The development of road systems in national parks involved interrelated political and economic issues. Although based in the idealism of the Organic Act that established the National Park Service, park development relied on appropriations that were linked to visitation. During the late 'teens and 'twenties the National Park Service pushed for funding for the construction of park roads, urged the development of access roads to national parks, and supported the road network known as the National Park-to-Park Highway. When Robert B. Marshall was detailed temporarily from his position as chief geographer of the U.S. Geological Survey to the general superintendent of the national parks in 1916, he wrote of three functions of national parks: stimulating national patriotism; furthering knowledge and health; and diverting tourist travel to scenic areas of the United States.  Later annual reports of the director of the National Park Service and other documents for that time period showed clear motivation. Although many records chronicled the scenic and inspirational qualities of national parks, a recurrent theme throughout the literature involved increasing the economic strength of the nation through tourism, thereby providing a practical justification for parks. Allowing automobile access to national parks was the answer.
At the same time that these efforts were underway, the number of automobiles in the United States increased dramatically from 8,000 in 1900 to 23 million in 1930.  This prompted a major change in how parks operated. Initially most visitors had arrived at parks via train. The railroads made most of their park-related money from the sale of passenger tickets, and they made very little if any from concessions operations. with which they were connected within park boundaries. Thus, their greatest profits came from outside the parks. Following the dramatic increase in autotourism by the 1930s, as environmental historian Alfred Runte pointed out, the profit-taking from visitors' pockets shifted from outside park boundaries to inside the boundaries as visitors spent money on hotel accommodations, meals, and souvenirs. 
Coincident with the early physical development of national parks was the evolution of a design ethic that emphasized an organic approach to architecture and landscape. This evolution, the roots of which lay in the 19th century work of horticulturist Andrew Jackson Downing and Landscape Architect Frederick Law Olmsted, stressed design in harmony with nature. Following this ethic, nature was the most important element of design, and all design decisions subordinated the built environment to the natural environmental. National Park Service (NPS) designers during the 1920s tended to perceive roads and buildings as necessary evils, and they incorporated a variety of means in their designs to achieve harmony with the surrounding environment. The use of onsite, natural materials, sensitive siting that responded to nature, and curvilinear road alignments that hugged the topography were characteristic of this type of rustic design. Because this ethic permeated all aspects of park design, national parks began to develop a distinctive, identifiable look and feeling.
The creation of a formal partnership between the National Park Service and the Bureau of Public Roads in 1926 clarified an ongoing alliance. Since 1914 the two agencies had been working hand-in-hand to construct new roads and rehabilitate existing roads in national parks. The interbureau agreement signed by the two agencies in 1926 specified that the Bureau of Public Roads was responsible for surveying, engineering, and overseeing construction of park roads while the Park Service maintained absolute control over the aesthetic and management issues of road design and construction. The roads constructed through this working arrangement included some of the best examples of road engineering and the most scenic roads in the United States.
Thus the Park Service in conjunction with the Bureau of Public Roads built park roads, and the states, often in concert with the Bureau of Public Roads built access and connecting roads. A problem, however, arose. Park roads were so well-designed that the experience of driving a park road became an integral part of the park experience. Sometimes the road became a destination in itself. Driving park roads evolved into one of the recreational experiences that visitors relished in parks. Few visitors went to Sequoia/Kings Canyon by automobile without driving the General's Highway, or to Glacier without driving over Going-to-the-Sun Road, or to Rocky Mountain National Park without driving Trail Ridge Road. Sometimes specific features on the park road also became signatures of the park experience. The carved entrance sign of the profile of the Cherokee leader Sequoyah along the road at the entrance to Sequoia National Park was one of those identifiable marks. The rustic log entrance station at the northeast entrance to Yellowstone was another. Distinctive landscapes or specific vistas developed into indelible images that became part of the collective scenic and cultural heritage of the nation. The view of the mountains and the river from the Snake River overlook at Grand Teton National Park was one of these. All of these elements were part of the park experience that visitors mentally collected and took home with them.
The application of the rustic aesthetic to road design enhanced the park experience so much that more and more visitors came pouring in. The well-designed roads made access easy and something else to write home about. They introduced the American public to the wonders of nature. Yet as early as the 1930s a few faint voices complained of the impacts of road construction on national parks and the number of automobiles and people that the new roads encouraged. Despite these early warnings, NPS administrations continued to foster park development to stimulate tourism for one principal reason congressional appropriations for parks were directly correlated with park visitation figures.
Visitation steadily increased in national parks through the 1930s, and more automobiles passed over park roads. A depressed domestic economy during and after World War II and the Korean War reduced funding for park maintenance, so the roads fell into disrepair. Compounding that situation was the rugged terrain over which some park roads passed. Despite the best engineering available at the time, the forces of nature sometimes overtook the forces of development. Portions of roads collapsed or slumped due solely to the natural conditions under which they were constructed. An influx of funding for road projects during Mission 66 a 10-year development program to upgrade park facilities for the 50th anniversary of the agency altered the manner in which the National Park Service constructed roads. Rather than emphasizing the aesthetics of nature in the design, the matter of greatest concern most often became one of engineering the road to accommodate greater numbers of larger vehicles at higher speeds. Also, highway safety standards changed tremendously, and most old park roads did not meet those requirements.
