Roads, highways, and ecosystems

From The Encyclopedia of Earth
Jump to: navigation, search
Indiana Dunes National Lakeshore, Indiana. Fragmentation of park land by urban areas, such this highway, can create islands of natural ecosystems and can disrupt the natural movement of plants and animals. (By Esculapio Domain, via Wikimedia Commons)
Environmental History (main)

Lead Author: John Stilgoe (other articles)

Content Partners: National Humanities Center (other articles) and TeacherServe (other articles)
Article Topics: Transportation
This article has been reviewed and approved by the following Topic Editor: Brian Black (other articles)

EDITOR'S NOTE: This entry was originally published as "Roads, Highways and Ecosystems" in the series "Nature Transformed: The Environment in American History," developed by the National Humanities Center and TeacherServe. Citations should be based on the original essay.

New Ulm, Minnesota, 1974. (Source: U.S. National Archives)

In the United States, formal education begins on the road, often along the city street. Nowadays for the bulkof students away from downtown urban America, it begins aboard the yellow school bus collecting children bound for the first day of kindergarten. Before most children encounter principals and teachers, they meet the driver of the school bus. The driver enforces rules—no hanging out windows, jumping over seats, throwing things. Inside the school bus the six-year-olds find a new sort of teaching perhaps, certainly a new authority very unlike parents.

Who really thinks about school-bus culture? Older children sit in the middle of the bus, and the oldest kids take over the far rear. Girls separate from boys, some kids read, others stare from windows and never talk, some merge with headphones. Why do the older kids sit in the back, away from the driver? Why do school buses lack seatbelts? When high school students turn sixteen and begin learning to drive, they need all the tutoring they can get, so why do they not start early and watch a specialist driver maneuver a very long vehicle indeed, one that moves so well protected by laws and public care that it needs no seatbelts, at least for its passengers? Across most of the United States, the immense school bus fleet makes possible the school systems Americans take for granted. Large elementary schools and consolidated high schools depend on the busing of students, but few scholars examine the importance of the school bus and the road it travels.

Missouri, 1909. (Source: Library of Congress)

Until about 1900, most American school children walked to school. In some cities, they walked along paved sidewalks, but since the bulk of the population still lived on farms and in very small towns, mostly they walked along dirt roads to one-room schoolhouses sited to be equidistant from farms and small-town homes. People walk about four miles an hour, and few school districts expected children to walk more than an hour to school and another hour home. Sometimes school boards hired farmers to drive passenger wagons called school barges to bring the more distant children to school, but more often they merely located another one-room schoolhouse within walking distance, expecting the teacher to board with a nearby family. Attending high school in 1900 meant being lucky enough to live within walking distance of one, say in a city, or having parents willing to pay the room-and-board costs that allowed a student to live with another family near a high school. Many children quit school around eighth grade simply because they could not get to high school. Advanced education is the chief environmental impact of good roads and motor vehicles, if environment means the entire surroundings in which we live.

New York City, 1900, with only two motor cars amidst the horse-drawn traffic. (Source: U.S. National Archives)

At first only the very rich used automobiles. The term horseless carriage rewards scrutiny, for most American used buggies or wagons, not carriages. In 1895 only about three hundred motor vehicles operated more or less regularly on United States roads, and most stayed on stone-paved city streets. At the New York automobile show in 1900, a full third of the cars had battery-powered electric motors, and almost all the rest moved under steam. In that year between six and seven thousand automobiles moved along urban American streets, but the brief era of technical experimentation had ended. Automobiles had become reliable and dramatically less expensive. Five years later a number of bicycle manufacturers and, of course, Henry Ford, had developed a burgeoning industry: in 1905, 77,988 automobiles and other self-propelled vehicles had been registered with state governments. The manufacture of automobiles developed after 1905 the way the manufacture of personal computers developed in the mid 1980s. A whole new industry appeared almost by magic, and suddenly every family wanted an automobile. By 1925, seventeen million automobiles were registered in the United States.

But bad roads stymied the growth of the industry and infuriated early motorists.

