Speaker 1: Hey, welcome to Invention. My name is Robert Lamb and
Speaker 1: I'm Joe McCormick and Robert. I don't know if you've
Speaker 1: ever had this experience, You've ever been out walking in
Speaker 1: nature and you decided to veer off the path for
Speaker 1: some reason, Maybe you saw something interesting way off there
Speaker 1: in the distance you wanted to go check it out,
Speaker 1: only to immediately discover, to your own humiliation, how difficult
Speaker 1: it is to walk through uncleared terrain. Oh yeah, yeah,
Speaker 1: I've definitely had this experience before. And that's not even
Speaker 1: getting into you know, issues of ticks and other parasites.
Speaker 1: Oh yeah, there's there's the tick problem, definitely. But like,
Speaker 1: unless you're somebody with a particular class of outdoor hobbies
Speaker 1: or lines of work, you would probably be so embarrassed
Speaker 1: to realize how much of your life you spend on
Speaker 1: pre selected traversible pathways like the floor of your house
Speaker 1: or workplace, the sidewalk to the door, the sidewalk down
Speaker 1: the road, the road itself. Even when you go out
Speaker 1: in nature, it's really likely that you probably spend most
Speaker 1: of your time out there following some kind of forged
Speaker 1: or trodden pathway. And if you get off the path.
Speaker 1: Planet Earth almost immediately transforms into this unruly and difficult
Speaker 1: place with uneven footing and branches and rocks and vegetation
Speaker 1: blocking your path, sudden drop off, steep inclines. This is Earth,
Speaker 1: and this is what a large part of the surface
Speaker 1: of Planet Earth is like. And much of it is
Speaker 1: just not made to be quickly and easily traveled over.
Speaker 1: It's funny, how even if you go out and spend
Speaker 1: a decent amount of time in nature, you can mostly
Speaker 1: overlook this fact just by staying on the path. So
Speaker 1: that's what we wanted to look at today. Something we
Speaker 1: don't often even think of as a human invention, but
Speaker 1: in a way certainly is the roads we travel. That's right,
Speaker 1: it's a it's it's really an essential part of the
Speaker 1: world that we have created. Um. But however, if we
Speaker 1: if we want to understand the human history of roads,
Speaker 1: and even get into the pre human history of roads,
Speaker 1: we have to acknowledge the work of our of our
Speaker 1: non human relatives, of the work of animals, because because
Speaker 1: we do have animal paths. To consider the trails left
Speaker 1: by say, deer in the forest, the buffalo roads across
Speaker 1: the western plains of North America, animals on the move
Speaker 1: from one area to another had to push aside vegetation,
Speaker 1: and in the act of moving they end up trampling
Speaker 1: down the earth beneath their weight. And we're talking about
Speaker 1: a lot of weight when we're considering wide ranging megafauna,
Speaker 1: you know, some of which we still have today, but
Speaker 1: we had even more of in prehistoric times. I guess
Speaker 1: before there were the cattle roads where the orax roads
Speaker 1: or something. Yeah, and of course when other animals came
Speaker 1: along in their wake. Uh, these paths were there, and
Speaker 1: they often represented the swiftest, least least obstructive way to
Speaker 1: get from one place to another. Yeah, it's certainly interesting
Speaker 1: to think about animal trails as being a tight of
Speaker 1: geomodification or adaptation of the landscape itself to the organism. Now,
Speaker 1: a lot of the ways that organisms survive are by
Speaker 1: adapting to the landscape around them. But sometimes they survive
Speaker 1: by changing the landscape to better suit them, and they
Speaker 1: don't necessarily do this consciously. Is just their activities bring
Speaker 1: this about the big examples or things like beaver dams.
