16

Historic Roads

Prepared by Timothy Davis, Lead Historian, National Park Service, Park Historic Structures and

Cultural Landscapes Program INTRODUCTION

Roads have long played a prominent role in shaping the national park

experience. In addition to providing access to natural and cultural resources, park roads are often compelling cultural landscapes in their own

rights. Their sensitive layout, impressive views, rustic guardrails and

picturesque bridges make them highly attractive, especially when contrasted to most ordinary roads and highways. In many cases, the distinctive characteristics of historic park roads serve as defining elements of the

National Park System, creating a sense of continuity from park to park and

providing cherished memories of leisurely excursions through America’s

most beloved landscapes. The appeal of park roads is not limited to the

classic “natural” parks and parkways. Roads play important roles in

national military parks, as well, and contribute to the cultural landscapes of

many historical parks. Even in newer parks, where the influence of

traditional landscape aesthetics may not be as readily apparent, roadways

exemplify changing patterns of park design and resource management.

The consistently compelling character of America’s historic national park

roads and parkways is by no means accidental; nor is its survival guaranteed. Historic park roads such as Glacier’s Going-to-the-Sun Road,

Yellowstone’s Grand Loop, and Sequoia’s Generals Highway reflect the

collective efforts of generations of engineers, landscape architects, and

park administrators. Similar skills and collaborations helped create the

solemn avenues and winding tour roads of National Military Parks and the

exquisitely designed carriage road systems absorbed into the National

Park System in places like Acadia National Park, Marsh-Billings-Rockefeller

National Historical Park, and Washington, D.C.’s Rock Creek Park.

While there is growing appreciation for their significance, many historic
2 L A N D S C A P E L I N E S

park roads are endangered by factors ranging from

natural disasters and age-related deterioration to

growing traffic burdens, evolving technological demands, and increasingly complex legal and financial

concerns. Not only are historic roads among the most

significant categories of cultural landscapes to be found

within the National Park System, but developing

policies for their evaluation and management is one of

the most pressing stewardship challenges facing park

administrators today.

Landscape Line 16: Historic Park Roads provides

guidance to assist in the identification, inventory,

evaluation, and treatment of historic park road resources. Its primary purpose is to serve as a guide for

the preparation of Cultural Landscape Reports (CLRs).

The underlying aim is to promote an approach to park

road stewardship that combines rigorous research and

thorough understanding of legal and technical issues,

with sensitivity toward preservation concerns, aesthetic

considerations, environmental issues, and other

management challenges. Readers will find a brief

account of park road history, an overview of park road

terminology, a guide to research, documentation and

evaluation methods, a summary of pertinent policies

and guidelines, and a brief survey of potential treatment

considerations. This document is meant to be used in

concert with A Guide to Cultural Landscape Reports:

Contents, Procedures, and Techniques and other

publications in the Landscape Lines series. A bibliography is provided to direct researchers to supplemental

material.

This Landscape Line focuses on the major tour roads

that comprise the primary public arteries of the National Park System. While some of these tour ways

incorporated pre-existing roads or road segments, most

were newly developed by the National Park Service for

explicitly recreational purposes and tend to have similar

distinguishing characteristics. There are many other

road types within the National Park Service’s jurisdiction. These range from utilitarian maintenance roads

and administrative networks to historic routes and

traces that predate park development and contribute in

various ways to many parks’ character and significance.

The former rarely require extensive analysis from a

cultural resource standpoint, while the latter frequently

involve complex and highly site-specific considerations

that are beyond the scope of this publication. Many

parks are also traversed by public highways administered by local, state, or federal authorities through

cooperative agreements with the National Park

Service, which have unique management requirements

of their own. While this Landscape Line focuses on

National Park Service-designed and maintained tour

roads, many of the research strategies and treatments

described herein may provide guidance for the

management of related resources in other jurisdictions.

A BRIEF HISTORY OF

NATIONAL PARK ROADS

The first park roads were primitive wagon routes

constructed by private entrepreneurs and the U.S.

Army Corps of Engineers in the late nineteenth and

early twentieth centuries. Tight budgets and the

challenges of operating in remote and often hazardous

terrain produced a pragmatic focus on providing basic

access to key park features. Construction crews

worked with hand tools and horse-drawn machinery

to replace crude pack trails with rudimentary wagon

roads. Road-builders generally followed the dictates of

the existing terrain, occasionally using black powder to

remove stubborn obstacles. Narrow stage roads clung

to steep mountainsides, gaining or losing elevation with

Figure 1. Big Oak Flat Road, Yosemite National Park, 1903.

(National Park Service Historic Photograph Collection

[NPSHPC])
HISTORIC ROADS 3

switchbacks and dangerous hairpin turns. Horse-drawn

stages raised clouds of dusts as they pounded along

simple dirt and gravel surfaces.

Despite these constraints, the engineers and toll road

operators established the foundations of today’s park

road systems, grading roadways, erecting bridges,

constructing masonry retaining walls and safety barriers,

and endeavoring to showcase park scenery without

compromising it in the process. Notable road-building

feats of the period include Yellowstone’s Grand Loop

(1883-1905), Mount Rainier’s Nisqually Road (begun

as a pack trail in the 1880s and improved and expanded

by the Army Corps of Engineers 1903-1910), Rim

Drive at Crater Lake (1913-1919), and the access

roads to Yosemite Valley, which were initially constructed by private turnpike companies in the latenineteenth and early twentieth centuries.

Many of these original roads have been altered substantially, both in location and in terms of width, grade, and

associated features. The same is true of early engineering structures. Mount Rainier’s timber trestles and

Yellowstone’s Golden Gate Viaduct (1884/1900) and

“Chittenden Bridge” (1903) impressed early park

visitors, but they have been replaced by more substantial structures designed to accommodate the demands

of modern automobile traffic. Yosemite retains a few

examples of early park bridge building, from simple

concrete spans to the classic covered bridge at

Figure 2. Tourists on Fall River Road, Rocky Mountain National

Park, ca. 1924. (Rocky Mountain National Park).

Wawona. U.S. Army Corp of Engineer-era bridges in

Yellowstone include the elegant open-spandrel Canyon

Bridge (1915) and a few smaller spans that have been

bypassed or relocated.

The popularization of the automobile in the early years

of the twentieth century created a new era in park road

development. Automobiles were initially banned from

national parks, but these prohibitions were soon relaxed

as park managers joined automobile clubs and hospitality interests in promoting auto tourism as an ideal

means of expanding support for the nascent national

park system. Mount Rainier legalized automobiles in

1907. Crater Lake, Glacier, Yosemite and Sequoia

followed between 1911 and 1913. Yellowstone was

the last to accept cars, admitting motorists in 1915.

The motorization of park transportation had many

advantages. Automobiles were faster and more

comfortable than stagecoaches, greatly reducing the

time and expense of park travel. This made the national

park experience accessible to a larger and more

democratic public, especially when visitors took

advantage of newly developed free auto camps. Park

visitation rose rapidly in the late-1910s and increased at

an even greater rate throughout the 1920s. Replacing

stagecoaches with motorized buses and private automobiles meant that visitors could cover more ground in

a day, so the number of hotels and way stations was

reduced in large parks like Yellowstone.

Park managers quickly recognized that adapting park

circulation systems to accommodate the influx of

motorists would be a difficult, expensive, and timeconsuming process. They also realized that the way

they addressed this challenge would have enormous

impacts on the future of the National Park System.

While it was essential to improve the safety and

convenience of out-dated stage roads, it was understood that road development should be kept to the

absolute minimum needed to provide access to key

park features.

Congress was slow to commit significant funding, but

NPS Director Stephen Mather secured a $7.5 million

road-building appropriation in 1924, which led to a

series of additional budget increases. New Deal

programs such as the Public Works Administration and
4 L A N D S C A P E L I N E S

tration (FHWA), was hailed by both parties as an

exemplary model of interagency collaboration.

The BPR’s engineering expertise enabled the NPS to

undertake a more ambitious construction program than

it could have accomplished on its own. The NPS, in

turn, encouraged the BPR to pay greater attention to

the aesthetic aspects of road construction. While the

NPS established the general parameters of the projects

and prepared most of the architectural treatments for

bridges, guard walls, and related structures, BPR

engineers ensured that proposals were technically

feasible and made many attractive and innovative design

recommendations of their own. The spectacular cliffside location of Glacier’s Going-to-the-Sun Road was

developed by BPR engineers after NPS designers

proposed a technically simpler but more visually

disruptive route. It was this bold yet sensitive solution

that cemented the NPS-BPR collaboration and set the

tone for subsequent park road-building efforts.

The NPS-BPR partnership produced a distinctive

cultural landscape that has become a defining characteristic not just of national park roads, but of the National

Park System in general. NPS landscape architects and 

BPR engineers drew on nineteenth-century carriage

road design techniques, while updating these practices

to accommodate the demands of automobile traffic and

the technical challenges of national park environments.

Figure 3. Going to the Sun Road, Glacier National Park, 1932.

(Glacier National Park)

the Civilian Conservation Corps channeled millions into

park road development during the 1930s. In addition

to upgrading existing roadways, new roads had to be

developed in the many parks that were being added to

the system. Because of the tremendous amount of

high quality work accomplished during the 1920s1930s, this period has been widely regarded as the

“Golden Age” of national park road building. The

character of the current national park road system was

largely established during this era.

The preferred policy was to upgrade existing roads

rather than construct new routes through undeveloped

terrain. Narrow one-way roads were widened,

dangerous sharp turns were eliminated, and grades

were made more gentle and consistent. Pavements

had to be improved, as dirt and gravel surfaces deteriorated rapidly under the stress of automobile traffic.

Safety barriers also became more important, since

vehicles were moving at significantly higher speeds. A

variety of new facilities were developed to accommodate the needs of motorists. These included gas

stations, garages, parking lots, scenic turnouts, expanded

lodging and dining facilities, and enhanced entrance

stations and sign systems. Great care was taken to

ensure that these upgrades were constructed as

sensitively as possible and that new roads and related

developments harmonized with their natural and

cultural surroundings.

This task was overseen by NPS landscape architects

working in close collaboration with engineers from the

U.S. Bureau of Public Roads (BPR). The interbureau

agreement between the NPS and the BPR played a

fundamental role in guaranteeing the aesthetic quality

and technical excellence of park roads. Under this

arrangement, which began in the early 1920s and was

formalized in 1926, the NPS outlined the general

location and aesthetic goals of each project. BPR

engineers then conducted surveys and developed

detailed plans for NPS approval. The BPR supervised

day-to-day construction while NPS personnel monitored projects for conformance with guidelines developed to ensure that park roads exhibited high standards

of design and execution. This arrangement, which still

governs the relationship between the NPS and the

BPR’s successor agency, the Federal Highway Adminis-
HISTORIC ROADS 5

network as possible with various oil-treated gravel or

macadam surfaces. Local rock was often used for the

crushed-stone component of park road pavements.

Not only did this save on material and hauling expenses,

but it helped the roads blend in with their surroundings.

Where excavations were unavoidable, park road

builders tried to minimize disruptions and rehabilitate

areas disturbed during the construction process. Instead

of leaving steep, raw cuts along newly graded roadways,

roadside embankments were sloped back gradually and

rounded to resemble natural contours. Sodding and

planting programs helped stabilize disturbed roadsides

and naturalize their appearance.

Visitor safety concerns led the Park Service to develop

an array of attractive guard wall designs. Constructed of

locally quarried hand-laid stone masonry in most cases,

the walls had a pleasingly rugged appearance and

mirrored the hues and texture of neighboring outcrops.

Both flat-topped and crenellated walls were popular.

Rugged log guardrails were used in many locations and a

few hybrid designs of stone and timber were employed.

The subtle variations among different styles may not be

apparent to casual observers, but the sensation of

driving along winding mountain roadways flanked by

rugged stone or timber barriers became an integral

component of the park experience. Traditional split rail

fences became a similarly characteristic feature of

parkways leading through southern agricultural landscapes. Agricultural fencing and more ornate ironwork

barriers were also present in military parks, mostly

predating NPS-development.

Figure 4. Generals Highway, Sequoia National Park, ca. 1936.

(vintage postcard: Davis)

Park roads were configured to showcase park landscapes in the most attractive and engaging manner.

Where roadside vegetation obstructed appealing views,

trees were cut to create carefully framed vistas. Variety

of scenery was sought to maintain the motorist’s

interest. In forested areas, the distance between the

edge of the road and the treeline was manipulated to

achieve a variety of effects, from a narrow wooded aisle

to a broad green corridor, or an alternating series of

smaller and larger “rooms” carved out of the surrounding woodlands. Trees, shrubs, and unique rock formations were allowed to remain much closer to the

pavement than on conventional roadways, bringing

motorists into intimate contact with their surroundings.

Hazardous curves were eliminated to accommodate

automobile traffic, but prolonged straight-aways were

avoided as much as possible. Sinuous curves were

considered more attractive and curvilinear alignments

allowed road builders to follow the contours of the land

more closely, reducing the need for expensive, environmentally destructive, and visually unappealing excavations. Road widths were narrower than contemporary

highways, rarely exceeding twenty-two feet, with

limited use of shoulders. Curbs were only constructed

on the most highly developed roadways and heavily

used visitor service areas.

The NPS realized that it could not afford to provide all

park roads with modern reinforced concrete or

bituminous “asphalt” paving during this initial improvement campaign, but tried to stabilize as much of its road Figure 5. Roadside revegetation, Glacier National Park, 1933.

(Glacier National Park)
6 L A N D S C A P E L I N E S

While the BPR ensured that park bridges employed the

latest technological advances, the architectural designs

and surface treatments reflected the NPS’s naturalistic

design philosophy. Many bridges were constructed of

reinforced concrete and then faced with rustic stone

veneers. Steel girders were often disguised behind

heavy timbers. As with guard wall construction, NPS

guidelines called for locally quarried stone and random

masonry patterns. Culvert headwalls and retaining walls

were also given rustic stone treatments where they

were visible to the public.

Entrance stations were integral components of the

roadway landscape and similarly embodied the rustic

aesthetic. Architectural treatments varied considerably

within the general rustic framework, however, as

designers employed local materials and evoked regional

building traditions. Southwestern parks often employed

adobe or concrete designed to emulate adobe, while

Appalachian parks and parkways mimicked mountaineer

building practices. Variations on the Colonial Revival

were also popular, especially in eastern historical parks.