Florida, ca. 1890. (Source: Florida State Archives)

At the beginning of the twentieth century roads had become obsolete for anything but short-distance travel. The era of the stage coach and country inn was long over except in the most remote rural regions. Railroad companies had put down track to almost every American village, and fierce intercity competition between companies caused long-distance passenger train service to be reliable, comfortable, and very fast, with many passenger trains hitting eighty or ninety miles an hour for short stretches. Americans used roads to get around neighborhoods and to reach the nearest railroad station, where they expected a smooth-riding, on-time train. In a sparsely populated nation, especially west of the Mississippi River, a county might have only several hundred families but have several hundred miles of dirt roads to maintain. Farmers intermittently dragged a log along the roads to smooth out bumps and holes, but most Americans put up with wretched conditions because they were not going very far and because they refused to pay to improve the roads for strangers who were. Sensible people used railroads.

Sentinel Butte, North Dakota, 1915. (Source: Library of Congress)

The first group to agitate for better roads, the League of American Wheelmen (LAW), grew out of the 1890s bicycle craze, and the second group evolved with railroad company support. Bicyclists adored paved roads, but away from cities found none. By 1900 the LAW had become the nation's largest special-interest group, and it advocated paving roads with crushed stones. The macadamized road, named after its Scottish inventor, John Loudon MacAdam, had a multilayered surface of crushed stone: the largest stones, about the size of an adult human skull, at the bottom, then another layer about the size of an adult fist, then a top layer of stones no larger than can go into an adult mouth.

Prison inmates, 1928. (Source: Florida State Archives)

Macadamizing a country road meant backbreaking work in the days of horses, wagons, and picks and shovels, and until the development of steam-powered stone crushers, many states set convicts to work smashing stones with sledgehammers. Convict labor sometimes moved outside prisons to the roads themselves, the men working under guard, and sometimes in the chains and manacles that led to the expression chain gang.

Isaac B. Potter, The Gospel of Good Roads: A Letter to the American Farmer, 1891, title page.

While no one proved much about the economics of convict labor, the LAW insisted that the macadamized roads benefited more people than just the bicyclists. Gradually, the LAW convinced farmers that a road fit for bicycles saved farmers time, trouble, and money. Between 1889 and 1900 it distributed about five million copies of its pamphlets on road improvement. The most famous of the pamphlets, The Gospel of Good Roads: A Letter to the American Farmer, appeared in 1891, and convinced many farmers that improved roads meant reduced transportation costs (fewer horses hauled the same tonnage), much time saved in traveling back and forth to town and to neighbors', and far fewer damaged wagons and lamed horses. The LAW joined forces with farmers in a new lobbying group, the National League for Good Roads, and the new group soon convinced railroad companies to join.

"Good Roads" trains, 1910. (Source: Minnesota Historical Society)

Railroad companies quickly accepted the National League arguments and began sending "Good Roads" trains to rural stations. At railroad company expense, men and machinery would build a mile or two of macadamized road away from a railroad station into the country. Horse-drawn dump wagons and graders, but above all, a steam roller for packing down the stones, impressed onlookers from the beginning.

But the new surfaced roads stunned everyone. Farmers instantly realized that on a macadamized road their horses worked far less hard, and that indeed a two-horse team could pull a wagon needing a four- or six-horse team on ordinary dirt roads. A macadamized road drained well on rainy days and never turned to mud, and the steel wagon-wheel rims and steel shoes of the horses compacted the top layer of small stones into a hard, more or less even surface that stayed in place wonderfully well. Farmers living along a macadamized road became more efficient and increased crop production, which meant more produce for the railroad companies to haul from rural stations to cities. However unlikely the combination seemed at first, the LAW and the railroad industry soon convinced the nation's farmers that macadamized roads increased productivity and cut transportation costs. Once used to the roads, farmers and other rural and small-town short-distance travelers suddenly disliked dirt roads as utterly old fashioned.

Henry Wallace, "How to Make Good Dirt Roads," 1905.

Where farmers could not afford macadamized roads, they began to drag them with crude devices made from split trees. Invented around 1904 by a Missouri farmer, D. Ward King, "the King road drag" was soon used by farmers everywhere in the United States to improve roads. Farmers working outside the Iowa town of Owasa even had a song to speed their work with the drag:

Dragging the roads, dragging the roads
Dragging the roads with the King road drag;
Hard as a bone, smooth as a hone,
The roads that lead into Owasa.

In many parts of the nation, the simple King road drag improved roads enough that farmers found macadamizing unnecessary.