Speaker 1: Beaver dams is just altering the immediate environment or or
Speaker 1: even looking to mega fauna that such as an elephant
Speaker 1: that may push push down trees and other vegetation. Yeah,
Speaker 1: but of course we can see paths emerging that in
Speaker 1: some ways play some of the same roles. Yeah, now
Speaker 1: I do I do want to drive home here though
Speaker 1: that even though animal trails are are often brought up
Speaker 1: as being sort of the pre human origin of roads
Speaker 1: and human pathways and certainly seem to play a role
Speaker 1: in them. Uh, there are some who take issue with
Speaker 1: with giving animal trails too much importance, are arguing that, well,
Speaker 1: animals don't actually follow consistent paths all the time, so
Speaker 1: it's not a you know, a definite connection here, but
Speaker 1: it is one that is pointed out in a lot
Speaker 1: of the literature. And speaking of the literature, one of
Speaker 1: the books that we look to for this episode is
Speaker 1: a book by the title of Ways of the World,
Speaker 1: A History of the World's Roads and of the Vehicles
Speaker 1: that used Them, by Maxwell Gordon lay On, Australian civil engineer,
Speaker 1: published in nineteen two. In the book, lay says that
Speaker 1: you know, on this whole issue of animal paths, it
Speaker 1: really depends on the environment. He says, quote difficult to
Speaker 1: rain or dense of vegetation in fertile areas would certainly
Speaker 1: have required narrow and specific animal ways. So even if yeah,
Speaker 1: you can say that, uh, you know, animals aren't gonna
Speaker 1: always follow consistent paths, there are going to be environments
Speaker 1: where there is like one best way to get from
Speaker 1: point A to point b. If point a to point
Speaker 1: B is indeed a path that needs to be navigated
Speaker 1: by animals. One way to see an analogy here is
Speaker 1: if you ever look at the the desire paths that
Speaker 1: form along a college campus or or yard of a
Speaker 1: well populated building or something. Do you ever see these
Speaker 1: at College Robert where there would be like paved pathways,
Speaker 1: but then branching off in a shortcut between two places,
Speaker 1: there would be a place where the grass was just
Speaker 1: beaten down and there was a dusty dirt. Oh yeah,
Speaker 1: it's generally it's kind of a breakdown in planning because like,
Speaker 1: clearly you did not plan out the best paved route
Speaker 1: for for foot traffic. Clearly foot traffic wants to go
Speaker 1: this way. But it's kind of beautiful watching those things
Speaker 1: emerge because nobody planned it that way. Just as you're saying,
Speaker 1: even the students didn't plan it that way. Just over time,
Speaker 1: enough people make the same decision about where to go
Speaker 1: and how to get there, that these natural pathways emerge
Speaker 1: until someone throws up a hedge or something. So eventually
Speaker 1: you have a few species of hominids that come along,
Speaker 1: and they distinguished themselves in intelligence, and they start forging
Speaker 1: their own trails, often incorporating animal trails whenever it makes
Speaker 1: sense as well. So, yeah, if the trail all of
Speaker 1: the megafauna uh is there, they may use it, but
Speaker 1: they may also uh beat down their own paths as well.
Speaker 1: So you know, they would have navigated by doing this,
Speaker 1: they would have navigated difficult drain bodies of water. And
Speaker 1: prior to the coming of Europeans to to the America's
Speaker 1: the native people's here had they had their own complex
Speaker 1: system of foot trails by which they could travel the land.
Speaker 1: In his book, uh Lay points out the Nachez Trace
Speaker 1: four dred forty mile or seven hundred kilometer trail that
Speaker 1: goes from Nachez, Mississippi to Nashville, Tennessee, and it was
Speaker 1: used by native peoples for centuries and it was said
Speaker 1: to have, you know, been originally created by buffalo heading
Speaker 1: north to Salt Licks in the area of what is
Speaker 1: now Nashville, Tennessee. Yeah, and this highlights something you might
Speaker 1: not immediately think about with roads, because roads not only
Speaker 1: allow you to move more easily by providing a clear
Speaker 1: path on the surface c C to walk on, they
Speaker 1: also help you know where you're going. And this could
Speaker 1: even be the case for animals. Right many animals have
Speaker 1: been built navigation capabilities that others don't. As a large
Speaker 1: bipedal primate, just try to find your way around in
Speaker 1: the world without a compass or a map or a road,
Speaker 1: you're probably gonna have kind of a hard time of it.
Speaker 1: And you can also consider the fact that even if
Speaker 1: you're not following a familiar road to get somewhere specific,
Speaker 1: you can follow any road to eventually get somewhere significant.
Speaker 1: Like people don't usually build roads to nowhere, and that
Speaker 1: applies to animals as well. Now in considering lands that
Speaker 1: have known the influence of humans for far longer than
Speaker 1: the America's, it has also been theorized that some of
Speaker 1: the the older winding roads in places like England have
Speaker 1: their roots in wild animal pathways leading to fords and
Speaker 1: watering holes. And of course, in the case of many
Speaker 1: of these ancient trails. Uh, they might remain somewhat fluid
Speaker 1: for a number of reasons, because you have shifting waterways.
