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Building 'The Big Roads'


Fasten your seatbelt, it's going to be a bumpy ride. Well, actually, it's going to be a pretty smooth ride thanks to concrete, asphalt, macadam and tarmac. Those are the materials that transformed the muddy trails and paths that once crisscrossed the U.S., transformed them into our massive system of superhighways, a system that in many ways now defines what the U.S. is.

Where would California be without the 405 - they say the out there - or Washington with no Beltway? And New Jersey, what's your exit? The American highways are such a part of our life that probably most of us never stop and think about how the world's largest public works project came to be, and it is the world's largest public works project. It's really a fascinating story.

It's filled with mythology like this: You probably heard that it was President Eisenhower, right, who was responsible for the system; it's named after him. Well, he knew virtually nothing about it until he stumbled upon it by accident while in a traffic jam.

It's a really fascinating story, and it's told in the new book "The Big Roads: The Untold Story of the Engineers, Visionaries, and Trailblazers Who Created the American Highways." Earl Swift is the author, and he is here. He joins us from HWRO in Norfolk, Virginia. Welcome to SCIENCE FRIDAY.

EARL SWIFT: Ira, thanks for having me.

FLATOW: You know, that is a big myth, is it not? We all say it was Eisenhower who created the superhighways.

SWIFT: Oh, it's been - I mean, the fact that it is named after him certainly leaves one with that impression. And I know I grew up believing that it was as much a part of his era as the polio vaccine and, you know, Telstar.

FLATOW: Right. Well, I'm going to quote from a page in your book where you put that all to rest, and you say the Federal Highway Act of 1921, signed into law in November, was the foundation for modern highway-building in the U.S. It remains the single most important piece of legislation in the creation of a national network, far more so than the later Interstate Highway Bill, which would not have been possible or necessary without it. Wow.

SWIFT: True, yeah. 1921 is really when we got modern, the modern partnership between the federal government and the states that enabled the country to build the network of highways we have today.

FLATOW: You mean the states were building their own roads, and the government was not involved on the state level?

SWIFT: The government was involved, but it was not - there was no coordination built into the planning between states. So you had states and federal government sharing the expense of building highways, but you had no overall plan for how these things would link up into a network that made sense. There was no rational, you know, vision for the thing. The 1921 act changed that.

FLATOW: And you talked about some of the visionaries, about that when Eisenhower got into office, there was a plan that had been well thought out, and the whole highway system put on paper already, and he didn't even know about it.

SWIFT: This had already been authorized by Congress. We had an interstate highways system already approved, already on, you know, on the books. The only thing it lacked was money. And in fact it had already received a couple of years' worth of funding, although at a token amount at that point.

So it was a done deal in every important respect, in planning, conception, in routing. You know, where these highways would go had already been decided, what they'd look like, you know, how fast you'd be able to go on them and where you'd be able to go on them.

FLATOW: And you told a really interesting anecdote about how Eisenhower stumbled on the plan in a traffic - stuck in a traffic jam one day.

SWIFT: Well, that's one version of the story. He - of course when he got stuck in that traffic jam, that would have been in 1957 or '58. He was well aware of the system by that time. He had signed the act that had financed it. What he wasn't aware of when he ran into that traffic jam in suburban D.C. was that the interstate highway system that he conceived of, that he thought he was signing into law, was very different from the interstate highway system that had actually been planned back in the '30s and '40s and authorized by Congress.

He had no idea that that system would venture into the cities. In fact, he was very much against that.

FLATOW: You're listening to SCIENCE FRIDAY. I'm Ira Flatow. We're talking about the creation of the superhighway system in the United States, talking with Earl Swift, author of "The Big Roads: The Untold Story of the Engineers, Visionaries, and Trailblazers Who Created the American Superhighways."

And this book is so chock-full of little anecdotes and stories and stuff. It's hard to know where to begin. Let me begin or continue by asking you: Who would be considered then the great father of our superhighway system? Who would you credit? I know you talk a lot about Thomas McDonald(ph) as being...

SWIFT: Thomas McDonald would probably get my vote as the first among equals of the triumvirate of men (unintelligible). It was an evolution. You know, the interstates evolved from the numbered U.S. highway system that dates to the mid-'20s. Those evolved from a very primitive network of mostly dirt auto trails that we had throughout the teens and early '20s.

It really started, for my - for the purpose of coming up with a line that makes sense with a guy named Carl Fisher(ph), I think - he was an Indiana wild man and speed demon, a bicycle racer, auto dealer. He marketed the first practical automotive headlight, which made him a millionaire, and he built the Indianapolis Motor Speedway with his winnings and then singlehandedly, pretty much, built the city of Miami Beach and along the way convinced a bunch of his automotive buddies to finance a rock highway from New York to San Francisco, the Lincoln Highway, which they did in fact build.

And that effort inspired businessmen in other cities to get behind private-sector road building as well, and that's how we got this primitive network of auto trails that sprung up in the late teens.