Then, suddenly, technological change fractured the alliance of bicyclists, railroad companies, and farmers. Motor cars not only ruined macadamized roads but destroyed drag-smoothed roads too. Automobile tires ripped up the compacted surface of steam-rolled stones, making ruts that annoyed bicyclists and horse-driving farmers alike. The ruts channeled rainstorm water that eroded roads or trapped it in dangerous puddles that in winter froze into road-heaving chaos. But once automobiles operated reliably and at speeds up to fifteen miles an hour, town-to-town travel became possible over macadamized roads. By 1915 railroad companies noticed dramatic decreases in short-distance passenger ridership as more and more people abandoned buggies—and bicycles—for automobiles. An extraordinary transportation revolution was under way, and no one had a clear picture of what would happen even five years ahead.

Putting in street pavement at Kerkhoven, Minnesota, 1925. (Source: Charles Lincoln Merryman, Minnesota Historical Society)

But by 1925, seventeen million automobiles and other motor vehicles operated over twenty thousand miles of concrete-paved roads and over hundreds of thousands of miles of improved roads.

What does improved roads mean? Not every improved road had a concrete surface, and the newer, and perhaps cheaper, petroleum surface called asphalt. Many improved roads were paved with crushed stone, and many others were graveled. But almost all were raised, ditched, and graded.

Road paving, 1920. (Source: Minnesota Historical Society)

Raised roads. A road raised above the abutting land is technically a highway. Such roads existed in antiquity, and indeed the Roman empire depended on a network of paved roads elevated above adjacent ground. Only main roads crucial to an empire or kingdom stood proud, elevated a foot or so above the natural topography. Such roads, incredibly expensive to build and maintain, carried special legal status. Knights and sheriffs policed them at the behest of emperors and kings, and even today the phrase highway robbery endures to mark a sort of robbery that insults a king. A medieval peasant robbed on an ordinary road demanded justice, certainly, but a peasant robbed on the king’s highway knew that the bandit had insulted the royal offer of protection to all travelers and that his crime would mean the arrival of sheriffs and even troops if necessary. And too, any king knew that having highways meant having to honor the promise of royal protection not only against bandits but against mud holes and washouts.

Elevating a road meant simply that it drained during and after rain, that it did not turn to mud. Travelers expected a highway to be free of mud, and free of ruts too, and they expected the well-drained road surface to stay smooth during cold weather, to remain free of frost heaves. The American colonists knew few such roads, although here and there a long-distance road might be called a royal highway. After independence the Constitutional Convention, fearing the tyranny implicit in any national government capable of building highways and knowing the horrendous difficulty of building and maintaining roads in a vast, still half-settled land, expressly forbade Congress from building highways. Well into the nineteenth century, as Andrew Jackson and other presidents struggled with legal problems involving the National Road, and as turnpike companies built and maintained private toll roads, Congress, the Supreme Court, and state governments argued about the legal intricacies of building highways. But after the 1840s, interest waned. The railroad industry solved the road problem.

Tip over, 1915. (Source: Emil King, Minnesota Historical Society)

In the first years of the twentieth century all the old legal questions resurfaced from the past, as motorists demanded better and better roads, especially highways elevated above surrounding land. Early automobiles rode high on their wheels, in part to protect undercarriages from being struck by rocks, in part to keep wheel hubs out of the mud. High-riding automobiles tended to tip over easily, however, and soon motorists and manufacturers alike demanded smoother roads so that cars might ride closer to the ground. Who accepted responsibility for accidents caused by poor-quality roads? The motorist? The county government? No one? At the beginning of the twenty-first century, American motorists often favor large, high-riding, four-wheel-drive sport utility vehicles out of the thinking that originated in 1910. Better to drive above the rock or through the mud now than damage the car and sue later, they reason, in a way that Henry Ford would have understood.

Slowly, reaching out from cities into suburbs, and from large farm towns into rural regions, reached the first elevated roads, the first highways on which motorists could expect a fairly well-drained surface. Elsewhere, if they were lucky, motorists found ordinary gravel roads and even dirt roads improved only by ditches.

Road ditch, 1929. (Source: Minnesota Historical Society)

Ditches. Ditches help roads to drain, even when roads are not elevated much, if at all, above abutting land, but even in pre-Civil War turnpike days, ditches presented serious problems. In heavy [[rain]s], ditches fill, then flood, and sometimes turn into miniature rivers whose currents erode roads. Always they represent a danger to anyone, teamster or motorist, veering away from the center of the road. In the early years of automobiling, motorists whose brakes failed sometimes deliberately steered into ditches rather than collide with livestock or other vehicles. To ditch meant the deliberate wrecking of a car in order to stop it, and eventually the word carried over into airplane slang: today pilots still ditch planes, especially in the ocean. To be ditched, however, meant being run into a ditch by another motorist, and the phrase carried over into much early twentieth-century slang, especially that involving love affairs. Either way, by intent or by accident, to be ditched meant finding oneself and one’s vehicle in a foot or so of mud and stagnant water. Bruises and broken axles usually accompanied ditching or being ditched, and prudent motorists tried to remain in the center of ordinary roads rather than risk swerves caused by blowouts. Any swerve meant the possibility of ditching.