Speaker 1: Trees are gonna fall, beavers are going to do their things,
Speaker 1: storms are gonna uh add chaos as the scenario, So
Speaker 1: any number of things might occur that that that alter
Speaker 1: the shape of the path. And of course additional changes
Speaker 1: would come as humans uh continue to develop their their
Speaker 1: their their primitive technologies. Right, they require more paths for
Speaker 1: their own meager footfalls. The cultivation of crops and animal
Speaker 1: husband husbandry would have increasingly created a world where certain
Speaker 1: areas had to remain off limits to animals, particularly to
Speaker 1: domesticated animals and other zones or you know, roads would
Speaker 1: need to easily and safely convey these creatures from one
Speaker 1: place to another. All right, we're gonna take a quick break.
Speaker 1: When we come back, we're going to continue along the road.
Speaker 1: All right, we're back now. Obviously, there is no single
Speaker 1: inventor of roads, so we can't point to uh dr
Speaker 1: Rogilus who came up with roads ten thousand years ago.
Speaker 1: Didn't happen, Sir Walter Rhodes, Uh, No, you know, we've
Speaker 1: already discussed the foot paths of early humans likely made
Speaker 1: use of animal paths to some degree. But then what
Speaker 1: happens again when humans transition out of their mere hunter
Speaker 1: gatherer lifestyle. What happens in the wake of the agricultural revolution,
Speaker 1: resulting in such innovations as domesticated animals and then eventually
Speaker 1: wheel and sledge constructions for dragging surplus crops, firewood, and
Speaker 1: other necessities around. Now, once you introduced the idea of
Speaker 1: wheeled vehicles, things changed significantly, And it's worth noting as
Speaker 1: an aside that the strange and fascinating fact that it
Speaker 1: appears the wheel was not invented for transportation until some
Speaker 1: time around the fourth millennium b C, like or something,
Speaker 1: which at first first exposure to this fact seems shockingly late. Right,
Speaker 1: Grain agriculture has probably existed since around nine to ten
Speaker 1: thousand BC, which means that roughly half the time humans
Speaker 1: have been farming, nobody had wheeled vehicles to move sacks
Speaker 1: of grain or whatever around. So, of course, maybe we
Speaker 1: shouldn't be surprised, given that wheels are a deeply unnatural invention, right,
Speaker 1: So many human inventions have some kind of analogy and nature.
Speaker 1: While there are animals that roll their bodies or parts
Speaker 1: of their bodies in various ways. Maybe the closest is
Speaker 1: the bacterial flagella, which nobody could have seen the microscope
Speaker 1: to see. See some of the more wheel like creatures
Speaker 1: in the Animal Kingdom. But even that's not really a wheel.
Speaker 1: There's just nothing in nature that operates on a wheel
Speaker 1: and axle, and we should definitely revisit the invention of
Speaker 1: the wheel future. That's a no brainer. We have to
Speaker 1: come back to that. But so, yeah, think about this,
Speaker 1: just thousands of years of agriculture and road in some
Speaker 1: way road based transport, at least some primitive forms of
Speaker 1: roads without wheeled vehicles on them. Yeah. Now, on the
Speaker 1: subject of domesticated herd, you might well require a dependable
Speaker 1: road to connect winter and summer grazing lands, and indeed
Speaker 1: we see examples of this in the Cannadas realists in Spain.
Speaker 1: These are drovers roads covering hundred and twenty five thousand kilometers.
Speaker 1: Another example of the the Welsh Roads of England that
Speaker 1: linked scott At Scotland and Wales to London markets. Again
Speaker 1: just moving domesticated animals from one place to another. Yeah,
Speaker 1: roads are necessary for the development of trade and in
Speaker 1: many ways you could say for the development of culture.
Speaker 1: I mean, almost everything that we think of in culture
Speaker 1: comes ultimately from the connections of people's to each other,
Speaker 1: you know, the meeting of different minds across distance, and
Speaker 1: that's all enabled by roads in trade. Yeah. And even
Speaker 1: though a lot of these roads change over time, obviously,
Speaker 1: and and you don't find a lot of paths that
Speaker 1: remain in use for just extended periods of time, but
Speaker 1: you do see these wonderful examples of some of these pathways,
Speaker 1: particularly in North America and Britain, where just they have
Speaker 1: centuries of wear and tear and they've essentially become a
Speaker 1: little trenches just from all the of the foot traffic.
Speaker 1: And that is is pretty amazing. Yeah. Though the Roman
Speaker 1: roads were dug out to be in with I believe
Speaker 1: or at least some of them were, right, like they
Speaker 1: would dig down a trench in a way to become
Speaker 1: the road. Oh yeah, And that's where we're getting in
Speaker 1: really into a serious construction of roads. And ultimately, that's
Speaker 1: what we need to talk about at this point, is
Speaker 1: when when you start constructing a road, it's not merely well,
Speaker 1: we sure did move those goats from from here to
Speaker 1: there enough times that there's the best way to do that.