Similar policies shaped the design of other visitor

facilities, from comfort stations and concessions to

water fountains and wayside exhibits. The iconic

brown wooden signs familiar to generations of park

visitors became standard features of the park landscape

at this time.

The visual appeal, intimate scale, and rustic associations

of roads constructed during this period profoundly

shaped the way visitors experienced national parks. By

encouraging motorists to slow down and enjoy their

surroundings, moreover, park roads provided an

important management function, exemplifying what

contemporary transportation planners refer to as “traffic

calming.” A leaflet provided to park motorists underscored this philosophy, advising “Park roads are for

leisurely driving only. If you are in a hurry, you might

do well to take another route, and come back when

you have more time.”

A large number of important projects were completed

during this period, producing some of the most

spectacular scenic drives in the world and firmly

establishing the distinctive character of America’s

Figure 6. Classic crenellated stone guardwall, West Side

Highway, Mount Rainier National Park. (Historic American

Engineering Record [HAER] 1993)

Figure 7. Clover Creek Bridge, Generals Highway, Sequoia

National Park. (HAER 1993)

Figure 8. Rustic Entrance Station, Glacier National Park, ca.

1935. (Glacier National Park)
HISTORIC ROADS 7

United States. Recognizing that the vast majority of

visitors would be traveling by automobile, the NPS

outfitted these parks with motor roads from the start.

Engineers and landscape architects combined the lessons

learned in western park construction with new approaches to recreational motorway development

pioneered by eastern parkway designers in places such

as Westchester County, New York. The result was an

impressive collection of scenic roadways located within

a day’s drive of America’s major metropolises.

Shenandoah National Park’s Skyline Drive (1934-39)

exemplified the determination to bring the national park

experience within reach of eastern motorists, along

with the tendency for tour roads to become signature

park features. Great Smoky Mountains National Park’s

most prominent scenic drive was the Newfound Gap

Road. Numerous stone-faced bridges were required to

span the park’s streams but the most striking roadrelated structure remains the “Loopover” at Newfound

Gap (1934), a stone-faced corkscrew bridge that

replaced a series of dangerous and unsightly

switchbacks. Acadia National Park augmented an

existing system of picturesque carriage drives with an

equally scenic series of motor roads designed by the

NPS and BPR.

Parkways played an important role in the NPS’s effort

to reach a broader audience during the 1930s. After

developing Colonial Parkway as a relatively short link

between the historic sites of Jamestown, Yorktown,

and Williamsburg, the NPS greatly expanded the

concept with the Blue Ridge and Natchez Trace

Parkways (authorized in 1936 and 1938, respectively),

which eventually extended well over 400 miles apiece.

These parkways showcased cultural landscapes and

human history along with natural scenery. Split-rail

fences, historic log cabins, and service facilities designed

to mimic vernacular buildings celebrated regional

culture and exposed urban motorists to America’s

agrarian heritage. The location, acquisition, design, and

development of these two extraordinary linear parks

was such an ambitious task that Blue Ridge Parkway was

not completed until 1987 and the Natchez Trace is

only now nearing completion.

Figure 9. Rustic entrance sign, Crater Lake National Park, ca.

1935. (NPSHPC)

national park roads and parkways. Glacier’s Going-tothe Sun Road was widely hailed for its spectacular views

and technical difficulty when it opened in 1933. So

were Rocky Mountain National Park’s Trail Ridge Road

(1932) and Sequoia’s Generals Highway (1935). The

major entrance roads to Yosemite were significantly

rebuilt, with major relocations undertaken to accommodate automobile traffic. The union of engineering

and aesthetics was epitomized in Yosemite’s Wawona

Tunnel (1933), which framed a stupendous view of the

valley that motorist’s could pull over to enjoy in more

leisurely fashion from an observation platform constructed on fill excavated from the tunnel bore.

Yellowstone did not receive any major new roads or

dramatic relocations, but grades and curves were eased,

bridges were upgraded, and oil treatments were

applied to stabilize road surfaces. Mount Rainier’s

Nisqually Road was widened, paved, and straightened

and several new routes were designed to provide

access to previously remote sections of the park.

Numerous other parks received vital improvements to

their road systems during this period.

In addition to adding and improving roadways in the

traditional western wonderlands, the NPS undertook a

major effort to develop additional parks in the eastern
8 L A N D S C A P E L I N E S

As part of a major reorganization of government

bureaus in 1933, the NPS inherited several parkways

and park road systems in the Washington, D.C. area,

including Rock Creek Park, Rock Creek and Potomac

Parkway, George Washington Memorial Parkway, and

the drives along the National Mall and Potomac Park.

The same government reorganization gave the NPS

authority over most of the nation’s military parks.

These unique reservations, intended to preserve and

commemorate significant battlefields such as

Gettysburg, Shiloh, and Vicksburg, were previously

administered by the War Department. Their roads had

been developed by a variety of special commissions to

showcase historic battlefields and associated commemorative elements. Bridges, road surfaces, and

related features were generally constructed to very high

standards due to the reverence accorded these symbolically important sites. The Park Service attempted

to preserve the character of these reservations while

upgrading their road systems to accommodate automobile traffic and increased visitation.

The impressive quality and extent of the roads completed

during the Golden Age of park road development

reflected both the design expertise of the NPS and BPR

and the changing technologies of road building. The

invention of dynamite and adoption of gasoline- and

diesel-powered machinery enabled the NPS to overcome obstacles that had stymied earlier road builders.

New Deal programs also played an indispensable role in

NPS road-building efforts from 1933-1942. While

private contractors conducted most of the highly technical

work, the Civilian Conservation Corps (CCC) and its

predecessor, the Emergency Conservation Work (ECW)

program provided invaluable sources of manpower. The

labor-intensive work of grading and revegetation provided

employment for thousands of CCC enrollees. CCC

workers constructed many miles of guard wall, guardrail,

and stone-lined gutters, along with campgrounds, picnic

shelters and other visitor facilities.

World War II put a temporary end to NPS road building

activities. When recreational travel resumed in the late

1940s, the NPS was not prepared to accommodate the

influx of traffic. New facilities were needed to handle the

ever-increasing numbers of park visitors and years of

neglect had created significant maintenance backlogs.

The situation worsened during the early 1950s, as

expanding automobile ownership, increased leisure time,

and rapidly improving highways brought unprecedented

crowds into the parks. The NPS responded with an 

ambitious ten-year development program called Mission

66, which was intended to bring the parks in line with

contemporary needs in time for the agency’s fiftieth

anniversary in 1966.

Mission 66 resulted in a comprehensive upgrading of

roads and related facilities, along with a significant increase

in the number of parks and a resulting expansion in total

road mileage. Few new roads were built in existing

parks, but many prewar roads were widened, straightened, and paved to accommodate larger, faster, and

more numerous automobiles. Parking lots, campgrounds, and visitor facilities were expanded and a

number of older bridges were replaced with new

Figure 10. Blue Ridge Parkway, ca. 1940.

(vintage postcard: Davis)

Figure 11. Chickamauga Chattanooga National Military Park.

(HAER 1997)
HISTORIC ROADS 9

limited to minor approach roads that did not penetrate

into the heart of undeveloped areas. In 1967 the Park

Service assembled a multidisciplinary panel to develop a

new series of road policies and design standards. The

panel concluded that additional road development

should be kept to a minimum and issued guidelines

intended to ensure that future improvement and

rehabilitation programs would reflect the spirit of

prewar park roads. The panel also advised the NPS to

begin looking at ways to facilitate alternative transportation, leading to the use of shuttle buses in some of the

most crowded parks. The 1969 National Environmental Policy Act helped limit development by mandating rigorous environmental review for major construction projects.NPS park road managers addressed these

challenge in many locations, devising alternative transportation systems for congested areas like Yosemite

Valley and attempting to ensure that new projects were

attractive, safe, and environmentally sensitive. The

FHWA continued to provide technical support and

design guidance. Constructed between 1979 and

1983, Blue Ridge Parkway’s Linn Cove Viaduct exemplified the blending of modern design and technology

with greater ecological awareness. In order to avoid

scarring the hillside, the viaduct was built of precast

concrete segments that were lowered into place by

crane. The complex engineering and elegant, environmentally sensitive design received praise on technological, ecological, and esthetic grounds.

By the 1980s a growing awareness of the historical

importance of park roads was beginning to spread

throughout the cultural resource community. Many

cultural resource managers began to recognize the

importance of preserving historic roads and related

resources, particularly those associated with the Golden

Age of park-road-building between the two World

Wars. Not only was there greater awareness that

these roadways exemplified an important era in Park

Service history, but for many park professionals and

visitors alike, they epitomized the national parks’ role in

twentieth-century American life. The interest in historic

roads was not limited to the grand tour roads of the

classic “natural” parks. Growing appreciation for the

historical significance of roadways has also been seen in

military parks and historic sites. The role of circulation

systems for park administrative and residential areas is

Figure 12. Mission 66 roadway, Natchez Trace Parkway, 1959.

(NPSHPC)

structures better-suited to modern traffic demands. The

rustic design policies that dominated prewar park

development gave way to an explicitly modern approach

that embraced contemporary architectural styles and

materials. The new roads and road improvements were

clearly modern as well, with wider, straighter pavements

and relatively unadorned bridges.

While Mission 66 enabled the National Park System to

accommodate vast increases in visitation, the program

was controversial at the time and continues to be

regarded with ambivalence today. By the mid-1950s,

environmentalists and wilderness advocates were

protesting the program in general and park road

development policies in particular. In addition to

complaining about stripped-downed Modernist

esthetics, critics contended that the NPS was building

too many roads and “improving” others to the point

where they lost their scenic beauty and romantic

appeal. The most controversial of these projects was

the reconstruction of Yosemite’s Tioga Road, which

was ardently opposed by Ansel Adams, the Sierra Club,

and other wilderness advocates. While this project

proceeded as planned, environmentalists successfully

opposed road development in other locations, curtailing

a number of projects such as the extension of the Blue

Ridge and George Washington Memorial Parkways, the

improvement of the Denali Road, and the creation of a

parkway along the historic Chesapeake and Ohio Canal.

By the mid 1960s the Park Service was beginning to

reexamine its road-building policies. In many new parks

in the Pacific Northwest and Alaska, construction was
10 L A N D S C A P E L I N E S

ANATOMY OF A PARK ROAD

The following outline of park road terminology should

help historical landscape architects and cultural resource

managers understand the ways in which roads are

conceived, constructed, and evaluated. Improving

communication among the disciplines involved in

historic road stewardship is essential. Not only do

engineers and landscape architects frequently seem to

speak different languages, but they often use similar

words to mean different things. This can be particularly

confusing in regard to condition assessments and

treatment recommendations. Road conditions that

cultural resource specialists might consider “good” from

the perspective of historic integrity frequently provoke

“poor” ratings from engineers focused on technical

performance. Terms like “reconstruction” and “rehabilitation” also have more pragmatic connotations for

engineers, who are generally less concerned with

maintaining original appearances than with enhancing

safety and efficiency.

Employing a shared vocabulary and developing a greater

awareness of highway engineering concerns will

improve the quality of historic road CLRs while

enhancing interdisciplinary collaboration between

cultural resource specialists, historical landscape architects, and engineers. This brief overview of highway

engineering concerns can also help researchers understand historic plans and design documents.

Highway engineers generally conceive of roads in terms

of three basic components: Plan,Profile, and Profile CrossSection. Section These elements have various subcomponents, all of which may not be present depending on

the age and technical sophistication of the road.

Plan

The basic components of a park road plan are location

and alignment. Location refers Location to the macro-scale

issue of the road’s placement within a park. Location is

determined through the establishment of controls controls, controls

which are typically the significant natural or cultural

features that a road is intended to access, either

physically or visually; or conversely, to avoid, for

technological, environmental, or economic reasons. In

modern usage the term control often refers to addialso gaining attention. Roads built during the Mission

66 program are already being scrutinized for their

significance as resources from an important period of

NPS history.

A number of efforts have been initiated to help protect

and preserve these vital historic resources while educating decision-makers and the general public about the

historic significance and contemporary importance of

America’s national park roads and parkways. Recent

preservation-related activities include a major documentation effort funded by the Park Roads Program and

undertaken by the Historic American Engineering Record,

a surge of nominations to the National Register of

Historic Places, the pending development of a Historic

Roads National Register Bulletin and the designation of

Glacier National Park’s Going-to-the-Sun Road as a

National Historic Landmark. These efforts have encouraged park road managers to pursue policies aimed at

reconciling modern standards of safety and efficiency with

traditional conceptions of landscape aesthetics and

resource stewardship. Glacier, Acadia, and many other

parks have gone to great lengths to preserve the historic

character of their road-related resources.

Figure 13. Linn Cove Viaduct, Blue Ridge Parkway, completed

1984. (HAER 1997)
HISTORIC ROADS 11

drivers’ expectations changed. Curves on historic park

roads were often significantly tighter than the minimum

radii employed on more heavily traveled generalpurpose roadways.

Surveyors established the horizontal alignment of the

road by surveying points at 100' intervals or stations stations

along the centerline of the proposed roadway. These

stations serve as a basis for all future road measurements, which are often expressed as the station number

plus the number of additional feet, eg., station 12+25,

12+35, 12+35.82, etc

Profile

The profile of a profile road denotes the vertical dimensions of

its location. As with horizontal alignment, vertical

alignments, or profiles, were generally calculated to

maximize scenic potential and driving ease while

minimizing construction expense and environmental

disruption. By carefully coordinating the plan and profile

(horizontal and vertical alignments) to follow the lay of

the land as closely as possibly, park road designers sought

to create three-dimensional artworks that blended

tional non-geographical factors as well, such as design

speed, vehicle length, traffic volume, and other cultural

and technological issues. Once controls are established,

road designers assess the best way to link the points,

determining a general road location that balances

aesthetic attributes with pragmatic engineering concerns. After this location is approved, surveyors

establish a precise center-line for center-line the actual roadway.