Grader pulled by tractor, 1910. (Source: Minnesota Historical Society)

Graded roads. The middle of many highways and roads stood slightly higher than the edges, for road grading machines sculpted road surfaces into slight arches, called crowns. At first horse-drawn, then propelled by gasoline and diesel engines, road graders shaped the pitch of roads to speed the runoff of [[rain]fall] and to smooth out bumps and fill holes. After the road grader passed, the cross-section of a road showed a slight arch, but many motorists noted that a hard rain often destroyed the gentle arch and reduced the road to mud and ruts overnight. So in county after county, small town after small town, operating the road grader became a permanent occupation. Five or six days a week, somewhere in a county or a municipality the roadgrader worked, its work never, ever done, especially after summer thunderstorms, spring freshets, and the frost heaves of deep winter.

If elevated, ditched, and graded, a macadamized highway might allow speeds of twenty miles an hour, and by the 1920s struck many motorists as a high-speed ribbon tying together two cities or perhaps a small town with another. When paved with concrete or eventually asphalt, it permitted even higher speeds, and automobile manufacturers produced ever faster cars intended to compete with long-distance railroad trains. The new model cars sat far lower to the ground and did not tip over when they swerved at full speed. Better roads led the Ford Motor Company to replace its early, high-riding Model T with the Model A, a far safer automobile, but one that depended on high-quality road surfaces.

By the late 1930s, when the low-pressure tire replaced the high-pressure ones so likely to blow out, the expression going like sixty entered American vernacular English as meaning going so fast that control began to lessen and lessen. In 1941, when the Pennsylvania Turnpike opened as one of the first limited-access divided highways that presaged the post-World War II interstate highway system, motorists discovered it lacked any speed limit at all. Along some stretches the average speed hit ninety miles an hour, and half-wondering, half-terrified motorists gripped their steering wheels and marveled at speeds undreamed of twenty years earlier. Once the United States entered the war, gasoline shortages reduced speeds dramatically, but long after the federal government built the Military and Interstate Highway System—to use its real name, which designates it as a weapon and so able to be built by a Congress forbidden by the Constitution to build highways—American motorists remembered the thrilling years of going far faster than sixty.

Florida Highway 25 under construction Miami, 1960. (Source: Florida State Archives)

Any road rewards sustained scrutiny. Roads are so taken for granted that very few Americans look at them closely. But an accurate look reveals the crown so carefully engineered into the asphalt pavement, the complex system of storm drains—and ditches—that carries away rain water, the super-elevated curves that carry automobiles around bends at high speed, the wide shoulders that let motorists pull off pavement without driving immediately into ditches, all the details in which highway engineers take such well-deserved pride.

Colorado. (Source: U.S. National Archives)

But look again. Every road is a sort of ecosystem that ecologists are only just now starting to study. Non-porous pavement causes [[rain]fall] to collect at its edges, if only momentarily. So along most roads across much of the western United States, say west of the 98th meridian of longitude, the edge of the pavement is bordered by a ribbon of plants that need slightly more annual rainfall than do the plants only three or four feet away. Quite often the ribbon plants are taller and greener than ones growing a few feet distant, and the plants shelter wild animals waiting to cross what they sense, correctly, is a barrier. For reptiles, especially at night in cool weather, the blacktop is a warm place to rest, and often a fatal one. For many mammals, it is a zone to be crossed at speed, but not only because vehicles present a threat: the road offers nowhere to hide from hawks and other raptors. But predatory birds, and carrion feeders too, risk annihilation, for they are easily struck by vehicles, especially at dusk when headlights blind and disorient them. Yet for all that the road is a barrier, its edges are also animal highways. This last is incredibly important, but still very little understood.

Consider the typical interstate highway interchange. What lives at the center of the circular zones wholly surrounded by highways and on- and off-ramps? Sometimes essentially grass, routinely mowed. But sometimes all sorts of vegetation and the animals that hide in the wetlands and woods so close to roads pedestrians never cross.