Speaker 1: You know what, what happens when we get into the
Speaker 1: idea of of planning a road, manufacturing and reinforcing it,
Speaker 1: caring and maintaining it. When we started asking that question, well,
Speaker 1: Lay says that quote, uh, the creation of major lowland
Speaker 1: ways required a degree of engineering skill and organization that
Speaker 1: began to develop around four thousand BC. It points out
Speaker 1: that the oldest British quote planned and engineered pathways date
Speaker 1: back to Glastonbury, UK thirty three thousand b C. And uh,
Speaker 1: good local roads ultimately helped the Britains defeat the Roman
Speaker 1: legions in fifty five b C. And now. Of course,
Speaker 1: on the other hand, extensive, high quality roads are a
Speaker 1: major factor in the military success of the Roman Republic
Speaker 1: and then the Roman Empire right or really any any
Speaker 1: particular empire. I think back to episodes of of stuff
Speaker 1: double your mind that you and I did on the
Speaker 1: Inca and the important of the the Inca road system,
Speaker 1: which also incorporated uh, tremendously impressive rope bridges, and how
Speaker 1: that contributed to the success of the Inca. Yeah, great
Speaker 1: part of the power of the Inca Empire lay in
Speaker 1: its transportation and communication infrastructure. Yeah, and if you want
Speaker 1: to quickly convey your troops from one point in an
Speaker 1: empire or kingdom to another, especially across difficult terrain, in
Speaker 1: order to defend or expand a kingdom, um, you're going
Speaker 1: to need good roads. And indeed we see this reflected
Speaker 1: even in recent history, say the United States Interstate system
Speaker 1: in the early twentieth century, it was considered necessary for
Speaker 1: national defense. Yeah, definitely, and their more stable reasons that
Speaker 1: roads are necessary for for military purposes. I mean, one,
Speaker 1: of course, is to get your armies to places. That's
Speaker 1: the obvious one. But the other one is the thing
Speaker 1: that a lot of times people you know, when they're
Speaker 1: when you're playing your historical military games, like that, would
Speaker 1: Julius Caesar's army to feed the Mongols or something like that?
Speaker 1: You know, you're you're doing all that stuff. People like
Speaker 1: to think about commanders and weapons and fighting styles and
Speaker 1: all that, but they don't think enough about the real
Speaker 1: thing that makes or breaks a war campaign, which is
Speaker 1: supply lines, the ultimate gremlin of military history. The army
Speaker 1: marches on its belly, right, Yeah, and undersupplied army can't
Speaker 1: fight at full strength, and so the supply lines, how
Speaker 1: you get food and other major supplies to your troops,
Speaker 1: how you bring reinforcements to the front. I guess that
Speaker 1: all falls under the military category of logistics. But that's
Speaker 1: a huge part of the success of a military campaign.
Speaker 1: Now it's easy for us to get caught up in
Speaker 1: the you know, these sort of country roads. We've been
Speaker 1: talking a lot about a lot of cross country paths
Speaker 1: and roads. But as as Life points out in his book, Um,
Speaker 1: you know, going back to two ancient times, uh, you
Speaker 1: see roads as a necessity of city planning. As cities
Speaker 1: become a thing for for human beings, it becomes necessary
Speaker 1: to think about how people were moving around in them,
Speaker 1: what sort of of of streets or roads are present.
Speaker 1: And you see this in the work of the ancient
Speaker 1: Egyptians and various Middle and Near Eastern civilizations. Uh. The
Speaker 1: use of roads and sinning city plannings was discussed in
Speaker 1: the writings of, for instance, Greek city planner Hippodamus in
Speaker 1: Uh in later reference in the works of Aristotle and others,
Speaker 1: and sometimes city plans were based more on engineering, and
Speaker 1: other times there was a there was some element of mysticism,
Speaker 1: as well, which seems seems like it would be highly
Speaker 1: susceptible to mysticism the construction of roads, because it is
Speaker 1: this kind of complex like system of on language that
Speaker 1: you're laying out across the world. Roads appear in all
Speaker 1: kinds of myths and legends and religiously significance to worries.
Speaker 1: The Road to Damascus, the Road to m s the row,
Speaker 1: little red riding hood on the road to her grandmother's house. Yeah.