Horizontal alignment Horizontal alignment Horizontal alignment generally consists of a combination of curves and straight segments, which are

characterized in road-related terminology as horizon- horizontal curves tal curves and tal curves tangents. tangents. Horizontal curves can either

be simple radial curves radial curves, radial curves which are easier to design

and construct but harder to negotiate at higher speeds,

or spiral curves spiral curves of spiral curves constantly varying radius, which are

technically more complex, but visually more appealing

and better-suited for contemporary automobile traffic.

Park road designers generally favored curvilinear

alignments and sought to avoid prolonged tangents as

unsightly and overly conducive to high-speed driving.

While winding roads helped keep speeds within

reasonable limits, the suggested minimum radius minimum radius of minimum radius

curves was gradually increased as vehicles improved and

Figure 14. Typical Maintenance Plan and Section for Park Road or Parkway. (Bayliss 1957)
12 L A N D S C A P E L I N E S

seamlessly with the surrounding terrain. When it was

impossible to follow the natural contours of the land,

designers tried to create a balance between cuts and cuts 

fills in order fills to produce a relatively steady vertical angle

or grade without grade resorting to hauling extra fill from

borrow pits borrow pits or having borrow pits to dispose of excavated spoils

through expensive over-hauling over-hauling or unsightly sidecasting ( casting (a practice casting ( that was putatively proscribed by the

late-1920s but not entirely abandoned in practice). A

ruling grade was ruling grade generally established to excessively

steep climbs and dangerous descents. For automobile

roads in mountainous areas, a 5% ruling grade was

generally considered desirable, though exceptions up to

8% were occasionally permitted. Grades were often

lowered at curves to provide gentler compensatory

grades designed grades to offset the loss in speed induced by

tight curvature.

Cross section

A vertical slice taken across a typical section of the road

is known as a cross section. cross section The cross section

identifies the dimensions, locations, and materials of the

basic park road structure and characterizes its immediate surroundings (sometimes referred to as the road

prism). prism Cross section components include pavement,

base (or “subgrade” ), shoulders, medians (if present),

curbs, gutters or other drainage systems, side slopes,

tree-line (or “clear-zone”), and additional features such

as safety barriers, retaining walls, signs, lighting, etc.

Figure 15. Illustrative section showing pavement, drainage, coping stone and path, Eagle Lake Motor Road, Acadia National Park,

1993. (Foulds/NPS 1993)

A typical section typical section is usually generated to guide the

development of a roadway or component project;

alternative sections are often developed to address

changing topographical conditions or other design

concerns. Cross sections for new construction

generally depict the pre-existing ground level as a

reference for grading or filling operations.

The typical pre-automotive park road pavement pavement often

began as a simple graded dirt surface. Most park roads dirt 

were eventually improved with gravel, gravel crushed

stone, or stone, macadam macadam (crushed stone bound together

with progressively finer particulates). Early accounts will

occasionally refer to these processes as “metaling.” On

more substantial park roads, a crushed-stone base

course or course sub-grade sub-grade enhanced the stability of the

travelway. As automobiles rendered these surfaces

obsolete, various binding materials were employed to

create more durable pavements. Penetration oil Penetration oil and Penetration oil 

asphaltic asphaltic compounds compounds were compounds applied directly to

existing gravel or macadam surfaces, temporarily

alleviating dust and deterioration problems and creating

hybrid pavements such as bituminous macadam. bituminous macadam

More substantial Portland cement concrete

pavements enjoyed considerable popularity in the

1920s-30s, especially for heavily trafficked parkways,

where rigid concrete’s enhanced durability and superior

smoothness justified the additional cost. By the 1940s,

bituminous concrete – bituminous concrete crushed stone mixed with

bituminous compounds either on site (road mix) or in (road mix
HISTORIC ROADS 13

a central or portable plant (plant mix) – became the plant mix

most common paving material, especially as durability

and performance improved through additional research.

All these surfaces required substantial and well-drained

sub-grades.

In addition to specifying the width, thickness, and

consistency of the pavement and base, the cross section

characterizes the geometry of the surface. Preautomotive roads were conspicuously convex, with a

high central crown that crown shed water into roadside

ditches ditches. While ditches raw, unimproved ditches were the

norm for most early park roads, paved gutters paved gutters lined

with native rock or cobblestone were often constructed

when erosion problems existed or appearance was a

significant concern. The traditional crown-and-ditch

configuration posed significant safety hazards as operating

speeds increased, but improved pavements were

capable of shedding water with a minimal central rise.

Traditional deep and narrow ditches gradually gave way

to broader and shallower configurations that were

more forgiving to errant automobiles. Replacing ditches

and gutters with underground drainage systems drainage systems

further enhanced safety and roadside beauty. Curbs

were often employed to channel water into curb or curb or

drop inlets drop inlets, where it drop inlets was directed away from the

roadway using drains and drains culverts culverts. culverts Culverts were

also used to channel minor water sources under the

roadway. The visible component of the culvert, or

headwall headwall, was headwall usually accorded a compatible treatment if it could be seen by the visitor. Higher speeds

also necessitated the introduction of superelevation, superelevation

or banking, which tilted the pavement in complex

three-dimensional arcs to counteract centripetal forces.

Early park roads were barely wide enough to accommodate one carriage or stagecoach. By the mid-1920s, park

road standards called for 18'-22'-wide driving surfaces,

which were considered wide enough to allow oncoming

autos to pass safely. As late as the 1950s, 22' was

deemed a sufficient width for most two-lane park roads.

Park road pavements were occasionally flanked by 3'-4'

graded shoulders shoulders. shoulders Shoulders were often turfed after the

construction process; in other cases, depending on the

erosion potential, nature was simply allowed to take its

course. Rural parkways typically followed park road

standards for pavement and shoulder width, while

suburban commuter routes such as George Washington

Memorial Parkway and Baltimore-Washington Parkway

were constructed with four-lane pavements forty-feet or

more in width. By the 1940s, planted medians medians of medians

varying width separated opposing lanes of traffic on highvolume parkways.

Park road development often required cutting into

slopes or filling depressions to provide a sufficiently wide

and stable roadbed. The cross section typically provided a grading profile that grading profile stipulated the desired

angle and contours of cut slopes cut slopes and cut slopes fill slopes fill slopes. fill slopes

While conventional highway engineers favored flat

slopes and steep 1:1 angles, park road designers

preferred more gentle 2:1, 3:1, or even 4:1 slopes

rounded to resemble natural topography. It was not

always possible to maintain these ideals in steep and

rocky terrain. Many park roads are bordered in part by

nearly vertical rock cuts, retaining walls retaining walls retaining walls of hand-laid

stone, cement-rubble, or rip rap, or by log, steel, or

concrete cribbing, cribbing rock-filled wire-mesh gabions gabions, or, gabions

more recently, mechanically stabilized earth. mechanically stabilized earth

Safety barriers Safety barriers are Safety barriers another component of the cross

section. Typical historic park road safety barriers include

dry-laid stonewalls dry-laid stonewalls, dry-laid stonewalls mortared stonewalls mortared stonewalls, and mortared stonewalls

log ortimber guide rails timber guide rails. timber guide rails Later modifications may

include stone-faced concrete-core walls stone-faced concrete-core walls, stone-faced concrete-core walls steelbacked timber guardrails backed timber guardrails, backed timber guardrails w-beams w-beams of w-beams galvanized

or Cortan steel Cortan steel, and Cortan steel simulated stone barriers

Figure 16. Typical guardwall details by Division of Landscape

Architecture, ca. 1930. (NPS)
14 L A N D S C A P E L I N E S

Viaducts Viaducts share Viaducts many design and construction characteristics with bridges but function primarily to carry

roads over inhospitable terrain such as steep slopes and

deep ravines, where they often pose attractive and

environmentally appealing alternatives to extensive

excavations. As with park bridge design, their visible

components were often harmonized with the surrounding landscape with rustic stone veneers.

Tunnels Tunnels can Tunnels also minimize the visual and environmental impact of park roads, concealing their presence along

sidehills and allowing road designers to bore through

spurs and outcrops instead of drastically reconfiguring

them. When a spur or outcrop was not considered

significant enough to warrant the expense of tunnel

construction, daylighting the daylighting roadway by leveling the

outside of the cut opened up views and produced a

more naturalistic appearance. Tunnel characteristics

that should be noted include basic dimensions, portal

configuration and materials, number and nature of

windows or adets (if adets present), significant views from

portals (if present), and overall landscape design and

orientation considerations.

Associated Features

The following features can also contribute to the appearance and significance of park road landscapes. Their

location, physical characteristics, and development should

be addressed in park road histories, existing condition

documentation, and treatment plans. The extent to

which these features are discussed will depend on their

perceived significance and impact on the park road

landscape.

Scenic pullouts Scenic pullouts and Scenic pullouts waysides waysides are waysides integral components of park road landscapes. Their location, configuration, paving materials, drainage considerations, curbing

and associated planting design should be described and

analyzed in the same manner as the main roadways.

Architectural features such as comfort stations comfort stations and comfort stations

wayside exhibits wayside exhibits ranging from simple resource

identification to more elaborate interpretive efforts should

also be considered. Even such mundane features as

picnic tables, benches picnic tables, benches, picnic tables, benches trash receptacles trash receptacles, and trash receptacles

water fountains water fountains water fountains should be described and evaluated for

their design implications and historical significance.

comprised of reinforced concrete molded and colored

to resemble authentic stonework. Guardwalls Guardwalls and Guardwalls

guardrails guardrails are guardrails sturdily constructed to protect vehicles

from roadside or median hazards. Guiderails Guiderails and Guiderails

guideposts guideposts are guideposts generally less substantial and are

intended to delineate the roadway or warn of roadside

hazards. Curbs also help Curbs to delineate roadways,

though their use is generally restricted to higher volume

parkways, urban park roads, and developed areas such

as parking lots, scenic pullouts, and visitor centers. Park

roads may also be bordered by ornamental fencing

of stone,iron, or iron wood.Split-rail Split-rail Split-rail fencing is particularly prevalent in southeastern parks.

The cross section may also depict the location of

significant natural or cultural features, and delineate the

desired setback of the tree-line, which tree-line can be varied

for scenic effect. As speeds rose and safety concerns

mounted, this line has generally been pushed further

away from the travel surface to create a broader

recovery zone free of recovery zone obstacles that might endanger

errant motorists. The placement of signs, lighting

standards, and other roadside features can also be

depicted in the cross section.

Major Structures

Bridges and other major structures are integral components of park road landscapes, but they are generally

evaluated independently, both for maintenance purposes and to determine their cultural significance as

engineered or architectural features. The CLR and

related research activities should address these structures in regard to broader landscape concerns, detailed

technical analyses or construction histories are generally

unnecessary.

When analyzing a bridge for CLR bridge purposes, it is

important to describe its location and appearance and

characterize its contributions to the overall park road

landscape. Brief descriptions, construction chronicles,

and contextual information relating specific structures to

broader NPS trends should be sufficient in most cases.

The basic structural system should be identified, the

surface treatment described, dimensions noted, and

siting issues discussed, along with any significant historical

associations or modifications.
HISTORIC ROADS 15

Figure 17. Obsidian Creek Interpretive Wayside, Yellowstone

National Park. (HAER 2000)

Signs are fundamental aspects of park road landscapes. Signs

Their location, content, and design details should be

described, along with any available information about

their placement and evolution over time. Entrance

signs can be particularly signs significant, in both visual and

symbolic terms. Many parks retain historically significant

entrance signs dating to park road development in the

1920s and 1930s. The significance of Mission 66-era

signs and roadside interpretive strategies is also becoming

increasingly appreciated. Historical parks — and commemorative military parks, in particular — often contain

a higher density of informational signs and commemorative markers. These signs and tablets tablets may have tablets

considerable historical significance. Statues Statues and other Statues

memorials memorials may memorials contribute to the appearance and

significance of park road landscapes and were often sited

and designed in reference to circulation systems.

Roadside lighting is Roadside lighting another associated feature that

may affect the visual character of park road landscapes

and can exhibit significant geographic and temporal

variation.

Entrance stations Entrance stations, when Entrance stations present, are highly significant

road-related features that play important roles in shaping

visitors’ perceptions of park road landscapes. While

detailed consideration is best reserved for historic

structures reports or independent determinations of

eligibility, their location, appearance, and basic history

should be related in the CLR.

Similar considerations apply to facilities such as visitor visitor

centers centers, centers campgrounds campgrounds, campgrounds and maintenance areas maintenance areas, maintenance areas

which were often developed in association with park

roads and significantly affect their location and related

visitor experiences, but will generally merit independent

analysis.

Figure 18. Sprague Creek Campground, Glacier National Park.

(HAER 2000)
16 L A N D S C A P E L I N E S

The View from the Road

The preceding elements all contribute to the motorist’s

impression of park road landscapes. Planting plans and

vegetation management also play important roles in

shaping the view from the road. The art of park road

design entails manipulating these components to

produce appealing visual effects. The various elements

must be combined in a unified and harmonious manner

that can be appreciated by motorists moving at slow to

moderate speeds. Since road construction frequently

disrupted the surrounding terrain, park road designers

also employed remedial landscaping to conceal their

interventions so that motorists could believe they were

traveling through undisturbed natural and cultural

settings.

The emphasis on native materials and naturalistic design

also shaped the development of planting plans planting plans and planting plans

vegetation management vegetation management vegetation management schemes. When planting or

roadside revegetation revegetation efforts were called for, park

road designers generally worked with native species

arranged in naturalistic groupings – though definitions of

these terms have evolved significantly over time. Many

“native” materials were acquired from commercial

nurseries and transported significant distances to

supplement locally transplanted specimens. Historic

planting designs occasionally incorporated exotic plant exotic plant

materials materials. materials In these cases, non-native roadside plants

may have historical significance and should be treated

accordingly.

Subtle variations in roadway alignment allowed for

specimen tree preservation specimen tree preservation and the retention of

other natural or cultural features. Roadside cleanup

programs programs programs removed downed timber from the

motorist’s view, creating a more manicured appearance

than is found in most parks today. Other tools for

managing the view from the road included scenic

easements easements and easements agricultural leases agricultural leases, agricultural leases which were

intended to prevent conflicting land uses and promote

traditional farming practices that reduced maintenance

costs while enhancing the roadside’s visual and symbolic

appeal. While the resulting landscapes may appear

natural to contemporary observers, evidence of these

design practices can often be found in documentary

sources and historic photographs.