Or think about the shoulders of interstate highways. What sorts of animals move parallel to the pavement? Are they safe from some sorts of predators? Do they use the shoulders only as routes or do they live between fence and pavement, in a ribbon of half-cared-for vegetation never walked by humans and indeed almost invisible to humans driving at high speed? A traffic tie-up proves useful to the thoughtful, well-educated motorist who looks acutely at the edge of the highway, a strip that is like the margin on the page of a book. It is the edge neither of typeset words nor paper. It is truly a twentieth-century and twenty-first-century ecosystem.

Pacific Highway, Oregon, 1973. (Source: U.S. National Archives)

Moreover, it is a prototype of other ecosystems, especially business ones. Paved roads transformed American towns and cities by allowing businesses to spread along the automobile traffic. Just as the pavement increases [[rain]fall] runoff and enables certain plants to prosper along it, so traffic causes businesses to prosper along all but limited access highways. Put up a building and a sign, and some motorists will pull off the public pavement into the private parking lot, get out, and buy. Railroads concentrate businesses, for passenger trains stop only at specific locations. Highways cause business to spread out, to move to suburbs, to the edge of town, to form commercial strips dependent on motorists pulling to the edge of the pavement—just as rainfall runoff does.

Who studies roads as mini-environments? Very few scholars do, in fact almost none. Highway engineers know a great deal about engineering roads but admit to knowing little about their ecological and cultural effects.

Think about snow and, especially, ice. In 1905 travelers knew that horses pulled sleighs more easily across packed-down snow, and counties and municipalities used great snowrollers to pack down snow. But motorists hated packed snow. It turned easily to ice, and ice meant collisions and spinouts, or no movement at all. For a decade, sleighdrivers and motorists argued bitterly until the motorists won, and local governments began plowing snow from main roads, then from side roads too. Until the 1950s, motorists carried snow chains in their trunks, and expected to stop on the side of the road and fasten them around rear tires when snow began or when they encountered a badly plowed road. The chains mandated very slow speeds, but they proved wonderfully useful on snow and ice both, although they could not be used on dry pavement without tearing themselves to pieces. But putting them on and taking them off involved so much time and effort that states began sanding and then salting roads. Sand improved traction a bit, and rock salt melted the snow and ice completely. Not until the early 1980s did anyone realize that the saltwater runoff polluted not only shallow wells near roads but entire groundwater supplies. How does society measure the pluses and minuses of keeping roads open in snowstorms and icestorms? Across much of the South, where snow and ice are rare, states still let nature take its course and assume that within a day the roads will be passable. But in the North and in the Rocky Mountains, snow and ice removal usually involves salt-spreading, and no one can predict the long-term environmental results.

Salting city streets, 1940. (Source: Minnesota Historical Society)

Snow and ice are part of the larger natural-systems puzzle open to anyone who thinks carefully about almost any road in the United States away from the southernmost regions and Hawaii. Look closely at the back of the cab of any long-distance eighteen-wheel truck: almost always snow chains swing from hooks. The trucking industry understands how much traction the chains provide, but the typical motorist now relies on all-weather tires pretty much useless in ice or heavy snow. The snowstorm or ice storm that closes airports and grounds airliners, that closes interstate highways even to trucks equipped with chains, rarely interferes much with railroad operations. Even in the foulest of weather, passengers expect Amtrak to operate on time. Perhaps, just perhaps, the effects of snow and ice on twenty-first-century roads suggest that something better exists, the railroad so efficient in 1895, the railroad so efficient today.

Bad weather cancels school. Students learn during snowstorms and teachers teach during sleet, everyone snug inside warm, well-lit schools. But school superintendents and local highway authorities always worry about the safety of the school buses that bring students to school and get them home. Heavily falling snow or poorly plowed roads, even a quarter-inch thickness of ice after sleet and freezing rain mean the buses cannot operate safely, and authorities declare “no school” or decide to close school early. Whatever else it teaches, the combination of school bus and road teaches the complexities of highway transportation and natural ecosystems. Nothing better rewards an educated mind than a few minutes of observation of one’s surroundings, say the road along which the school bus will come in a few minutes. On that road depends United States public education as it exists today.

Highways across the continent of North America. Source: Saikat Basu, own work


Center, N., , T., & Stilgoe, J. (2014). Roads, highways, and ecosystems. Retrieved from,_highways,_and_ecosystems