Speaker 1: How many um horror stories throughout history are essentially stories
Speaker 1: about what happens when you go off of the path
Speaker 1: or the road, right right, Yeah, Mirkwood in the Hobbit, Yeah,
Speaker 1: if they stick to the road, gentlemen, and you're not
Speaker 1: gonna encounter problems, don't go chasing elf lights into the dark. Now.
Speaker 1: Of course, we'd be remiss if we did mention one
Speaker 1: of the great roads, the Silk Road, an example of
Speaker 1: roads running into other roads to become more or less
Speaker 1: a single pathway dating back to roughly three kind of
Speaker 1: connecting various caravan routes across Eurasia. One of the all
Speaker 1: time grades. D Yeah, top top top five, top three.
Speaker 1: To be sure, all right, we're gonna take a quick break,
Speaker 1: but we will be right back. All right, We're back, okay. Now.
Speaker 1: One thing that certainly changes about road it's over time
Speaker 1: is that the original roads were just beaten down areas
Speaker 1: of earth, right and where the there where the cattle
Speaker 1: or the large bovids or whatever would push through. They
Speaker 1: trample down the ground and make it flat, and they
Speaker 1: push the vegetation aside, so there'd be a clear pathway
Speaker 1: going somewhere. But over time roads took on a more
Speaker 1: technological character. People were looking for better ways to make
Speaker 1: more reliable roads. Because you got a road like that
Speaker 1: that's maybe just some trampled down cleared earth. Maybe let's
Speaker 1: say you have some heavy rains. What you tend to
Speaker 1: find is that the road like that gets a little
Speaker 1: bit washed out in the roads. Yeah, I mean in
Speaker 1: in in our own neighborhoods here in Atlanta, we we
Speaker 1: have at least a few examples of this where we
Speaker 1: have an unofficial pathway and then what happens when it
Speaker 1: becomes a muddy wreck. And then you see some very
Speaker 1: amateur essentially road building where people are like, well I'll
Speaker 1: just dump a bunch of rocks in here, or I
Speaker 1: have some tire garbage that will really help things out. Yes,
Speaker 1: I will fix the path with a whole bunch of
Speaker 1: cans or something. Yeah. And it essentially this is kind
Speaker 1: of what we see in some of the the early
Speaker 1: corduroy roads or log roads that are that are created
Speaker 1: to deal with muddy terrain. Oh they're better than cans,
Speaker 1: I guess. But but essentially we're talking about placing logs
Speaker 1: perpendicular to the direction of the road. And examples of
Speaker 1: this sort sort of road date back at least four
Speaker 1: thousand years. Uh. There's the so called post track in
Speaker 1: Somerset levels, England, for instance. Uh. And it makes sense, right, Like,
Speaker 1: what what do you do if your your vehicle is
Speaker 1: stuck in the mud, right, just grinding, grinding the mud
Speaker 1: until you're buried. You get you get some sticks or law,
Speaker 1: you know whatever, pieces of wood and you put them
Speaker 1: under the tire. You want something to pull up on
Speaker 1: some traction. Yeah, you want to put something under the
Speaker 1: tire that will stay where it is when you're driving. Yeah.
Speaker 1: So that is essentially what say, you know the post
Speaker 1: track is lay mentions another one. He says the sweet
Speaker 1: track uses longitudinal log to support oblique crossed pegs which
Speaker 1: form a v uh every meter or so planks between
Speaker 1: these create a walking path. And this is the Sweet
Speaker 1: Path from near Glastonbury, which dates back to uh. Three
Speaker 1: thousand BC. Now, Robert, when did people first come up
Speaker 1: with the idea of the old the old popper the
Speaker 1: gravel road? Ah, you know, I was. I was thinking
Speaker 1: about this, and I was reading around in lays book
Speaker 1: and looking at a couple other sources on this, and um, yeah,
Speaker 1: it's one of these things that that feels like it
Speaker 1: should be pretty archaic, because again we come back to
Speaker 1: that idea, what do you do when the path gets muddy? Well,
Speaker 1: one solution is get some rocks and throw them on there, right,
Speaker 1: And that that clearly seems to have been something that
Speaker 1: would have been utilized by by our our ancient ancestors.