Park road designers also employed sophisticated

strategies to choreograph scenic effects. Inserting a

slight tangent to produce prolonged axial views axial views was a axial views

popular way of showcasing significant scenery, as was

aligning the roadway so that compelling features

appeared on the outside of curves. Natural rises and

ridge crests could be used to provide sweeping panoramas. oramas Vista cutting was Vista cutting a common means of

creating attractive views in forested terrain. Canopy

views, where only the lower branches were removed, views

afforded a more subtle variation of this strategy. While

subsequent vegetation growth has occluded many of

these historic designed vistas historic designed vistas, their location and

purpose can often be identified by historic documents,

plans, and photographs. By manipulating alignment,

profile, vegetation, and other roadside features park

road designers also controlled the motorist’s sight

distance, distance balancing the desire to produce visual variety

and picturesque intimacy with the need to ensure safety

at reasonable driving speeds.

Understanding all of these elements – plan, profile,

cross-section, major structures (bridges, viaducts,

tunnels), associated features (scenic pullouts, waysides,

historic wayside furnishings, architectural elements,

lighting, entrance stations, visitor centers, campgrounds,

maintenance areas), planting design, views and vistas –

enhances the cultural landscape researcher’s ability to

identify historic park road characteristics and development patterns, evaluate their significance, and propose

appropriate treatments and stewardship programs.

HISTORIC ROADS AND THE CLR

Managing America’s national park roads has become an

increasingly complex task. Not only has the number of

visitors increased markedly, but most park roads were

designed for significantly shorter and lighter vehicles

moving at slower speeds than are common today.

Technical challenges have been exacerbated by the fact

that many historic roads are showing their age and

require extensive maintenance, repair, and rehabilitation. New engineering standards, enhanced liability

concerns, and multiplying regulatory frameworks

require contemporary road managers to be conversant
HISTORIC ROADS 17

with a broad range of technical, legal, and bureaucratic

issues. Changing visitor expectations also place conflicting demands on historic road managers: while some

motorists relish the opportunity to experience the

intimate scale and leisurely pace traditionally associated

with park travel, others are intent on arriving at the next

destination as quickly as possible.

The Cultural Landscape Report (CLR) can play an

important role in the treatment of historic road

resources. In addition to proposing specific solutions to

immediate resource challenges, the CLR’s historical

narrative, site survey, analysis, and treatment recommendations can contribute to the development of

General Management Plans, Environmental Impact

Statements, and National Register Nominations and

Determinations of Eligibility. The CLR’s primary

purpose, however, is to formulate a comprehensive

stewardship plan that guides specific landscape treatment

activities and sets broader, long-term preservation goals.

The decision to develop a CLR for a historic road will be

based on the resources’ perceived significance and the

degree to which it constitutes a distinctive cultural

landscape in relationship to the broader context of the

park. In many cases, historic roads can be considered

contributing elements to larger cultural landscapes, in

which case they are most appropriately discussed in the

circulation section of more broadly scoped CLRs. If the

historic road possesses a distinct character as an identifiable cultural landscape in its own right, or constitutes a

complex managerial challenge that requires specific

treatment solutions that may not be applicable on a parkwide basis, then an independent CLR is probably

warranted. In situations where a historic road is the

dominant feature of a park, the road CLR may be the

most appropriate framework for addressing treatment

options for associated landscape elements.

The scope of a historic road CLR will depend on the

nature of the resource, the availability of research

materials, and the park’s general management goals and

specific road-related concerns. The CLR should define

the site boundaries, document the road’s history and

current conditions, articulate its character-defining

features, identify the range of stewardship challenges to

be addressed, and outline a treatment plan that proposes

appropriate solutions that conform to all relevant managerial goals, policy guidelines, and regulatory frameworks.

The historic road CLR should include an introductory

overview, a site history, existing condition descriptions, an

analysis and evaluation section, a treatment component, a

record of treatment, and associated bibliographies,

graphic material, and supplemental documentation. The

general format and content of the CLR are described in

more detail in A Guide to Cultural Landscape Reports:

Contents, Processes, and Techniques. This Landscape

Line supplements the basic CLR guidelines with information tailored specifically to the challenges of historic park

road stewardship.

A CLR will be more effective if it is completed before

the planning and design phases of related road projects

are finalized. The CLR team should work closely with

park staff, regional cultural landscape specialists, and the

NPS Park Roads and Parkways Program in order to

identify upcoming projects that might impact historic

park road resources. Ideally, a CLR should help set the

broader goals and specific treatment recommendations

for road projects, and not serve as a remedial document

calling for amendments to proposals developed along

more narrowly technical grounds.

Unless a road has been determined eligible for the

National Register of Historic Places, however, cultural

resource specialists do not typically have an official role

in park road projects. When cultural resource specialists

are included in the planning process, their ability to

implement preservation-oriented treatment plans is

generally more limited than when dealing with resources over which they have more independent

control. Fortunately, park road management has

become an increasingly multidisciplinary process. By

collaborating in the planning and design process, cultural

resource specialists can help produce more historically

appropriate and context-sensitive solutions.

Since park road management is a complex

multidisciplinary endeavor, it is important to examine

materials and consult specialists in relevant fields such as

history, archeology, natural resource management,

planning, compliance, and interpretation. Sidebar 1

provides a list of planning, management, research, and
18 L A N D S C A P E L I N E S

General Management Plan [GMP]. As the first phase of

planning for a national park service unit, a GMP ensures that each

park has a clearly defined direction for long-term resource

preservation and visitor use. GMPs typically contain mission

goals and management prescriptions that address the preservation of park resources, types and areas of development, visitor

carrying capacities, and potential boundary modifications.

Historic roads stewardship concerns should be addressed when

developing new GMPs.

Historic Resource Study [HRS]. A HRS for a park evaluates

cultural resources within historic contexts. Through documentary research, typically led by a historian, and field investigations,

the HRS narrative describes the resource’s history, integrity,

authenticity, associative values, and significance. The HRS

includes National Register nominations for qualifying resources

and is a principal tool for completing more detailed studies.

Historic Structures Report [HSR]. A HSR is the primary

guide to treatment and use of a historic structure. The purpose,

content and use of the report parallel that of a CLR. HSRs may

exist for bridges, tunnels, entrance stations, and other major

structures. The treatment and use of a major road feature, such

as a bridge or tunnel, or associated road feature, such as an

entrance station, should be determined in conjunction with the

overall stewardship strategy of the road. 

List of Classified Structures [LCS]. The LCS is an evaluated

inventory of all prehistoric and historic structures in the

National Park System having historical and/or architectural/

engineering significance. The LCS provides baseline data for a

park, including the location of prehistoric and historic structures,

description, historical significance, and management decisions.

Any constructed historic park road feature may be found on the

LCS.

Cultural Landscape Inventory [CLI]. The CLI is an evaluated

inventory of all cultural landscapes in the National Park System

that are listed in or eligible for the National Register of Historic

Places. The CLI provides baseline data for a cultural landscape,

including roads and road-related resources. Information

recorded in the inventory includes location, physical description,

historical chronology, period of significance, landscape characteristics, and management decisions.

Archeological Overview and Assessment. This report

describes and assesses known and potential archeological

resources in a park area. The overview summarizes existing

archeological data while the assessment evaluates the data.

Further investigation requires an archeological identification and

evaluation study to identify the location and characteristics of

some or all sites in an area. Data is entered into the Archeological Sites Management Information System (ASMIS).

Ethnographic Overview and Assessment. This document

reviews existing information on park resources valued by

associated traditional communities. The information comes

from archives, publications, and interviews with community

members and other stakeholders.

National Register of Historic Places. The National Register

of Historic Places lists numerous park roads and related

features. The National Register Information System (NRIS)

database should be consulted for relevant listings. The full text

of nominations and copies of supporting documentation can be

obtained by contacting the National Register or may be available

in park files.

Historic American Engineering Record (HAER). From

1988 to 2002 HAER conducted an extensive survey of National

Park Roads and Parkways. HAER reports typically include a

comprehensive narrative history, individual reports on bridges

and tunnels, measured and interpretive drawings, and extensive

large-format photographic documentation. The HAER collection

should be consulted to determine if the road under consideration has received this level of documentation.

Road Inventory Program (RIP). The FHWA’s Federal Lands

Highway Program (FLHP) maintains a videographed inventory and

associated condition assessment for all paved NPS roads. A

pavement surface-condition rating is also provided. The videos

often contain information on historic features, landscape

character, and general road conditions.

Bridge Inspection Program (BIP). The FHWA also

inventories and inspects NPS bridges. An evaluation of each

bridge’s load-carrying capacity is performed to determine if any

deficiencies exist; if necessary, appropriate action such as

warning signs, bridge closing, rehabilitation or replacement, is

recommended. In addition to basic structural data, BIP reports

may contain information on historic aspects, materials and

conditions.

Servicewide Traffic Accident Reporting System (STARS):

STARS is a NPS Park Roads Program database that provides

information on the location, frequency, and severity of traffic

accidents. This information is critical for maintaining road safety.

It can also demonstrate historically low accident rates for park

roads or park road segments that can be used to justify design

exceptions or counter proposed “upgrades” that adversely

impact historic road features.

Traffic Monitoring System: The NPS Park Roads Program

monitors traffic in thirty-three of the most heavily used park

units. The selection of parks is periodically adjusted in response

to visitation trends. If the road under study is part of this group,

the data can be useful for formulating treatments and policies.

SIDEBAR 1: PLANS, REPORTS, AND INVENTORIES THAT MAY PROVIDE TECHNICAL DATA OR PLANNING GUIDELINES OF USE IN DEVELOPING THE CLR.
HISTORIC ROADS 19

contexts in which these developments occurred; and

the ways in which designers, park managers, visitors,

and other commentators responded to the roadbuilding process and products. Once these factors are

clearly understood, it is possible to make informed

judgments about a historic road’s character, significance,

and integrity–key components of the CLR, the National

Register of Historic Places review process, and cultural

resource management in general.

Park road histories should be developed by researchers

or teams of researchers with demonstrated expertise in

historical research and writing. Depending on the

character of the historic road and the resources

available, other professionals may be involved, including

highway engineers, historical landscape architects,

horticulturalists, historical architects, and cultural

anthropologists. The historical report should be peerreviewed and edited to conform to current professional

standards. Additional information on the preferred

format can be found in A Guide to Cultural Landscape

Reports: Contents, Process, and Techniques.

The park road history should generally take the form of

a chronological narrative tracing the resource’s inception, development, and evolution. When writing the

history of a park with multiple roads, it may be easist to

provide a general context covering road development

issues on a park-wide basis and then trace the evolution

of individual roads in separate sections. In the case of

particularly long roads such as national parkways, an

overview of the broader goals and history of the project

should be followed by sections on discrete segments of

the resource divided according to logical administrative,

geographic or temporal boundaries. After tracing the

development of individual sections, it is generally

advisable to assess the project’s impact and reception as

a whole, chronicling subsequent modifications and

management issues on an as-needed basis. Sidebar 2

provides a checklist of concerns that should be addressed in the history portion of the CLR.

While the historical narrative will reflect the individual

nature of every project, the concerns that the historian

should attempt to cover include: the broader cultural

currents and site-specific issues that gave rise to the

project; the major agencies and individuals involved; the

evolution of the design scheme or schemes; the details

inventory documents that can contribute to the

development of a historic road CLR. All of these

materials may not be available for every historic road

resource, but efforts should be made to locate and

examine relevant studies early in the CLR development

process.

Formal public outreach is generally beyond the scope of

the CLR, but it is important to consider visitor perspectives and the needs of adjacent communities. Involving

the public in the planning stages of park road stewardship is generally a wise and effective strategy. When the

public is not informed until late in process, ill feelings

may occur and treatment may be delayed while

differences are resolved. In many cases, public opinion

can also play an important role in fostering support for

the preservation of historic park road landscapes.

By synthesizing a wide range of technical, cultural, and

natural resource-based material and carefully evaluating

resource capabilities and programmatic concerns, the

historic road CLR provides a broad-based framework

for ensuring that park road stewardship embodies

technically appropriate, context-sensitive, and historically

informed design solutions and management strategies.

HISTORICAL RESEARCH

The successful stewardship of park roads requires a

thorough understanding of the history of the resources

under consideration. By discovering the site-specific

concerns and broader contexts that motivated roadbuilders, establishing the initial “as-built” conditions of

the resources, tracing their evolution over time, and

understanding the ways in which earlier visitors experienced and valued them, historical research can help

contemporary road managers evaluate the significance

and integrity of historic roads and formulate appropriate

policies for their stewardship and interpretation.

Historical research should be conducted to determine

the original condition of the site; the goals, methods,

and results of the initial road-building project or

projects; the subsequent evolution of the road(s), roadrelated features, and surrounding cultural landscapes;

the social, technological, aesthetic, and bureaucratic
20 L A N D S C A P E L I N E S

of the construction process with particular attention

paid to unusual, innovative, or paradigmatic practices or

technologies; the ways in which these practices

accorded with or differed from standard engineering

procedures and broader trends in park road development; and the basic dates and legislative and financial

parameters of the project. Original completion dates

and as-built conditions should be described, along with

related ceremonies or reactions to the project or its

components. Similar information should be presented

for roads that were developed by non-NPS entities or

individuals, insofar as available sources permit

Since park roads and their surroundings tend to evolve

over time, it is important to trace subsequent alterations

along with the social, environmental, or technological

factors that influenced these changes. Gauging popular

responses to park road building practices by surveying

tourist literature, travel diaries, and similar sources can

provide important insights into the ways in which park

roads were experienced and given meaning by their

intended audiences. These reactions help establish the

historical significance of a road or related resource.

Popular and professional commentary often played an

important role in shaping subsequent alterations to park

roads and related resources.

Important primary sources for park road research include

park legislation and the records of related hearings,

superintendent’s reports, planning documents, construction reports, correspondence between key figures, and

maintenance and management reports that chronicle

post-construction changes and concerns. Historic plans

and construction photographs afford invaluable insights.

The quality and availability of these documents vary

considerably. Some parks have maintained extensive and

well-cataloged historical collections; others have not. In

general, it is easier to find documentation for projects

completed prior to the 1950s, but significant amounts of

later material can often be found. Documentary sources

for roads that were developed by other agencies and

individuals prior to NPS acquisition are generally harder

to locate, if they exist at all.

