produced by prisoners. And it’s not just signs. Correction Enterprises has plants all over North Carolina that make reading glasses, furniture, canned goods, license plates, and cleaning supplies. It’s part of a prison labor system that produces billions of dollars of goods every year.

On next week’s episode, we’re going to look at that system — one that employs 800,000 people at wages of pennies per hour, or even nothing at all.

GALEN LEE SMITH: The work’s real tough. So, you know, everybody will tell you that they wish they made more. I wish I made more. But the government decides on what we should make, and that’s what it is. 

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For The Economics of Everyday Things, I’m Zachary Crockett. This episode was produced by me and Sarah Lilley, and mixed by Jeremy Johnston. We had help from Daniel Moritz-Rabson.

HAWKINS: My father was a traffic engineer, city of Houston.

CROCKETT: So you guys are a Texas traffic sign dynasty?

HAWKINS: I don’t know if I’d call it a dynasty. If it had been a true dynasty, one of my kids would have followed in my footsteps and that did not happen.