Speaker 1: But but when you start really thinking about gravel roads,
Speaker 1: it gets pretty interesting. We can really take the technology
Speaker 1: and the labor involved. For granted. For example, was recently
Speaker 1: in Costa Rica and we went up to Monteverde in
Speaker 1: the cloud forests and to get to Mount a Verde, Uh,
Speaker 1: you have to take this this winding road, and more
Speaker 1: and more of it is paved now, but there's still
Speaker 1: a stretch that is gravel and and these are these
Speaker 1: are good gravel roads. I don't want to cast any
Speaker 1: unnecessary shade on the roads of Costa Rica because uh
Speaker 1: uh you know, we never felt in danger or anything.
Speaker 1: You know, these are these are nice gravel roads. Uh,
Speaker 1: I mean, hey, I've been on some scary gravel roads
Speaker 1: in Georgia. Oh yeah, yeah, I mean, and if I'm
Speaker 1: being honest, like gravel roads in general like tend to
Speaker 1: wig me out, but probably unnecessarily so. But yeah, I
Speaker 1: think think about about what essentially a gravel road is.
Speaker 1: Instead of lining the road with wood, you cover it
Speaker 1: with dirter rocks or gravel, uh, taken from well, in
Speaker 1: today's cases, some sort of quarried area, right, but more
Speaker 1: likely in older examples you'll be talking about rocks from
Speaker 1: a creek bed. The problem, of course, is that gravel
Speaker 1: can be washed away and then you have you have
Speaker 1: this huge task of hauling it all the gravel back
Speaker 1: up and then distributing it where it needs to go.
Speaker 1: And this can be quite intensive. I mean, just look
Speaker 1: at modern cases. If you see any kind of maintenance
Speaker 1: going on, or you know, if you happen to get
Speaker 1: to see the creation of a gravel road, you're going
Speaker 1: to see the hauling and distribution via you know, massive
Speaker 1: pieces of equipment, dump trucks and what have you. Uh.
Speaker 1: And perhaps this is a major reason you tend to
Speaker 1: see more widespread use of gravel roads in say, early
Speaker 1: twentieth century US and twentieth century developing areas and nations
Speaker 1: as well, because it simply becomes cheaper to transport and
Speaker 1: dump all the necessary gravel, which is of course again
Speaker 1: now mind and transported on dependable roadways rather than just
Speaker 1: laboriously transported from stream beds to uh, you know, roadways
Speaker 1: that might be questionable in their own right. The age
Speaker 1: of the dump truck made it possible. Yeah, so think
Speaker 1: about that the next time you're on a gravel road.
Speaker 1: Realized that this is perhaps more of a modern conveyance
Speaker 1: than you're giving giving a credit for. Now. Of course,
Speaker 1: when we talk about like the best, the most modern
Speaker 1: examples of a road, you're gonna think of paved roads, right,
Speaker 1: These are the gold standard. I thought you were gonna
Speaker 1: say a rainbow road. No, but I guess a rainbow
Speaker 1: road would probably be paved as well, because the gravel
Speaker 1: rainbow road would just become distorted from all the traffic
Speaker 1: is that would be really difficult to maintain. And yet
Speaker 1: here's the thing. As modern as these fields, even though
Speaker 1: this feels like the height of modernity, these actually go
Speaker 1: back quite a long ways in human history as well.
Speaker 1: So you have stone paved roads that date back to,
Speaker 1: for instance, the Middle Eastern city of er Uh circa
Speaker 1: UH four thousand b C. You have brick paved roads
Speaker 1: in India that date back to three thousand BC, and
Speaker 1: we also see them in Malta from around two thousand
Speaker 1: to b C. Basically, as humans developed and improved the
Speaker 1: ability to cut stones and mix mortar, they crafted not
Speaker 1: only walls but roads, because ultimately, what is what is
Speaker 1: a road but a kind of wall that is laid
Speaker 1: on the ground. Right, the technology is not all that different, okay,
Speaker 1: But then there was also, i mean, the development of
Speaker 1: um what would you call it, the supporting infrastructure around
Speaker 1: the road. If you look at, say some of the
Speaker 1: stone paved Roman roads, you'll see that they not only
Speaker 1: had this paved surface, but they had protective elements like
Speaker 1: they had like retaining walls or ditches, you know, to
Speaker 1: get the right kind of drainage or protection from the
Speaker 1: road against the elements. Oh yeah, drainage. Drainage is key
Speaker 1: and and waterproofing. And this leads us to the bitumen roads,
Speaker 1: which are pretty pretty interesting page from the history of
Speaker 1: road technology. First, just a reminder, and what bitchuman is?
Speaker 1: It's the word I can never remember how to pronounce
Speaker 1: the American way. I think we say it the British way,
Speaker 1: which is bitumen. Yeah, it's it's it's a mouthful, but
Speaker 1: it's It's also the arguably the world's first petroleum product.