Park archives often contain the most pertinent information, but supplementary material can frequently be found

in state and local historical collections, university libraries,

and independent research centers. These repositories

may be particularly useful for researching pre-NPS road

development. The National Archives and Records

Administration (NARA) center in College Park, Maryland,

the various regional NARA repositories, and regional Park

Service collections and records centers should be

checked for official correspondence and other records.

The NPS Denver Service Center’s Technical Information

Center (TIC) is an important source of design drawings

along with related textual materials. The National

Register of Historic Places database should also be

consulted to determine whether or not roads and related

features are listed, in which case the nominations may

provide considerable information.

It is generally useful to look beyond the official administrative record and try to find accounts of park road development and related issues in contemporary newspaper and

magazine articles, in travel books, and in tourist brochures, automobile club bulletins and related ephemera

such as postcards, scrapbooks, diaries, and letters. Local

libraries and historic collections can be particularly

valuable sources in this regard. Oral histories may be

available for some projects, especially those involving the

Civilian Conservation Corps.

A number of professional journals and popular periodicals

routinely covered park road-relates subjects. These

include: American Civic Annual, American Forests,

American Highways, American Planning and Civic Annual,

American Motorist, City Planning Civil Engineering,

Engineering News-Record, Landscape Architecture

Quarterly, Parks and Recreation, Public Roads, Traffic

Quarterly, Transactions of the American Society of Civil

Engineers.

Historians should conduct as much original research as

the project’s scope permits, but it is advisable to make

use of secondary sources to maximize efficiency and

avoid redundancy. The bibliography lists a number of key

works on the history of American parks, landscape

architecture, highway engineering, and related social

trends. Valuable information can often be found in NPSproduced secondary sources such as historic resource

studies, administrative histories, special resource studies,

historic structures reports, cultural landscape reports,

archeological surveys, HAER documentation, and

National Register nominations and Determinations of

Eligibility.
HISTORIC ROADS 21

NPS theme studies provide valuable contextual information and should be consulted and invoked where

appropriate. Some of the most pertinent for park road

research include Landscape Architecture in the National

Park Service, Rustic Architecture in the National Park

Service, the Civilian Conservation Corps, Mission 66 Visitor

Centers, and the forthcoming Mission 66 Planning,

Architecture, and Landscape Design. A brief history of

NPS road development accompanied by extensive

graphic documentation and construction details can be

found in America’s Park Roads and Parkways: Drawings

from the Historic American Engineering Record (Davis,

Croteau and Marston 2004). While it is important to

summarize contextual information, the historian should

not attempt to provide a comprehensive history of these

topics within the scope of a CLR.

Since CLRs address resources that are potentially eligible

for listing on the National Register of Historic Places, it is

important for historians to be aware of the procedures,

concerns, and terminology that factor into this process.

Explicitly linking a road’s development to authoritative

theme studies and identifying primary periods of significance will facilitate subsequent evaluation procedures. It

may also be desirable to make connections with the

broader themes and patterns of American history

articulated in various National Register and NPS Park

History program publications. These alternative themes

may be particularly useful for contextualizing roads that do

not fit the pattern of classic tour road development.

Historical research should provide practical guidance for

maintenance, preservation and rehabilitation activities.

Archival research can help identify the appearance and

location of historic features, playing a key role in existing

condition surveys and condition assessments. Historic

design details and construction processes can be used to

repair or reconstruct lost or impaired features.

CLR research may also lead to a park road’s recognition

as a National Historic Landmark, a National Historic Civil

Engineering Landmark, a National Scenic Byway or an

All- American Road. All of these designations will have

important implications for subsequent management

practices and for the development of specific treatment

plans.

Park road research can also serve important educational

and public relations functions. Building a broad constituency for historic roads is a crucial component of park

road stewardship. Public presentations of park road

history through various interpretive media can raise

public awareness of the historic attributes and cultural

significance of these under-appreciated resources.

Popular support for park road preservation can be

particularly effective in the case of major reconstruction

projects for which the National Environmental Policy

Act requires mandatory public review.

SIDEBAR 2: HISTORICAL RESEARCH

CHECKLIST

Historic Context

• Themes or associated events (social, political, economic,

environmental) that influenced road development or use °

Adherence to local, regional, or national design standards

Development History

• Evidence of prehistoric use or associated sites

• Agencies and individuals involved

• Legislative and financial parameters of the project

• Evolution of design scheme

• Designers and builders of the road, design intent, width,

grade, origin, route or alignment, destination, views, natural

features, cultural sites, dates of construction

• Materials used and sources

• Tools and equipment used for construction and maintenance;

unusual, innovative, or paradigmatic construction techniques

or technologies; ways in which these practices accorded

with or differed from standard engineering procedures and

broader trends in park road development

• Types and extent of features such as paving materials,

drainage systems, retaining walls and barriers, tunnels and

bridges, plant materials

• Completion dates, as-built conditions, ceremonies held,

responses in popular and professional publications

Management History

• Location and frequency of road repairs or rationale for

closures and reroutes

• Successes and failures of maintenance solutions

• Changes in location, design, materials, or use, along with

information about social, environmental, or technological

factors influenced these changes
22 L A N D S C A P E L I N E S

EXISTING CONDITIONS

DOCUMENTATION

The documentation of a historic road’s existing condition

is a critical component of the CLR process. Existing

condition documentation should be based on detailed

fieldwork and provide a comprehensive survey of the

site’s features along with assessments of their current

condition. By providing a precise record of significant

landscape features, the existing condition survey makes it

possible to evaluate a site’s historic integrity, identify

stewardship concerns at both macro and micro levels,

and provide a baseline for the treatment recommendations and subsequent implementation and monitoring

activities.

Before conducting the survey, the CLR team should

review existing historical information and graphic materials. Historic plans, maps, and photographs should be

consulted to assist in the identification and evaluation of

road features. Contemporary data sources such as

maintenance reports, the Cultural Landscape Inventory

(CLI), the List of Classified Structures (LCS), Facility

Management Software System (FMSS), and the FLHP’s

Road Inventory Program (RIP) may provide further

guidance. Park resource managers, engineering personnel and maintenance staff can offer invaluable assistance

based on their firsthand knowledge of historic road

resources.

This background information should be consolidated and

compiled in formats that allow easy reference in the field.

The location and character of key features such as vistas,

pullouts, bridges, drainage systems, safety barriers, and

other associated landscape elements should be noted for

inspection in the field. If a road system is complex, or

excessively long it may be desirable to divide the road

into discrete segments according to logical geographic

boundaries or historical development patterns. The CLR

team should consult with park administrators, who may

have already divided the road into management subunits.

Consistent boundaries, terminology, and resource

identification will facilitate all phases of the CLR process

and make the results more useful for park staff and other

potential partners.

A clean base map is essential for developing existing

condition documentation. Depending on the scale of the

road system or individual road, a USGS map of

1:24,000 or a more detailed map may be appropriate.

In some cases, both scales will be useful. At the general

survey level for a park road system, park road, or

parkway, base maps should portray basic information

such as road alignments, typical pavement widths, bridge

locations, safety barrier types and locations, significant

road features, principal vistas, and distinguishing landscape

characteristics for various road segments. It is critical to

keep precise records that identify the name of the road

or road segment, the location of features (either in

distance from a prominent intersection or, for more

precision, in reference to official station numbers found

on engineering documents) and their materials, dimensions, construction style, and condition.

For a comprehensive inventory or to guide specific

treatment actions, more detailed maps and drawings

may be needed to adequately depict each road segment,

associated feature, or characteristic landscape type. Site

plans, measured drawings, and sketches can document

road alignments, cross sections, construction details for

pavements, guard walls and other engineered elements,

along with roadside landscape characteristics and contributing features such as signs, pullouts, bridges, and

entrance stations. Deviations from historic conditions

should be noted and problem areas described in both

graphic and narrative form. Since the length of most park

roads precludes precise mapping of the entire road

corridor, an effective strategy is to articulate representative roadway cross-sections and character-defining

landscape views while reserving measured drawings for

significant subcomponents and contributing features.

Examples of this type of graphic documentation can be

found in America’s Park Roads and Parkways: Drawings

from the Historic American Engineering Record.

Photographic documentation plays an essential role in the

existing conditions survey. Key features should be

photographed to document character-defining details and

depict their overall contributions to the historic road

landscape. Since park tour roads were intended to

provide calculated visual experiences, photographs should

capture the motorist’s perspective along with planned

views from associated scenic lookouts. Videography can
HISTORIC ROADS 23

Systems (GIS) and GPS can be useful in documenting

historic road features and presenting the results of both

historical and existing condition research. With GIS

technology, many kinds of data can be linked together,

including photographs, drawings, databases, and textual

descriptions. This information can then be manipulated

to illustrate original development patterns, subsequent

alterations, existing conditions, and proposed treatment

plans.

The end result of the existing conditions documentation

phase should be a precise, detailed, and accurate record

of the historic road’s current physical status. This graphic

and narrative record should be annotated to denote

alterations that have occurred since the road was

be a useful research tool, and sequenced stills might be

incorporated into the CLR to demonstrate visual

progressions and scenic variation. Both digital and

traditional photographic technologies can be employed.

Consideration should be given to using color media,

especially when documenting the ways in which historic

road-builders attempted to harmonize structures with

native landscapes. For practical reasons, however, most

CLRs will be printed in black and white.

Geographic Position System (GPS) units, measuring

wheels, and digital measuring devices are useful in

calculating distances and defining the precise locations of

documented features. Computer technology, including

Computer-Aided Design (CAD), Geographic Information

Figure 19. Documentation of significant road feature on Sequoia National Park’s Generals Highway, showing general location, plan,

section, interpretive view, and historic alignment changes. (HAER 1993)
24 L A N D S C A P E L I N E S

completed and/or after the conclusion of revisions

undertaken during its designated period of significance.

Whether these changes were the result of natural

processes, intentional actions, or unplanned activities, the

existing condition survey will serve as the basis for

evaluations of historic integrity and the development of

cultural landscape treatment plans. Deviations from

original conditions should be clearly noted on a feature by

feature basis as well as for the overall resource.

A Guide to Cultural Landscape Reports provides additional information on existing condition survey formats

and terminology. Sidebar 3 provides suggestions for

evaluating historic park roads through the CLR’s standard framework of thirteen landscape characteristics.

Rigid applications of these taxonomies are not mandatory, however, and the existing condition survey should

employ terms and categories that are bested suited to

the resource under examination.

SIDEBAR 3: EVALUATION OF LANDSCAPE CHARACTERISTICS FOR ROADS

Natural Systems and Features

Summarize the natural systems (geomorphology, geology, hydrology, ecology, climate, vegetation, etc.) that influenced road

development and the physical form of the road corridor.

• Describe the broad natural character of the region or regions through which the road passes (alpine, desert, rain forest, coastal,

etc.) and discuss the impact of these characteristics on design, construction, and experience (deserts or rocky terrain will produce a

different landscape character and require different engineering measures than a temperate alluvial plain or region of rolling hills, etc.)

• Identify any distinctive natural features that affect the road’s location and disposition (the desire to showcase an attractive lake or

peak, the need to take advantage of a mountain pass or cross a canyon or river, the presence of other natural attractions or

obstacles,etc.)

• Discuss how local climatic concerns or other natural processes influenced the road’s development and evolution (the need to

accommodate excessive water-runoff, for instance, or the conscious arrangement of roads and vegetation to facilitate snow melt)

• This should be done at the macro scale of the road’s general location and the micro scale of the design and location of individual

features and roadway segments

Spatial Organization

Describe the three-dimensional organization of the road corridor’s physical forms, emphasizing the ways in which these

characteristics define the spatial and visual character of the roadway landscape

• Document the road’s current location and identify historic alignments that may have been altered, bypassed or abandoned 

• Determine the boundaries that will be used for CLR purposes (generally this will be a corridor including the road surface, shoulders,

and all bordering areas that bear evidence of grading, planting, and other interventions; boundaries may also include contiguous

viewsheds and their logical physical limits; scenic pullouts, waysides, and roadside service areas should be included; associated

campgrounds and visitor facilities may be included in the park road’s boundaries or considered independently, depending on their

scope and development history; in some cases, especially with parkways, a historic park road’s boundaries may coincide with NPS

property lines)

• Distant views and landmarks should be identified and analyzed for their impact on the roadway’s location, design, and visual experience, but generally should not be included within the boundaries of the historic road CLR

• Document the road in terms of plan, profile and section, demonstrating how the alignment and roadway prism shape the physical and

experiential character of the park road landscape: describe the character and frequency of the road’s curves and straightaways

(tangents); describe the nature and extent of grades: is the road primarily flat or hilly? Is the profile consistent, gently undulating,

bumpy and irregular? Document the dimensions and character of the road prism, including travel surface, shoulders, side slopes and

treeline

• Since most park roads exhibit considerable variation in spatial character and geometry, it is often desirable to identify representative

roadway segments and document their distinguishing characteristics in terms of plan, profile, section, and overall experience

• Identify changes that have occurred since the original design or period of significance

• Any horizontal expansion of the travel surface, shoulders, or roadside clear zone should be carefully noted; changes in profile and

alignment should also be closely monitored

• Speed, scale, and sight distance are crucial elements of a park road’s spatial organization; changes in any of these variables should be

carefully noted, since they can have exponential impacts on the experiential character of park road landscapes
HISTORIC ROADS 25

Land Use

Describe the patterns of human activity that have influenced the landscape of the road corridor

• Typical land uses might include agriculture, logging, mining, and recreation; if present, identify the nature, appearance, and social and

ecological impacts of these activities

• Park-related land uses should also be considered, including passive and active recreation, commemoration, historic preservation,

interpretation, parking, lodging, maintenance, and administration

• Describe any current or historic management activities aimed at retaining, restoring, or remediating the impact of land uses (such as

agricultural leases, concessions, mowing, and revegetation)

• Land uses that occur beyond park boundaries should be described if they are visible from the road or associated viewpoints; changes

between historic and contemporary views should be noted, along with any broad trends or specific developments that will impact

historic viewsheds; scenic easements and other existing or proposed viewshed management practices should be described

Cultural Traditions

Identify practices of construction, design, and use associated with cultural traditions and ethnographic groups that influenced the development of the road corridor. These may include:

• Historic, prehistoric, ethnographic or vernacular sites, structures, and artifacts that influenced the road’s location and overall design

• Historic, prehistoric, ethnographic or vernacular building practices that provided design cues for the park road landscape (typical

examples include “vernacular” split rail fences, “Appalachian-style” visitor facilities, and “adobe” walls, signs, and structures; Colonial

Parkway’s rough-aggregate concrete pavement designed to mimic historic marl roads is an exceptional example of road-builders

intentionally evoking local traditions; Colonial Revival elements could be categorized as reflections of cultural traditions, as could

explicitly “Modern” materials and motifs)

• The influence of historic tourist practices should also be considered in this category: tourist practices can influence the location,

alignment, design, and materials of park roads. For example, roads designed to be enjoyed from small vehicles at slow speeds by

visitors on extended vacations will exhibit different characteristics than roads designed to be experienced at higher speeds by

visitors on more compressed schedules; the frequency, location, and design of lodgings and other visitor facilities will also reflect

historical tourist practices

• Evolving cultural traditions also affected the location and content of roadside interpretation, which became more extensive as guided

tours gave way to independent motor travel; the emphasis of interpretive texts may vary from the celebration of scenic wonders to

folksy history to more rigorously interpreted ecological and cultural information

Cluster Arrangement

Describe the location of buildings, structures, and support facilities along the road corridor and identify the patterns that

govern their placement 

• Identify the historic and current location of structures, pullouts, parking lots, campgrounds, individual campsites, etc

• Describe the relationship between these facilities and the ordering principles that determined their layout, identifying variations that

may reflect different eras or development strategies

Circulation

Since a park road is, by definition, a circulation element, the emphasis should be on identifying the ways in which it

accommodates basic circulation functions and the individual road or road segment’s relationship to broader park-wide or

even regional circulation networks

• If the road or roads predated park development, describe historic circulation function(s)

• Describe the basic circulation function the road is intended to perform in the park (does it connect scenic features, recreational

features, historic sites, administrative elements, etc? — or combinations thereof?)

