Next month marks the 50th anniversary of the creation of the National Historic Preservation Act (NHPA). This act, along with other regulations passed from the mid-1960s to the early 1970s, helped end an era of large-scale, federally funded construction projects that followed World War II. A new book by Francesca Russello Ammon examines this period of unbridled demolition and construction through the lens of the machine that came to symbolize it—the bulldozer. In Bulldozer: Demolition and Clearance of the Postwar Landscape (Yale University Press), Ammon explains how the dozer transformed from a heroic weapon in the “arsenal of democracy” into a tool for urban planning, suburban development, and the creation of the interstate highway system.

A Dirt-Moving War

Yale University Press/reprinted with permission from the Wisconsin Historical Society

The Allies deployed more than 100,000 tractors during World War II. Earth-moving equipment manufacturers like Caterpillar, International Harvester, Allis-Chalmers, and LeTourneau provided the mechanical muscle behind the land-clearing and construction efforts of Army Corps of Engineers in Europe and the Naval Construction Battalions (NCBs) or Seabees in the Pacific. In this photograph from 1944, International Harvester TD-9 crawler tractors equipped with bulldozer blades and front-end loaders are lined up in large groups in preparation to be shipped to various Pacific battle zones.

Conseil Régional de Basse-Normandie / National Archives USA

“Victory seems to favor the side with the greater ability to move dirt,” Major General Eugene Reybold, the head of Army Corps of Engineers, declared in 1944. The Army Corps used the bulldozer on the front lines in Europe to crush barriers to forward advancement. Here, a Caterpillar D7 with angle-dozer equipment and a LeTourneau CK7 blade fills bomb craters on a road in Normandy west of Saint-Lô as soldiers from a stalled convoy look on.

Conseil Régional de Basse-Normandie / National Archives USA

General Reybold further stated, “By the war's end, it was evident that American construction capacity was the one factor of American strength which our enemies consistently underestimated ... the one for which they had no basis for comparison. They had seen nothing like it." In this photograph from 1944, two US Caterpillar D7s clear the bombed-out streets of Saint-Lô, France. The Army Corps would go on to use the bulldozer to help remove some 183 million cubic yards of stone and rubble in Berlin, Hamburg, Cologne, and Dresden alone after the war.

Yale University Press/US NCB; 4th (Baton Rouge: Army and Navy Pictorial Publishers; 1945)

In the Pacific, the Seabees cleared enough jungle with bulldozers to build more than 400 bases, 100 air strips, 235,000 roads, 700 acres of warehouses, housing for 1.5 million men, and storage tanks for 100 million gallons of gasoline as the Navy and Marines island-hopped towards Tokyo.

U.S. Navy Seabee Museum; Collections Department; Port Hueneme; CA

The Seabees were formed shortly after Pearl Harbor, in large part because Navy leaders worried civilian crews would not function in a tight cohesive unit under fire. Also, as civilians, work crews would be legally prohibited from engaging in combat for fear of capture and being treated as guerrillas (rather than as military prisoners of war) and thereby risk being summarily executed. It was the first time the U.S. military had absorbed construction industry personnel wholesale, rather than developing its own engineering crews. As the war progressed, their ranks grew to a wartime peak of more than 250,000 men with the majority deployed in the Pacific. Here, Seabees load a dozer onto a lowboy trailer in Guadalcanal (February 1945).

U.S. Navy Seabee Museum; Collections Department; Port Hueneme; CA

Ammon notes, "Tractors derived value not only from the power of their engines but also from the versatility of their attachments. Typical attachments included bulldozer blades for pushing, winches for towing, hoists for lifting, and scrapers for hauling large amounts of earth." In this photo, a Seabee uses a Cat D7 with a LeTourneau scraper to create an airstrip in the Pacific Theatre. During the war, R.G. LeTourneau, Inc. would develop a symbiotic relationship with Caterpillar (the conflict’s largest tractor producer) developing bulldozer blades and scrapers. All told, LeTourneau supplied 70 percent of all the ancillary heavy earthmoving equipment used by the Allied forces during World War II.

Marketing the Bulldozer (During and After the War)

Allis-Chalmers heavy equipment plant (1945); copyright Sangamon County Historical Society

Despite heavy demand for earthmoving equipment during the war, manufacturers reaped only modest financial rewards (at best). Often, American companies that engaged primarily in war work saw their profit margins decline due in part to government-set price levels and the passage of a war-time excess profits tax to prevent them from engaging in war profiteering. Ammon notes, "Instead of near-term profits, however, manufacturers relied on less tangible, long-term rewards in the form of technological advancement, the training of laborers, and an enhanced popular depiction of the value of their brands and the work of their machines. In the post-war period, they would put these less tangible benefits to productive use when they returned to peacetime operations."