During the 1960s a change in the tenor of the perception and management of the country's natural resources occurred. The passage of the Wilderness Act was a sign of the times. Consistent with the thinking of environmentalists such as Rachel Carson and Aldo Leopold, understanding the fragility the world's natural resources became a higher priority to land-managing agencies. Appropriate treatment of resources was an issue of high visibility, and a stronger emphasis on environmental concerns spilled over into park road design. When the first official Park Road Standards was printed in 1967, the authors noted that park roads were different than other highways, and because of their locations in highly sensitive ecosystems road width and numbers should be kept to a minimum and treated with the utmost care. The standards also commented on the subtle aesthetics of park roads, their graceful curvilinear alignment, and their gently rounded slopes. The standards put greater emphasis on the natural environment in which the roads were constructed than the National Park Service had previously. Although the aesthetics of park roads remained a strong concern, they often slipped in the priorities of road design.
In the past two decades the evolution of priorities in road design issues continued. During the 1970s and early 1980s, for instance, safety tended to be of paramount importance in design, and all other issues became subordinate to that. The significance of park road design in engineering, architecture, and as part of the cultural landscape emerged during the 1980s. In the past decade controversy often arose on park road projects when issues concerning modifications for the sake of highway safety conflicted with preservation of scenic, cultural, and historical values. In addition, a lack of consistency in dealing with road projects appeared between Federal Highway Administration and National Park Service offices. Part of the problem was the lack of understanding about what features constituted a historic road, why those features were significant, and how they should be managed. Although most managers, designers, and cultural resource specialists could understand the significance of specific architectonic features on a road such as a bridge or tunnel, the other components that contributed to the road's sense of place the character-defining features in the road prism, in the gradient, or in the vistas often remained elusive. Also, the importance of the road in its broader context to the overall pattern of the cultural landscape of the park and region, and its contributions to the history and development of the area sometimes passed unrecognized. In recent years this situation has improved dramatically as more park roads have been evaluated and included in the National Register of Historic Places, and as the Historic American Engineering Record continues its research and documentation work throughout the national park system.
This study was funded to answer some of the questions about the historic development of park roads and their aesthetics nationwide, to provide information on context, and to provide guidance in understanding what features constitute a historic road. Part I of the document includes a narrative history of the development of park roads through Mission 66. Part II includes information on the significant features that make up historic roads. Part III includes appendixes and a bibliography. In the appendixes are examples of some of those features as they developed into accepted design standards during the 1920s through 1941. Mentioned throughout the document are some of the sustainable practices that were used in road development and construction to ameliorate impact on the landscape and resources of national parks.
Managing historic park roads is a complex task. Recently NPS Landscape Architect Charles Birnbaum summarized five essential points for dealing with historic landscapes, of which historic park roads are an essential element. These included (1) establishing a historical context, (2) adopting a comprehensive preservation planning process, (3) acknowledging that rehabilitation would probably be the most practical treatment, (4) networking with allied professionals, and (5) understanding the dynamic qualities of landscapes. All of these apply to the proper management of historic park roads. Yet the impacts that construction and rehabilitation have on historic park roads extend beyond matters of cultural resource management, beyond safety, and beyond aesthetics. Roads will continue to provide access to parks. For most visitors driving the park road is the entire park experience, and that park experience can have a profound effect on people. Environmentalist Aldo Leopold wrote in A Sand County Almanac:
The care with which most park roads were constructed did both.
Facing our national parks today are a number of issues that may threaten the very existence of the parks and the resources within their boundaries. In addition to looking at parks for the scenic, inspirational, natural, and historical qualities, we now must consider the global impact of every undertaking we execute in and around the fragile, limited resources of the earth, including the relatively pristine ones within our artificial NPS boundaries. The political reality is such that national parks will always accommodate visitors. Our agency and our parks were authorized through legislation, and it would be foolhardy of us to believe that they could not be deauthorized in the same way. In the future the importance of parks may lie increasingly in their environmental significance as recharge zones, and as teaching tools for improving our understanding of the earth. But the parks should also remain places for some types of recreation, as well as places for solitude. We must allow access, but how much and of what type are the questions that must be answered, asked again, and answered again as the population of the earth increases.
Thus understanding the management issues connected with historic roads in parks requires a broad vision: studying the history of the area and the importance of the road to the area's development; delineating the physical features that make a park road a significant work of engineering or landscape architecture; accommodating those features in rehabilitation work; and most importantly, comprehending the ramifications of the chosen course of action on the future of that park.
This study would not have been possible without the help of several key people with that broad vision in particular, John Reynolds, Denis Galvin, and Leslie Starr Hart. Others who made significant contributions were James Stewart, Harlan Unrau, Howard Wagner, Terry Goodrich, Mo Miller, Dana Leavitt, Pat Sacks, Ethan Carr, Linda McClelland, Ken Raithel, Robin Gregory, Bob Page, Marcy Culpin, Mark Hartsoe, Eric Deloney, Richard Quin, Todd Croteau, Beth Savage, and Eliot Foulds. A great number of people from various parks and offices of the National Park Service and from the Federal Highway Administration assisted with this document. Thanks to all of you.
The opinions expressed in this document are solely those of the author. Any errors, too, are the author's.