Speaker 1: It's a sticky, black viscus substance and uh. And when
Speaker 1: it's combined with mixed with sand and stone, you get
Speaker 1: essentially asphalt. But it was highly prized in the ancient
Speaker 1: world and for the longest it was primarily a Mesopotamian monopoly,
Speaker 1: and it's alid use in various endeavors things everything from
Speaker 1: art and cosmetics to just cocking your boat. Uh. Didn't
Speaker 1: we talk about it on an episode of Stuff to
Speaker 1: Fill Your Mind? Is a potential constituent of Greek fire.
Speaker 1: We did, yes, And it also came up in an
Speaker 1: older episode on mummies. Actually the word the word mummy
Speaker 1: is linked to the word bitumen. Uh. And then of course,
Speaker 1: physicians in the in the region eventually used it to
Speaker 1: treat a number of ailments, but by three thousand b
Speaker 1: c e. It was used in mortar, among other things,
Speaker 1: and by it was used in waterproofing, and it was
Speaker 1: later used in roads along with burnt bricks. And around
Speaker 1: six fifteen BC, King Nebuchadnezzar and his father Nabopolassar mentioned
Speaker 1: it's mentioned its use in streets paved for the procession
Speaker 1: of the great god Marduke. Oh, nothing less for the
Speaker 1: feet of Marduk. Yeah. But then this brings us back
Speaker 1: to the Roman roads, which we've already been touching on,
Speaker 1: because though the Roman roads are generally considered the peak
Speaker 1: of row making in the ancient world, the one shouldn't
Speaker 1: dismiss the roadmaking prowess of say the Persians and the
Speaker 1: Chinese before them. But still this was an empire like
Speaker 1: famous for their roads. We have the saying all roads
Speaker 1: lead to Rome for a reason now is lay points out.
Speaker 1: Rome was, of course an empire, and empires have a
Speaker 1: way of taking certain things, either culturally or technologically, from
Speaker 1: from others, either those who have come before or those
Speaker 1: who are brought into the empire. Right, so they made
Speaker 1: use of Greek lime cement and masonry. Uh, it trust
Speaker 1: can cement, uh, Carthaginian pavement and Egyptian surveying. Uh. They
Speaker 1: famously utilized lime based concrete as early as five hundred
Speaker 1: nine b C. And what's crazy is that after the
Speaker 1: Roman Empire collapsed around four hundred C, concrete construction basically
Speaker 1: disappeared from Europe and it didn't pop up again until
Speaker 1: roughly seventeen fifty four. And that's when a gentleman by
Speaker 1: the name of William Smeaton, founder of civil engineering in England,
Speaker 1: developed a mortar of limestone and clay that hardened underwater.
Speaker 1: All right, so we've we've kind of breezed through the
Speaker 1: history of roads here. Again. Leigh has a whole book
Speaker 1: on this and it's a great read. So I recommend
Speaker 1: anyone check that out if you want to deep or dive.
Speaker 1: But this brings us to the legacy of roads. It's
Speaker 1: really difficult to think about our world without roads in
Speaker 1: them because roads just criss cross everything they can. They
Speaker 1: can truly be seen from space. Even a few Roman
Speaker 1: roads and especially some desert highways, really stand out against
Speaker 1: the surrounding environment. Yeah. Well, I mean It's interesting how
Speaker 1: often um roads and pathways have remained the same for
Speaker 1: so long, or remained close to the same. It's one
Speaker 1: of the bridges between the technological civil infrastructure of the
Speaker 1: ancient world in the modern world. Uh. The way, in
Speaker 1: Europe you still find so many of the Roman roads
Speaker 1: basically in use. And of course one of the things
Speaker 1: about roads remaining in use is that you here have
Speaker 1: to build new roads over the old roads, or you
Speaker 1: have to just maintain the roads. You have essentially continuously
Speaker 1: rebuilding them piece by piece, and kind of a ship
Speaker 1: of theseus uh manner, I suppose, uh And and along
Speaker 1: these lines, um Scott Benjamin who does some some research
Speaker 1: for this show. He u. He pointed us in the
Speaker 1: direction of a Midwest blog post titled how much does
Speaker 1: it cost to build a mile of road? With some
Speaker 1: interesting stats in it. Yeah, this is something I've never
Speaker 1: really considered before because we see road maintenance going on
Speaker 1: all the time, and generally our main reaction is, oh,
Speaker 1: this is annoying, this is slowing me down. So just
Speaker 1: consider these stats. Uh, these these are these are these
Speaker 1: regard building the road, forging a new road. Okay, to
Speaker 1: build a new two lane undivided road in a rural
Speaker 1: area cost between two and three million dollars per mile,
Speaker 1: and in urban areas that's going to go up to
Speaker 1: three and five million, because you're gonna have to deal
Speaker 1: with with because of all the stuff you're gonna have
Speaker 1: to go around, all the infrastructure you're gonna have to
Speaker 1: deal with, et cetera four lane highway, you're talking about
Speaker 1: between four and six million in rural areas and in
Speaker 1: suburban areas between eight and ten million again per mile.