McDonald came in as the head of the federal road-building effort in 1919, a job he kept for 34 years. He finally retired in 1953. And he turned that primitive network that Fisher and company had conceived into a rational numbered network, a real grid that made some sense, and then conducted, oversaw the research in the '20s and '30s that spawned the interstate system and rode herd on the proposal that became the rough blueprint for the interstate system.

And then his protege, a guy named Frank Turner, turned that vision into the concrete and steel that started to sprout around the country in the '60s and '70s. Those three.

FLATOW: Yeah. And then they had to come up with a numbering system. That's fascinating how you describe how they decided how to number the highway.

SWIFT: Well, they did, because back in the days of the auto trails, the long-distance roads in America all had names, like the Lee Highway, the Lincoln, the Arrowhead Trail. And they identified themselves - if you were a driver, you knew when you were on a - on the road you were on because it had a signature color scheme, and they painted that color scheme in rings on telephone poles.

And, you know, they literally blazed the trail that you followed. But after a while, it became so unwieldy because you had multiple trails overlapping - you had 250 trails around the country, 64 in Iowa alone - and you couldn't keep track of where you were. I mean, the telephone poles were painted from ground to 15 feet up, and trying to figure out one color scheme from the next became a dangerous distraction.

So the feds and the state stepped in and decided to take the private auto trails, the associations that promoted these trails, out of the road-building business. And they came up - they assigned a committee to come up with a numbering scheme.

And a guy named E.W. James probably deserves the most credit for coming up with the scheme they devised in 1926, which was that all north-south highways would be numbered with odd numbers. All east-west highways would have even numbers. And the lowest numbers of each would be in the far northeast corner of the country, up in Maine.

So numbers would increase as you went west and south, and it had the advantage not only of being expandable - you know, you could always add more numbers to the system as you built new highways - but it also allowed a motorist to figure out where he was based on an intersection between these, you know, two of these highways. He could roughly kind of pinpoint - you could triangulate your position in the lower 48.

The interstate system took that same idea and just used a mirror image of it – again, odd numbers are north-south, even numbers east-west. But the lowest numbers are down in San Diego, and they increase in number as you go east and north.

FLATOW: And then you have the triple digits, which showed there was like a spur, like if you had 95, 195 led into that.

SWIFT: On a three-digit number, the first number, if it's an odd number, denotes a spur. It means that it connects with the main highway only in one point. An even number means that it's a loop and that it connects in two places.

FLATOW: And that gave rise to the Beltway.


SWIFT: Yes, it did.

FLATOW: But you talk about an interesting character, architect Lewis Mumford, who was very influential in those days, who started out as a great proponent, defender of the highway system, until he saw the havoc it was wrecking(ph) as people wanted to move it into downtown urban areas. And then he turned around, changed his mind.

SWIFT: Mumford is a very interesting guy because he did a complete 180. He - in the summer of 1931, he co-authored a piece in Harper's with a friend of his named Benton MacKaye, in which they advocated what we would now consider a limited-access, high-speed expressway. There were none of them in the country at the time. So this was pretty theoretical stuff that they were advocating.

But they described in this piece, you know, the modern interstate experience, pretty much, with great separated intersections, with development and access to the highway only at certain points. And you know, he - the interesting thing here is that MacKaye, his co-author in this, was also the guy who proposed the Appalachian Trail a few years ago, or a few years before that.

Over the course of the next 25 years, after this story appears - and they were - there were a number of thinkers who were, you know, kind of dovetailing on this idea of limited access at the time, but over the next 25 years, Mumford completely shifted his thinking on highways.

And as you say, it was especially when he saw the collateral damage caused by trying to ramrod a, you know, 200, 300 foot road right-of-way through a densely settled older city, especially in the east...

FLATOW: And in the poorest neighborhoods he to try to get - and people...

SWIFT: Most often. But, you know, in the case of some road projects, weren't real picky about what kind of neighborhood they blasted through, and that caused Mumford a great deal of heartache, as did his realization over time that building more roads didn't alleviate traffic congestion, it just created more congestion on newer roads.

And he came to recognize, earlier than most people, I think, that highways are almost like mountains. They create their own weather. They fill up as quickly as you build them.

FLATOW: We're going to take a short break. We'll be right back to talk more with Earl Swift, author of "The Big Roads." Stay with us.


FLATOW: You're listening to SCIENCE FRIDAY. I'm Ira Flatow. We're talking about highways with Earl Swift, author of "The Big Roads." One of the most fascinating aspects of your book, because it interests me so personally, is concrete.

SWIFT: Well, you're the first person who's said to me, Ira, that that is the part of the book that most interested them. So I'm glad to hear it because I was fascinated by concrete. I really was, actually.

FLATOW: It never stops curing, I understand. But that's another story.

SWIFT: That's true, it just cooks along. I found out a lot more than I ever expected to know about concrete in the course of doing the book. And one of the things that really surprised me is that this is an ancient technology that we just kind of lost for hundreds of years. You know, this was something that the Romans were very adept at using, and yet we for the entire first millennium and right up until really the opening of the 20th century kind of just somehow misplaced that technology completely and didn't get it back in full until 1918.