• Describe the road’s relationship to other roads within the park or surrounding area, both in general terms and in regard to

intersection locations and designs (noting any changes that have occurred)

• Describe the road’s relationship to other circulation systems such as sidewalks, foot paths, bridle trails, boat launches, maintenance

networks, fire roads, etc.· Identify seasonal variations in circulation, such as the influence of snowfall, rainy periods, visitation

patterns associated with natural cycles like foliage or cultural factors such as holidays and special events

• If more than one road is being examined, articulate the relationships between the various segments, identifying historic and contemporary travel patterns, hierarchies of use, interpretation, or management
26 L A N D S C A P E L I N E S

• Identify major changes that have occurred to the circulation system, including full or partial closures, bypasses, changes between oneand two-way traffic, the addition of multiple lanes, the impact of new roads, bridges, tunnels or other developments altering historic

travel patterns or design concerns, etc.

• Describe relevant external influences on the park road’s circulation functions, such as increased or decreased traffic loads due to

surrounding development or road construction

• Identify other impacts on the road’s circulatory function, such as changing vehicle standards, visitation numbers, and usage patterns

Topography

Detail how the road relates to specific topographical conditions

• How is the road located in response to topographic features such hills, valleys, ridges, passes, ravines, lakes, watercourses, etc?

• How do the location and design of the roadway reveal, conceal, and/or showcase topographic features (and how are these techniques sequenced for varied scenic effects?) 

• How does the horizontal and vertical alignment (plan and profile) relate to topographical conditions? Does the road climb steeply or

gradually? With many switchbacks or fewer longer curves? Where and how are curves located? Does the road generally follow

natural contours, winding around obstacles, or does it slice through the terrain on notable cuts and fills? How else does the basic

topography affect the design and experience of the roadway? Does the topography necessitate bridges, viaducts, retaining walls,

guardwalls, etc?

• When cuts and fills are necessary, are the slide slopes harmonized with the natural topography or are disturbances to the natural

topography plainly evident? If rock ledges were cut, is this obvious or were the cut surfaces “naturalized” by concealing drill marks,

coloring, etc?

• How are scenic pullouts, parking areas and other associated features sited in relationship to topography?

Vegetation

Characterize the roadside vegetation and its impact on the road’s development and visual character

• Describe the basic massing and character of the existing vegetation; identify both general patterns and individual species

• Describe the ways in which designers placed the roadway and manipulated the character and massing of surrounding vegetation help

define the park road experience, paying particular attention to the ways in which designers manipulated these elements through

planting, clearing, trimming and other techniques 

• Distinguish between indigenous and non-native species, noting whether non-native species were associated with road’s development

or pre-existing land uses, or reflect post-development processes

• Try to distinguish between vegetation that was present during the period of significance and subsequent alterations stemming either

from natural processes or management policies: have historic views been occluded, clearings grown in, or treelines moved forward

or back?

• Determine the health of the vegetation: have disease, invasive species or other influences affected the health of the vegetation?

• Identify changes and threats to vegetation that may not be contiguous but plays a significant role in constituting the view from the

road

Buildings and Structures

Identify the location, character, and basic dimensions of buildings and major structures found along the roadway, including:

• Engineering structures such as bridges, viaducts, retaining walls and other slope stabilization devices, guardwalls, guard rails, and

drainage features including culverts, culvert headwalls, and gutters

• Park-related constructions such as entrance stations, entrance arches, wayside kiosks and other interpretive facilities, comfort

stations, visitor centers, administrative buildings and maintenance facilities

• Pre-existing resources such as historic buildings and agricultural structures, statues, and monuments

• For each building or structure, briefly note its condition and impact on the park road landscape
HISTORIC ROADS 27

Views and Vistas

Describe the views and vistas that collectively comprise the park road’s scenic character

• Describe the general view of and from the road, which may exhibit considerable variation: what does the roadside scenery consist

of? Are vegetation and other objects close to the travel surface, distant, at various distances? Is there a general sense of enclosure,

openness, exposure, variation? Are there notable sequences? Does the road provide sweeping panoramic vistas, occasional

glimpses of scenic attractions, intimate proximity to natural or historic features, etc? How do the road and associated features

contribute to the landscape experience? How are all these impressions created through combinations of road design, topography,

and vegetation?

• Identify designed views and vistas intended to showcase exceptional scenery, either from a stationary position such as a pullout or

overlook, or displayed in motion as highlighted through axial alignments, curves or other design elements; describe both the nature

of the scenery and the techniques used to display it

• Identify and describe view-framing devices such as vista-cutting, canopy views, and tunnel portals or adets

• Determine if changes in vegetation have impacted intended views and vistas (either by obscuring planned views or by opening up new

ones)

• Determine if changing land uses or other factors have altered views, either within the study area, the broader park, or the surrounding locale

• Identify general trends or specific projects that may impact park road viewsheds

Constructed Water Features

Identify constructed water features that contribute to the park road landscape

• Describe the location and character of dams, canals, constructed waterfalls, ponds, or reservoirs that are constituents of the park

road landscape

• Identify instances in which stream courses and other “natural” water features have been manipulated to enhance the appearance or

function of the park road corridor

• Describe changes that have occurred since the road’s development, either through natural processes or managerial actions

Small-scale Features

Document the location, character, age, and condition of small-scale features that contribute to the appearance and/or

pragmatic function of the park road landscape, which may include

• Park development-related features such as road signs, interpretive signs, other directional and administrative signage, fences, water

fountains, watering stations for horses or automobiles, curbs, lane-striping, reflectors, picnic tables, benches, trash receptacles, etc.

• Pre-park development-era features such as historic fences, monuments, tablets, and displays; vernacular landscape features such as

stonewalls or other agricultural relics; other small-scale features reflective of previous land uses

Archeological Sites

The CLR survey should note the location and condition of known surface and subsurface sites of prehistoric and historic

activities within the road corridor or associated with the historic road, including

• Prehistoric sites such as Native American architecture, mounds, trails, and other sites

• Historic sites and structures related to specific events such as battles, migrations, encampments, celebrations, etc

• Historic roads and related structures pre-dating park development

• Historic sites and structures related to pre-park activities such as settlement, agricultural, logging, mining, and transportation

(including trails, railroads, and canals)

• Historic sites and artifacts related to park roads and associated developments, including: overlaid pavements and associated road

features directly within the current road prism; archeological evidence of former plantings or landscape management practices;

abandoned road segments and fragments (such as travel surfaces, ditches, culverts, curbing, retaining walls, guardwalls, etc.);

abandoned bridges, bridge abutments, and fragments; road construction or maintenance camps and facilities; quarries and borrow

pits; travel-related sites and artifacts such as parking areas, campsites, food & lodging concessions, gas stations, stagecoach loading

platforms, etc. (most of these associated facilities should be noted in brief unless they are either within the road corridor or

contribute strongly to its significance)
28 L A N D S C A P E L I N E S

ANALYSIS AND EVALUATION

This component of the CLR compares existing resources to historical conditions in order to assess the

integrity of historic park roads and related resources,

establish their significance, and identify principle preservation concerns.

This procedure involves articulating the park road’s

significance, identifying aspects of the park road landscape that define its historic character, and then evaluating the current condition of the resource to determine

whether or not it possesses sufficient integrity to convey

its historic character and significance. This process is an

important step toward developing specific treatment

plans and broader stewardship policies.

The analysis and evaluation section begins by establishing the road’s significance in relation to broader themes

in American history. While the general historical

section traces the road’s entire evolution in considerable detail, this component takes a more selective and

analytical approach, identifying the most important

aspects of the road’s design, use, and development.

The basic approach for making determinations of

significance is outlined in the National Register bulletin

How to Apply the National Register Criteria for Evaluation. Additional guidance in applying National Register

criteria to cultural landscapes can be found in the

National Register bulletins How to Evaluate Historic

Designed Landscapes and Guidelines for Evaluating and

Documenting Rural Historic Landscapes.

Park roads are most likely to qualify under the National

Register Criteria A: Association with events that have

made a significant contribution to the broad patterns of

our past; and/or C: Design/ Construction. Other

criteria may also contribute to a park road’s significance.

A significant designer or administrator may have been

associated with its development, for instance, or an

important figure may have had some relationship to the

site, making it eligible under Criterion B. For road’s

predating park development, significance may be

associated with historical patterns of migration or

commerce, or with a specific event such as a military

engagement, political action, or cultural event. Many

roads are likely to be eligible under several categories

and should be evaluated accordingly. The ways in

which the road embodies these criteria should be

clearly demonstrated, along with the road’s relationship

to recognized contexts and theme studies.

The National Register and the NPS Park History

Program have identified a broad array of historic themes

and developed detailed context studies for many of

them. Contexts and areas of significance that may

prove useful for evaluating park roads include: Architecture, (especially “NPS Rustic Architecture”), Community Planning and Development, Conservation, Engineering, Entertainment/Recreation, Landscape Architecture (see context studies on “Landscape Architecture in

the NPS, 1916-1941), Politics/Government, Social

History, and Transportation. Sidebar 4 highlights

several National Register nominations that demonstrate

various approaches to the evaluation and registration of

historic park road resources.

It is important to remember that a road need not

possess national significance in order to be eligible for

the National Register. Many park roads have considerable significance at the state or local level. If a historic

road is a representative example of its type within a

park, NPS region, or state, it may merit listing in the

National Register and concomitant attention in the CLR.

Establishing the period of significance is a critical aspect

of the evaluation process. Periods of significance should

reflect historically-based dates of development or use,

rather than arbitrary applications of the National

Register’s fifty-year eligibility standard. The “fifty-year

rule” is not an absolute cut-off date, moreover. Consideration can be given for newer roads and related

features of exceptional significance. If the majority of a

road’s resources were constructed more than fifty years

prior to the evaluation, there is no need to demonstrate

exceptional significance for contributing features from a

later period as long as it represents a continuum of the

historical development scheme. CLR preparation

should also consider the prospects of roads that are

approaching the fifty-year threshold. Many Mission 66-

era park roads will soon be reaching the point of

potential eligibility and CLRs should be developed with

this fact in mind.
HISTORIC ROADS 29

After identifying the context and period of a park road’s

significance, the next step is to delineate its characterdefining features. Not all existing features are likely to be

historic, nor will all historic elements necessarily qualify as

character-defining features. Character-defining features

are those aspects of a historic resource that are essential

for conveying its identity and significance. In the case of

historic park roads, character-defining features might

include engineering factors such as pavement width,

composition, curvature, and cross-section; structural

elements such as bridges, culverts, signs, and guardwalls;

broader landscape considerations such as vegetation,

grading, roadside views, and designed vistas; and cultural

associations or social practices such as motor tourism,

auto-camping, public history, and commemoration.

Since road design standards change over time and

landscape components may have been added or

modified for various reasons, it is necessary to identify the

features that defined the park road experience during the

period of significance. Their historic characteristics and

contributions to the overall park road landscape should

be described in detail. Saying that a road “lies lightly on

the land” or exhibits “naturalistic design” is not sufficient:

specific dimensions, design techniques, materials, and

landscape experiences should be articulated as precisely

as possible. Subsequent deviations from historic standards should be carefully noted, along with the addition

or removal of landscape elements. These determinations are essential for distinguishing between contributing

and non-contributing features, assessing condition, and

evaluating the overall integrity of park road landscapes.

Seemingly minor variations in alignment, width, design

speed, and vegetation management patterns can dramatically alter the character and integrity of historic park

roads.

The National Register defines integrity as the ability of a

resource to convey it historic significance. While integrity

is often related to physical condition, the two terms are

not synonymous. A resource may be in good condition

from a maintenance standpoint, yet have little historic

integrity, whereas a resource with high historic integrity

may appear deficient from a purely functional standpoint.

This distinction is particularly important for historic road

evaluation, because measures intended to improve

practical performance frequently compromise historic

fabric and experiential character. This dichotomy should

be kept in mind when interpreting materials that apply

modern engineering standards to historic park road

resources. In these documents, aspects of a road that the

CLR might characterize as essential to its significance and

integrity are often cited as technical problems in need of

remediation. Technically-oriented condition analysis plays

a role in the development of CLR treatment proposals,

but the analysis and evaluation phase focuses on determining historic integrity as defined by National Register

principles rather than by conformance to modern

engineering standards.