Allis-Chalmers “One Man Task Force” ad; copyright Sangamon County Historical Society

Manufacturers invested in product and brand marketing during the war itself to help ensure those future financial rewards. They built marketing campaigns around their contributions to the war and preparedness for its aftermath by portraying American construction equipment as durable, powerful, and patriotic technology. Here, the ad copy from this Allis-Chalmers ad reads:

“Tractor Bulldozers mount no guns, are not even armored. Yet men who put service above self are taking them into the danger zones to clear the path ahead of the guns. Many a Mother’s son is living tonight because a bulldozer driver did not falter in the performance of his mission.

If you could sit at the elbow of a ‘dozer operator when he opens the throttle of his crawling powerhouse, you would see first-hand how it’s done. How, for instance, Seabees in the Aleutians built a bomber airfield by pushing a mountain into the sea. How they built a runway in the Solomons despite touching off a buried 100 lb. Jap bomb that twisted one corner of the rugged bulldozer blade, but failed to stop the tractor.

In the thick of one attack, there were six casualties in succession at the controls of a single tractor, yet the seventh man took over determined to keep it rolling. Courage like that is not a thing that can be described.

We of Allis-Chalmers are proud of these men who operate the tractors we build. Our hat’s off to Uncle Sam’s one-man task force, the bulldozer driver. And our sleeves are rolled up in sincere effort to live up to his example.”

Yale University Press/reprinted with permission of Granite Fluid Power; Granite Falls; MN

This 1944 ad for hydraulic tractor equipment, published in Military Engineer magazine, foretells of a world of opportunity for postwar earthmoving work.

A Culture of Clearance

Yale University Press/reprinted with permission from the Edgar Browning Collection

Earth-clearing skills honed overseas were put to use when these land-altering machines and their highly trained operators returned home “to wage war on the American landscape.” Urban planners made a correlation between blighted American cities and bomb-damaged European ones, recommending clearance and rebuilding for both. The Housing Act of 1949 provided for two-thirds of the cost of clearing land and making possible the assemblage and write-down of large urban parcels to attract privately financed new development. In this 1952 photo, a bulldozer operator removes demolition debris to make way for the Cross Bronx Expressway, part of a massive development scheme for New York City.

Reprinted with permission from Tennessee Department of Transportation

Upon seeing the efficiency of Germany’s autobahns, former Supreme Allied Commander, Dwight Eisenhower, decided as president to “to put an emphasis on this kind of road building” and pushed for the Federal-Aid Highway Act. The bill passed in 1956, authorizing a 41,000-mile, 10-year building program—with 90% of construction costs paid for by Uncle Sam. Here, road builders queue up to work on a section of interstate in rural Tennessee (1960).

Yale University Press/ Photo courtesy Oranges County Archives

When Seabees like Bill Levitt (the builder behind New York’s Levittown) and Hugh Codding (the creator of “Coddington”—the first covered shopping mall in Sonoma County, Calif.) came home, they brought their new and refined skills with them. Levitt would go on to built 17,000 homes, constructed en masse, on more than 1,000 acres of former potato fields in Long Island, N.Y., while Codding drew upon the "speed building experience" he had gained in the war, to give his building activities a promotional flare. For a 1950s publicity stunt, his crew assembled an entire house in just over three hours. Codding's projects helped transform the landscape of postwar Sonoma County from orchards into suburbs.

In Orange County, Calif., the complete land-clearance process (including tree uprooting, refuse removal, and land grading-typically) cost developers about a dollar per orange tree, or roughly a hundred dollars per acre. This was a tiny part of the total development costs, making the destruction of orchards an economical and consequently, almost forgettable step in the home-building process. In this photo, California mechanic Weldon Field uses a tractor-mounted stump puller he developed to uproot an orange tree.

Yale University Press/

This 1946 aerial photo, coupled with the following 1972 photo of Santa Ana Canyon, illustrates the evolution of suburban clearance that took place and leveled previously undeveloped hillsides in Orange County, Calif.

Yale University Press/

According to Ammon, "Changes in the postwar tax code encouraged the growth of suburban development. In 1954, the IRS introduced accelerated depreciation, reducing the length of time necessary to write down a building from forty years to seven. This accounting change stimulated further land clearance by making it more profitable to build new construction on green-field sites than to reuse existing locations." And, when orchard flatlands ran out (shown in the upper and lower portions of the photo), large homebuilders began to target new hillside construction (middle of photo). She notes, "By the late 1960s and early 1970s, builders were leveling the hilltops for denser, more uniform development in a process dubbed "mountain cropping." Their environmental modifications were more extreme: instead of adapting homes for the topography, they scraped away the mountains to create vast flat pads to accommodate the repetitive building tracts characteristic of low-lying, level lands."

Bulldozer: Demolition and Clearance of the Postwar Landscape (Yale University Press)

All told, 7.5 million dwelling units were torn down from 1950 to 1980 largely in the name of urban renewal and highway planning, and 42 billion cubic yards of earth were moved to create the interstate system. The excavations displaced a vast number of people—hence the bulldozer became a symbol of protest as angry citizens began to push back against what Ammon calls “a culture of clearance.”