An American engineer named Duff Abrams, in 1918, came up with the very simple recipe for modern concrete. There had been a lot of competing theory about what constitutes the correct mix for concrete's various components, and there are only three components.

There's cement, you know, Portland cement. There's water, and there's aggregate, which is sand or gravel or whatever it is that you mix to give it body. No one had been able to come up with a way to properly regulate the mixing of this so that you'd get a predictable result.

And Abrams was able to do that by just pointing out that after putting together 50,000-some-odd batches of concrete, he was able to say that the only thing that really determines the strength of concrete is that you use as little water as you possibly can in mixing it.

FLATOW: Just enough.

SWIFT: Just enough to make it plastic so that you can mix it. Anything more, and its strength just drops off a cliff.

FLATOW: And you talk about the early roads being made out of macadam.

SWIFT: Macadam is just, it's gravel of various types, various sizes. Usually you lay down big gravel, and then you lay down little gravel on top of it. You roll it, and voila, you have a macadam road. And it dates from the 1820s, 1830s and takes its name from a guy, John McAdam, who developed the process.

And really what American engineers brought to it was adding either tar or asphalt to the macadam to create bituminous macadam, and that's what we now know as blacktop.

FLATOW: Or tarmac, tar and macadam.

SWIFT: Tarmac would be the tar version. Yeah, tar is basically just a coal derivative. It's a fake asphalt.

FLATOW: See what you learn from this book. I mean - Susan(ph) in Alexandria, Virginia, hi Susan.

SUSAN: Hi, Ira. I always heard that Eisenhower, being of a military mind, required that there be these long, straight passages on the interstate system, say a mile long, that could be used as runways in case of some sort of national emergency, to be used in a military way. Is that true or urban myth?

FLATOW: Good question.

SWIFT: That is - Susan, that's sadly an urban myth. It's such a good story. It's a shame it is.


SUSAN: Well, it's kind of a good idea.

FLATOW: Didn't he see in World War II the great autobahns the Germans had when he was over there and say I want some of that stuff?

SWIFT: Well, he sure did, knowing that, of course, we already had something on the books back here. But in fact the Air Force would have loved to have seen that, I think. And they approached the Bureau of Public Roads about having a look to see whether it was possible to incorporate an emergency runway system into the interstates.

And the federal highway folks just found that it could not be done...

FLATOW: In Europe - they have some in Europe, do they not, some of the highways?

SWIFT: Well, that was - of course you'd got to understand the autobahns were designed to be military roads. They were not designed to move people and commerce. I mean, they were - when they were opened, nobody in Germany had a car. The only people using them were trucks full of soldiers and tanks, and that was amply clear to all of the American highway officials who went over to take a look at them.

They admired their construction and design, but to a one, they came away concluding that something like that wouldn't have a lot of utility in the United States because, you know, it was designed to move the German army to the country's frontier so they could wage war on their neighbors and pretty clearly designed to do that.

FLATOW: You've seen a lot of highways and byways. Can you give us an idea of what the state of America's superhighways is today?

SWIFT: It's a bit troubling, really. Of course it varies from state to state. These are state highways. The U.S. interstate highways system is not owned by the federal government. You know, the system is now at or nearing its expected service life and will require a great infusion of capital in the coming years to stay useful, to stay in one piece.

We put a tremendous load on this thing. This - the 47,000-mile system constitutes 1.2 percent of our highway mileage, and it carries 25 percent of our traffic. So it's just an incalculable amount of wear that we subject these roads to, and we simply have not done a very good job in quite a few states at making sure that it's up to - will to continue to be up to the task.

What we'll see happen if isn't forthcoming to fix it is the bridges will be downgraded in what they can carry, and they'll become far less useful, and eventually you'll see stretches of the highway subjected to the same constraints.

FLATOW: They'll close them?

SWIFT: They will limit the amount of weight they can carry.

FLATOW: So trucks, heavy trucks won't be able to go on them.

SWIFT: Which is an awfully big piece of the reason they're useful.

FLATOW: And it's why the interstate highway was built in the first place.

SWIFT: It's a huge piece of the argument for them, you bet.

FLATOW: To go from big city to big city, as opposed to Eisenhower who thought they should be going to little towns. That's why he was so surprised.

SWIFT: Yeah, he envisioned kind of an autobahn system that avoided the cities. You might be able to get into a city off of the interstates system, on a spur, but the system itself would avoid the cities, and he was very surprised when he found that that wasn't the case. The concrete was already being poured when he found that wasn't the case.

FLATOW: Well, there are a lot of great, big surprises in your book, Earl, "The Big Roads: The Untold Story of the Engineers, Visionaries, and Trailblazers Who Created the American Superhighways." With Earl Swift. We've only had a fraction of the time we need to cover this book.

And it's a great book, and it's all my geeky stuff in it, too, Earl, so...


SWIFT: Well, thank you.

FLATOW: Thanks for the details. The beauty is in the detail.

SWIFT: Thanks so much for having me.

FLATOW: One more time, Earl Swift, author of "The Big Roads: The Untold Story of the Engineers, Visionaries, and Trailblazers Who Created the American Superhighways." Transcript provided by NPR, Copyright NPR.

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