In order to have integrity by National Register standards,

a resource must retain sufficient physical evidence of its

appearance during the period of significance for visitors to

understand its historical character and significance. The

National Register has identified seven qualities that must

be evaluated in order to assess the integrity of a historic

resource: location, design, setting, materials, workmanship, feeling, and association. Guidelines for applying

these criteria to historic resources and cultural landscapes

in general can be found in the previously cited National

Register bulletins. The following paragraphs provide

more specific guidance for evaluating the integrity of

historic park roads.

Location is a Location fundamental aspect of a park road’s

integrity. To possess integrity a park road should

generally occupy its original location, following the same

route and providing access to the same sights and

experiences that prevailed during the period of significance. While original location is a key concern, minor

variations may be permissible, especially when they do

not markedly alter the general park road experience. A

modest relocation that carries the traveler through

essentially the same terrain and maintains a similar

relationship to the surrounding landscape might be

allowable, as might minor reconfigurations of intersections or realignments of short road segments, unless the

intersections or individual sections themselves are

deemed inherently significant. Greater latitude should be

allowed for lengthy park roads extending through

relatively undifferentiated terrain than for comprehensively designed parkways where all aspects of location,

alignment, and surrounding landscape development were

more precisely planned and controlled.
30 L A N D S C A P E L I N E S

social practices like logging, mining, or residential

development, all of which can dramatically impact the

view from the road. The cessation of traditional

farming practices can adversely affect the setting of park

roads intended to showcase agricultural heritage.

Integrity may also be compromised if a road’s significance is tied to its role in providing access to natural

sites or cultural features that have been significantly

altered or are no longer used according to historic

patterns.

Materials Materials Materials clearly play a prominent role in establishing a

park road’s appearance and communicating its historical

character. Assessing the degree to which the repair or

replacement of original construction materials impairs a

park road’s integrity can create difficult judgments. Most

park roads have been periodically resurfaced, so as long

as the new surface retains the historic character (similar

color, texture and basic composition), replacement

should probably be condoned. The issue becomes

more complex when evaluating masonry features such

as guardwalls, gutters, curbs, and retaining walls.

Modest repairs are usually unavoidable, but new

materials and patterns should closely resemble historic

fabric. Large-scale reconstructions and rehabilitations

require careful consideration, especially when materials

such as simulated stone are employed or the height,

pattern, or coloration of the masonry is changed. The

overall impact on the park road experience should be

the determining factor. The relative significance of the

feature should also be weighed. For roads where

masonry guardwalls or traditional rail fencing contribute

strongly to historic significance and character, material

changes may have more profound effects on integrity

than for roads where such features play less prominent

roles. While vegetative materials clearly have finite

lifespans, general massing and species composition

should be consistent with historically significant conditions. Since vegetation is a dynamic resource, reasonable allowance should be made for natural evolutionary

processes, which may have been envisioned by the

original designers. The occlusion of planned vistas,

encroachment of open spaces, and presence of invasive

species are sources of concern, though these conditions

can often be remedied through treatment.

Design incorporates the Design entire corpus of engineering,

architectural, and landscape architectural techniques that

establish a road’s physical structure and experiential

character, from the technical and aesthetic attributes of

individual components to the appearance of distinctive

sections to the general character of the park road as a

whole. Key concerns include alignment, plan, crosssection, landscape design, and associated features, both

large and small. It is important to consider both the

condition of individual elements and the overall appearance of the park road landscape. All aspects of the

road’s designed landscape should be evaluated for

conformance to historical appearances. Since concepts

such as “NPS Rustic” or “Naturalistic Design” exhibited

considerable regional and temporal variation, evaluation

criteria should be location-based and time-specific.

Selective alterations to individual components do not

necessarily impair the integrity of the park road as a

whole, but the overall impression produced by the park

road’s design should remain consistent with historical

precedents. While technological upgrades can be

accomplished in a context-sensitive manner, the

cumulative effect of seemingly minor alterations in

alignment, pavement width, guardwall height, and

roadside grading and landscaping can severely compromise a park road’s historic integrity. Strict conformance

with historical appearances will be more important for

parkways and other comprehensively designed roads

nominated under Criteria C than for roads whose

significance rests primarily in their association with

historical events or their relationships to more general

social patterns or processes.

Setting Setting encompasses both the immediate roadside

corridor and the broader environment visible from the

travelway or associated viewpoints. While evaluation of

the immediate roadway environment is closely related

to the assessment of design, setting also applies to less

overtly manipulated roadsides, whose character may be

established by natural processes, agriculture, or other

social practices. Historic photographs or written

descriptions can often be consulted to evaluate the

degree to which contemporary roadsides convey

historical conditions. Setting also refers to the roads’

relationship to broader landforms, landscapes, and

cultural features. Integrity of setting can be compromised by natural processes such as floods or fires, or by
HISTORIC ROADS 31

Workmanship, or Workmanship the visible evidence of group or

individual craftsmanship, is another factor in evaluating

the integrity of park roads. While most roads were

produced through mechanized processes, traditional

craftsmanship values were expressed in the construction

of associated features such as guard walls, guard rails,

culvert headwalls, signs, and other timber and masonry

accouterments – much of which represents the

historically significant handiwork of CCC enrollees.

Replacing original hand-built features with massproduced materials such as steel beams or simulated

stone can seriously degrade the integrity of component

resources and the park road as a whole. Even when

hand labor is employed, deviations from historic

masonry patterns and the use of rectilinear dimensioned

lumber rather than hand-shaped timbers can have an

adverse effect. On a more subtle level, modern grading

practices can produce a cruder and more mechanistic

appearance than was historically achieved through hand

labor. Replacing slightly irregular field-based alignments

with scientifically calculated curvature could also be seen

as diminishing evidence of historic construction techniques and workmanship.

Feeling is a critical Feeling factor in evaluating the integrity

historic park roads. In order to possess integrity of

feeling, existing physical features must convey the road’s

historically significant character. While some modifications to original materials, workmanship, and location

are permissible and perhaps inevitable, the overall

impression conveyed by the park road landscape should

enable modern viewers to partake in the same sensations that defined the park road experience during the

period of significance. Since the park road experience is

a dynamic impression produced by a complex combination of factors, the cumulative impact of incremental

changes and seemingly minor alterations must be

closely scrutinized. Speed and scale are important

variables to consider along with more obvious changes

to vegetation and constructed features. Studies have

shown that minor increases in the width of the pavement, road prism, and rate of travel dramatically impact

perceptions of the surrounding landscape. The traditional park road experience of winding slowly along a

narrow pavement in close proximity to natural features

is significantly compromised when speeds increase and

the pavement or surrounding clear zone is perceptibly

widened. If the park road’s significance is tied to a

specific period, design standard, and mode of experience, the historic impression as interpreted from plans,

photographs, and contemporary accounts should form

the basis of evaluation; the fact that a modernized park

road follows a more or less historic alignment and is

more attractively configured than a contemporary

highway is not sufficient grounds to ascribe integrity of

feeling.

Association, or Association the ability of a historic resource to

provide a mental link to a historic event, period, or

person, is a more abstract quality, but it also requires

the presence of physical attributes that retain the ability

to evoke past experiences. Location and setting may be

more significant in this regard than materials and specific

design attributes, but existing features must still communicate the essential character of the road’s historic

identity. Both the nature of the road’s significance and

the condition of character-defining features should be

considered. A historic alignment may allow contemporary motorists to trace the same route as earlier visitors,

but a high-speed modernized roadway flanked by

imposing safety barriers and broad clear zones may not

evoke the sense of adventure and accomplishment

associated with early park travel. A reinforced concrete

simulated-stone guardwall may be more attractive than

a jersey barrier or steel w-beam, but it would be a

stretch to claim that it conveys associations of traditional

rustic construction practices or CCC-era social history.

As with the evaluation of feeling, the overall impression

afforded by the park road landscape, rather than the

status of individual features, should guide the ultimate

determination.

A historic road need not demonstrate integrity in every

aspect to merit an overall positive evalution. The

relative importance of the various aspects will depend

on the nature of the roadway and its identified significance. A road that is listed primarily for its design and

construction would be expected to exhibit considerable

continuity in form, materials, and workmanship, while

the integrity of a road that is linked to a specific event or

individual may be evaluated more in terms of its

location, setting, association, and feeling. It is important

to remember that the feelings and associations generated by historic sites and locations are never enough to
32 L A N D S C A P E L I N E S

justify a positive determination of integrity on their own:

tangible physical evidence of a road’s historic character

must be present and readily visible in the contemporary

landscape.

The National Register process also calls for the identification of contributing and non-contributing features.

While this terminology is less critical for the CLR, the

concept is useful for evaluating integrity and developing

treatment plans. Generally speaking, aspects of the park

road landscape that have been significantly altered or

postdate the period of significance will not be considered contributing features, nor will period-correct

elements that do not play significant roles in defining the

resource’s essential historic character. In some cases,

historic features may have lost their individual integrity

yet continue to play important roles in sustaining the

overall character of the park road resource. A replacement guard wall, for instance, would possess no

integrity of its own, but if it were reproduced convincingly, it could contribute to the overall historic appearance of the roadway. Landscape elements that have

lost their historic character may also be returned to

contributing status through remedial efforts outlined in

the treatment section. Historic views could be

reopened through selective cutting, original vegetation

could be replanted, and various structural elements can

be returned to their historic appearance. Where

alterations are significant and irreversible, it may be

necessary to designate entire sections of a road as noncontributing. This approach should be used sparingly,

and only in situations where the broader park road

landscape retains sufficient integrity to provide a strong

sense of its historic character and identity.

While National Register guidelines should form the

basis of the evaluations of significance and integrity, the

CLR is not meant as a substitute for a National Register

nomination or Determination of Eligibility (DOE). The

CLR can build on or help to amend pre-existing

nominations. When a DOE or nomination does not

already exist, the research, documentation, and analysis

conducted for the CLR can play an invaluable role in

developing a formal submission. The CLR team should

consult park and regional cultural resource specialists,

National Register personnel, and State Historic Preservation Office staff to determine whether or not this

would be a desirable course of action and then work

closely with these experts to share research findings and

collaborate in the preparation of any resultant DOEs or

National Register nominations.

While the CLR analysis and evaluation process can assist

in the preparation of National Register nominations and

DOEs, its primary purpose is to identify resource

management needs and set priorities for subsequent

treatment plans. Understanding the significance,

condition, and integrity of historic park road resources is

a fundamental step in developing appropriate preservation plans and stewardship policies. The process for

moving from research and analysis to the development

of specific treatment recommendations is covered in

the following section of this Landscape Line.

HISTORIC PARK ROAD TREATMENT

The treatment section of a historic road CLR builds on

the research and analysis phases to produce a comprehensive park road stewardship strategy. The goal of the

treatment plan is to retain the historically significant

qualities of the park road, or, if necessary, to devise a

program for returning the road and/or its component

features to historically accurate conditions. The

treatment plan must consider contemporary management concerns along with changing physical and

technical factors, and may require innovative solutions

to reconcile modern challenges with historical imperatives. It also needs to be sustainable, both environmentally and economically. Resource availability must be

considered when proposing treatments that require

significant initial outlays, long-term maintenance

commitments, or unusual materials or technical

expertise. The plan should articulate general policy

goals, provide specific guidelines for the treatment and

management of significant cultural resources, and

propose measures for documenting treatment actions

and evaluating their short and long term impacts.

The treatment plan should be devised in consultation

with park staff and representatives from the various

agencies involved in park road management. While all

cultural resource specialists work within an ever-
HISTORIC ROADS 33

SIDEBAR 4: EXAMPLES OF ROADS LISTED ON THE NATIONAL REGISTER OR AS NATIONAL

HISTORIC LANDMARKS

Glacier National Park’s Going-to-the-Sun Road was listed on the National Register in 1983. Since this was a relatively

early park road nomination, the resource was categorized as a structure and the nomination emphasized engineered

features such as bridges and tunnels, with limited reference to broader landscape characteristics. Boundaries were set at

15’ on either side of the center line. The listed area amounted to just over 177 acres, stretching 48.7 miles from the

eastern park boundary to an intersection several miles from the western boundary that represented a significant change in

the historic location. The road was listed under the themes of engineering and park development, with a period of

significance reflecting the original planning, design, and construction dates of 1921-1933. In 1997 the Going-to-the-Sun

Road was designated a National Historic Landmark District. The NHL registration expanded the boundaries to 30’ on

either side of the center line and extended the period of significance to 1952, when the road was fully paved with bituminous concrete. The road was listed under NHL Criteria 1 & 4 and National Register Criteria A & C, with significance in

landscape architecture, transportation, and politics. Greater emphasis was placed on broader landscape, planning and

design concerns. The original width and alignment of the road were cited as retaining a high degree of integrity, along with

the bridges, tunnels, substantial portions of the guardwalls, and the surrounding views and vegetation.

The 1987 National Register nomination Multiple Resources for Zion National Park included several roads and roadrelated features. The Zion-Mt. Carmel Highway (1926-1930) was listed as a contributing site with four major contributing

resources: Zion-Mt. Carmel Highway Tunnel, Zion-Mt. Carmel Highway Switchbacks, Virgin River Bridge, and Pine Creek

Bridge. Entrance signs, comfort stations, and the East Entrance Checking Station were listed as individual buildings.

National Register Criteria A & C provided the basis of the road-related listings, for which the themes of landscape architecture, transportation, and NPS Rustic Style were invoked. A detailed addendum supported the 1996 listing of the scenic

Floor of the Valley Road (1932-1942), which had been excluded earlier on the grounds that it lacked the engineering

distinction of the Zion-Mt. Carmel Highway. The red-tinted pavement and native sandstone masonry were identified as

character-defining features and retaining walls, drainage features, parking areas, and viewpoints were documented as

contributing resources.

Shenandoah National Park’s Skyline Drive was listed as a National Register Historic District in 1997. The extensively

documented nomination supported its significance under Criteria A and C, emphasizing the areas of landscape architecture, transportation, social history, recreation, politics, engineering, conservation, and community planning and development. The 1931-1951 period of significance encompassed the drive’s original planning and construction, along with

important subsequent modifications prior to Mission 66. The drive’s topography, vegetation, engineering, architecture,

landscape design, and associated features were described at length. Recently reconstructed concrete-core guardwalls with

hand-laid stone veneer created by splitting the original rockwork were deemed not to compromise the drive’s historic

integrity, despite their greater height and length and the switch from dry-laid to mortared construction.