Speaker 1: The US currently has somewhere in the neighborhood of sixty
Speaker 1: one million lane miles, and to to mill and resurface
Speaker 1: a four lane road it costs an average of one
Speaker 1: point twenty five million dollars per mile. And if you're
Speaker 1: looking to do a four to six lane expansion on
Speaker 1: top of that four million dollars. Sounds like we need
Speaker 1: to get into the road business. Well, in a way,
Speaker 1: it's a great, great business to be in, I guess
Speaker 1: because the roads. The roads are everywhere. The roads are
Speaker 1: even the best roads are continually falling apart because they're
Speaker 1: weathered by all of these forces we've discussed, plus the
Speaker 1: intense traffic traveling atop it we're going to keep needing them, Yeah,
Speaker 1: and we also keep coming up with new twists on
Speaker 1: the concept. Now, one of my favorite concepts of regarding
Speaker 1: the future of roads is UH is certainly a lofty one,
Speaker 1: but one that is attractive in many ways. UH. And
Speaker 1: it is the idea of an underground automated highway or
Speaker 1: you a h like a subway. Essentially, it's like, the
Speaker 1: idea is, we've we've kind of corrupted the world. We've
Speaker 1: divided up this the natural world with all of these roads,
Speaker 1: and anytime animals try and cross it, they die, and
Speaker 1: it's breaking up for us, et cetera. But what if
Speaker 1: we were able to put all of those roads underground
Speaker 1: or in some cases, you know, build some sort of
Speaker 1: green structure over it, and the animals could crawl over that,
Speaker 1: the vegetation could grow a top of it, and they
Speaker 1: would have all they would be all of these uh
Speaker 1: environmental benefits as well. What if we had this kind
Speaker 1: of world and then on top of that that, you know,
Speaker 1: the cars are going to drive themselves as well. So
Speaker 1: imagine like those wildlife bridges, but it's not a bridge,
Speaker 1: it covers the entire road exactly. Yeah. Just what if
Speaker 1: we just had nothing but wildlife bridges, and it just
Speaker 1: kind of concept. And there have been some lovely, uh
Speaker 1: you know, illustrations depicting what this kind of world would
Speaker 1: look like and and that they do kind of line
Speaker 1: up with a lot of these, you know, very ambitious
Speaker 1: and optimistic visions for what the future of say, you know,
Speaker 1: certainly like Middle America I guess would look like. I mean,
Speaker 1: you could also certainly put the roads underneath the cities,
Speaker 1: like everything becomes the subway in an urban environment. Um,
Speaker 1: I don't know. I haven't looked recently to see what
Speaker 1: even the most optimistic time frame is for this sort
Speaker 1: of thing, but it's it's a lovely technological dream if
Speaker 1: nothing else. Oh yeah, I mean to imagine cities where
Speaker 1: all of the surface spaces for pedestrians or is green space. Yeah, like,
Speaker 1: it's not even for pedestrian humans, it's for pedestrian deer
Speaker 1: and and mega fun let's bring them back to and
Speaker 1: released crocodiles. No, seriously, I do like that, but until
Speaker 1: we get to that point, we are stuck with the
Speaker 1: roads we have, which are pretty impressive technological feats. Yeah.
Speaker 1: All right, So that's it for this week's episode. Of Invention.
Speaker 1: If you want to learn more about the show and
Speaker 1: check out other episodes, head on over to our website
Speaker 1: invention pod dot m. Big thanks to Scott Benjamin for
Speaker 1: research assistance with this episode, thanks to our audio producer
Speaker 1: Torii Harrison. If you would like to get in touch
Speaker 1: with us directly with feedback on this episode or any other,
Speaker 1: to suggest a topic for the future, or just to
Speaker 1: say hi, let us know how you found out about
Speaker 1: the show where you listen from all that kind of stuff,
Speaker 1: you can email us at contact at invention pod dot com.