Colonial Parkway, the primary circulation system of Colonial National Historical Park, was listed as a National Register

Historic District in 2001, under Criteria A and C, with a period of significance stretching from 1930-1958. The latter date

reflected the completion of final aspects of the parkway’s development. Since primary development occurred during the

1930s, no exception was deemed necessary to qualify it as a resource achieving significance in less than fifty years. Colonial Parkway’s significance rests in its role as an embodiment of park development and recreational trends of its period and

in its status as an exceptionally intact example of 1930s landscape architecture and parkway design. Both the roadway

itself and the broader parkway landscape were judged to possess a high degree of integrity. While several new gradeseparation structures have been added, their massing and brick veneer harmonized with historic design standards. Bridge

and pavement reconstructions similarly upheld traditional patterns. The Colonial Parkway nomination is an excellent

illustration of a comprehensive landscape-based approach to park road documentation and evaluation.

The Natchez Trace Parkway in Mississippi contains several listed sections of the Old Natchez Trace, demonstrating the

manner in which road-related sites predating NPS development have been recognized for their historic significance. A

portion of the old trace in Madison County near the site of one of the earliest inns along the route was listed in 1976 for its

significance in the areas of transportation, communication, and education. Another Madison County section including the

Old Natchez Trace and Choctaw Agency Site, was listed in 1994. Of the 3.3 miles listed segment, which is distinguished by the remains of a 30’-wide surface that is occasionally sunken between high earthen banks, 1.4 miles are within

parkway boundaries. This segment qualified for listing under Criteria A & D, on the grounds that the unpaved sunken

roadway and overhanging vegetation evoke strong associations of the Old Natchez Trace, while both the Choctaw Agency

site and the trace itself contain significant archeological resources. 
34 L A N D S C A P E L I N E S

expanding matrix of regulations, policies, and programmatic concerns, historic park road stewardship is further

complicated by the array of agencies, authorities, and

legal, technical, aesthetic, and ecological issues involved.

In addition to complying with NPS planning regulations,

General Management Plan prerogatives, and federal

preservation and environmental protection laws,

historic road CLRs must address the technical standards,

policies, and protocols that inform contemporary

highway engineering practice. This is particularly

important in the treatment section of the CLR, where

proposals must take into consideration national highway

design standards along with the practical concerns and

procedural requirements of the NPS Park Road

Program (PRP) and its partners in the Federal Highway

Administration’s (FHWA) Federal Lands Highway

Program (FLHP).

PRP staff and the regional FLHP coordinator should

be closely consulted when developing the treatment

component of the CLR. In addition to serving as

liaisons with FHWA staff who will play a major role

in implementing road projects, they can provide

important guidance on technical and administrative

matters, particularly in regard to coordinating CLR

recommendations with PRP activities and published

design standards.

Park Road Standards

The NPS has articulated its approach to park road

design and management in a series of technical and

administrative briefs dating back to the service’s inception. The 1984 NPS Park Road Standards bulletin is

the most recent publication in this series and should

serve as the starting point for considerations of contemporary perspectives on design, function, and safety

concerns. While the design specifications provided in

the 1984 Park Road Standards adhere closely to general

federal standards, the publication emphasizes that park

roads are unique environments intended for leisurely

recreational travel. Preserving the quality of the park

road experience is an explicitly stated goal. When

accommodating current or projected demands would

entail measures that might compromise a park road’s

unique qualities, Park Road Standards recommends

adopting policies to control incompatible uses. The

CLR can call attention to these published policy goals to

help make the case for context-sensitive park road

stewardship.

While Park Road Standards promotes flexibility over the

rigid application of formulaic technical criteria, the

influence of such standards remains pervasive. The

principal source of standards for road development in

the United States is the American Association of State

Highway and Transportation Officials’ A Policy on

Geometric Design of Highways and Streets. Commonly

known as the AASHTO Green Book, this publication

provides specifications, or “AASHTO standards,” for

virtually every aspect of road construction, from

pavement width, curvature, and sight distance to

guardwall location, height, and composition. While

AASHTO standards are legally binding only for roads

within the officially designated federal highway system

(or where otherwise adopted by the governing agency),

the Green Book’s depth, breadth, and rigorously tested

technical data make it the primary reference for highway

engineers and transportation planners engaged in roadbuilding and rehabilitation activities throughout the

country. AASHTO’s Roadside Design Guide provides

additional information on roadside safety treatments,

with extensive details on safety barriers, clear zones, and

related matters that bear directly on park road management.

In proposing treatments for historic park roads, it is

important to recognize that the solutions called for in

modern engineering publications are not always

compatible with efforts to maintain or restore historic

integrity. The potential for conflict between historic

values and contemporary technical criteria is greatest

when applying standards prepared for modern highway

construction to historic roads designed for different eras,

different purposes, and different technical constraints.

Since Green Book solutions may occasionally seem

incompatible with traditional park road values, it is

important to underscore that AASHTO standards are

intended to serve as general recommendations rather

than as inflexible stipulations. Unless a historic road is

part of the federal highway system, it is permissible for

the CLR to propose alternative solutions that are more

historically appropriate and context-sensitive. The

Green Book acknowledges that recreational roads have
HISTORIC ROADS 35

the process can be time-consuming and challenging on

technical, aesthetic, and bureaucratic levels, it can lead to

creative solutions that harmonize the complex goals of

resource protection, safety, and sustainability.

Compliance

Park road treatment proposals must also take into

account the various compliance procedures that

regulate development practices on federal lands. The

National Environmental Policy Act (NEPA) and Section

106 of the Historic Preservation Act (Section 106)

should be considered from the outset of the CLR

process to avoid unnecessary problems when it comes

time to implement treatment recommendations.

Although the CLR does not legally require public input,

the potential for treatment recommendations to affect

visitors, neighbors, and natural resources suggests that

the CLR scope of work consider the possibility of

complying with the NEPA public input process. When

an environmental assessment (EA), environmental

impact statement (EIS), or Section 106 compliance

process is required to implement the proposed

treatment recommendations, all affected parties should

be included in the CLR development process to

facilitate subsequent administrative procedures.

In addition to these general compliance procedures,

park road projects are potentially subject to review

under Section 4(f) of the Department of Transportation

Act of 1966, which declares it public policy to “preserve the natural beauty of the countryside and public

park and recreation lands” and prohibits federal approval

of transportation projects that use public parks, historic

sites, recreation areas, or wildlife refuges unless there is

“no feasible and prudent alternative” and the proposal

“includes all possible planning to minimize harm” to the

site. For 4(f) purposes, “use” is defined broadly enough

to include noise and other indirect environmental

impacts. Since 4(f) focuses specifically on a road’s use of

parkland, treatment recommendations that call for lanewidening, altered alignments, or the development of

additional features may trigger 4(f) review. The CLR

team should consult with the park FHLP coordinator

throughout the report’s process to ensure compliance.

While Section 4(f) has the potential to be a strong ally in

historic road preservation efforts, varying interpretations

unique requirements and endorses the use of sitespecific design criteria “intended to protect, and

enhance existing aesthetic, ecological, environmental,

and cultural amenities.” AASHTO standards for

recreational roads with design speeds under 60 kph (37

mph) permit more horizontal curvature, narrower

shoulders and recovery zones, and a greater diversity of

safety barriers than called for in utilitarian highway

development (AASHTO 2001; 443-53; quoted, p.

443).

The FHWA has similarly recognized the value of contextsensitive design and provided guidance for taking advantage of the inherent flexibility of AASHTO standards in its

1997 publication, Flexibility in Highway Design. Additional assistance in understanding AASHTO standards and

coordinating them with historic preservation concerns

can be found in Paul Daniel Marriott’s Saving Historic

Roads: Design & Policy Guidelines (Marriott 1998).

Since road standards are geared to projected use

patterns, the manner in which a park road is officially

classified plays an important role in defining standards and

determining appropriate solutions. Both the NPS and

AASHTO recommend different treatments depending

on the functional classification and expected traffic burdens

of a roadway. As outlined in the 1984 Park Road

Standards, the major categories of NPS park roads are

Principal Park Road/Rural Parkway, Connector Park

Road, Special Purpose Park Road, and Primitive Park

Road. Administrative roads have two subcategories and

Urban Parkways and City Streets are also accorded

separate guidelines. Where conditions warrant, it may

be possible to reclassify a historic road to facilitate

compliance.

In some cases, it may be desirable to propose solutions

that exceed standard interpretations of flexibility. For legal

and administrative reasons, it is necessary to document

alternative treatments through what is known as the

“design exception process.” Demonstrating reduced

travel speeds, light traffic volumes, and lower-thannormal accident rates can help make the case for

context-sensitive design exceptions aimed at preserving

the character-defining features of historic roads. All

recommendations to explore the design exception

option should be made in close consultation with park

staff, PRP personnel, and regional FHWA officials. While
36 L A N D S C A P E L I N E S

of the legislation’s key phrases can limit its effectiveness.

Treatment recommendations should conform to the

act’s intentions. Section 4(f)’s planning requirement also

makes it a potential source of funding for CLR development.

Given the extent of many park road systems, it may be

advantageous to develop programmatic agreements to

resolve compliance issues rather than deal with separate

but similar sites on an individual basis. Standard roadway cross-sections, pavement widths, guard wall

patterns, and vegetation management procedures can

be generated to guide treatment activities along an

entire roadway or sub component. Compliance

agreements for individual sites with unique requirements should be developed independently.

Since road projects have limited funding for compliancerelated activities, it is essential to work with the PRP and

other potential partners to understand what projects are

being scheduled, which have the potential to effect

historic park roads, and when compliance mandates

might help fund CLR development. PRP managers are

beginning to recognize the merits of undertaking cultural

landscape research to assist their park road projects and

are coordinating with the regional cultural landscape

programs to accomplish this effort.

DEVELOPING A MANAGEMENT

PHILOSOPHY

The treatment section of the CLR should provide a

management philosophy statement that defines the

principle objectives of the historic road stewardship plan

and outlines the general nature of the treatment activities

required to achieve these objectives. This management

philosophy statement should articulate both long-term

stewardship strategies and specific treatment goals. It

should clearly express the road’s historic significance and

outline the preferred approach to preserving the

landscape’s essential physical characteristics. The management philosophy should be consistent with general park

resource management concerns, with FHWA requirements, and with the Secretary of the Interior’s standards

for the treatment of cultural landscapes.

The Secretary of the Interior’s Standards for the Treatment

of Historic Properties with Guidelines for the Treatment of

Cultural Landscapes defines four general approaches to

landscape stewardship: Preservation, Rehabilitation,

Restoration, and Reconstruction. While one of these

approaches will generally be defined as the principle

treatment philosophy for the overall resource, individual

segments and component features may require various

treatments depending on existing conditions and

management goals. It is important to remember that

the highway engineering community employs similar

terminology to describe different and in some cases

contradictory processes. Communications with

engineering staff should clearly establish which definitions of these terms are being applied and what the

results of the proposed actions will entail.

Preservation Preservation retains the existing character and fabric

of the historic park road landscape with the highest

possible degree of integrity in regard to materials,

setting, design, feeling, and location. Preservation-based

treatment plans typically emphasize maintenance and

stabilization regimes aimed at ensuring the longevity of

existing features. Measures may be taken to protect

and stabilize historic road resources, and limited and

sensitive upgrading of technical systems is permissible,

but distinctive materials, features, and design elements

should not be substantially altered or replaced. When

original features or materials have deteriorated to the

point that they compromise the historic character or

safety of the site, limited replacement-in-kind is permitted. Discreet stabilization measures designed to

reinforce or extend the longevity of historic features can

also play a part in preservation plans. These minor

interventions should not impact the overall character

and integrity of the historic park road landscape.

The ever-changing demands placed on park roads make

strict preservation a difficult goal to achieve. Modern

traffic burdens and safety requirements – along with

general age-related deterioration of heavily used

functional features – frequently mandate technical

upgrades and material replacements that, even when

kept within context-sensitive limits, exceed standard

definitions of preservation. If a historic park road’s

design has been deemed extraordinarily significant

(through NHL designation, for instance), or current use
HISTORIC ROADS 37

can be maintained at or returned to levels commensurate with historic patterns, then preservation is a more

viable option. Some historic roads or road segments

have been preserved by restricting travel to one

direction, regulating vehicle size, or reserving them for

non-motorized travel.

Rehabilitation aims Rehabilitation to protect the essential character

of the park road landscape while accommodating

compatible uses that may require modest alterations to

the resource’s physical fabric and design qualities.

Rehabilitation allows for the replacement of deteriorated features on a wider scale than preservation-based

treatments, along with more extensive substitution of

compatible materials designed to meet current needs.

Because rehabilitation-based treatment plans respond to

current demands while safeguarding key historic values,

they often provide the most acceptable means of

resolving the inherent tensions of park road stewardship. The primary challenge in devising rehabilitation

strategies is to identify character-defining features and

ensure that planned alterations do not compromise the

road’s overall historic character.

Rehabilitation allows for minor lane-widening and

alignment improvements, updating paving materials and

technical systems, and the addition of compatible safety

measures. It provides more flexibility for replacing

hard-to-find plant species and construction materials,

such as locally gathered stone, which is often no longer

available due to changing environmental regulations.

Modifications must be carefully considered and meticulously specified to ensure that they do not detract from

the road’s overall character and that remaining historic

materials, features, and spatial relationships are protected.

Restoration Restoration focuses on returning a historic road to its

appearance during the period of significance. This

process may include the reconstruction of damaged or

missing features and the removal of elements from

other eras that detract from the historic scene. Limited

upgrading of technical systems is permitted as long as

these interventions are discreet and compatible.

Existing features from the period of significance will be

retained and stabilized. All changes should be carefully

researched and specified to ensure that they are

historically accurate in regard to design, materials, and

overall impression. A long-term management plan

should be devised to maintain the desired historical

appearance.

Given the evolving demands on park roads, comprehensive restoration to historic periods is usually impractical, unless future use can be limited to compatible

functions. Restoration may be a viable strategy for

bypassed road segments or for roads where current use

does not threaten the integrity of the resource. For

historic road segments that function apart from the

main visitor circulation system – such as the vernacular

lanes of military parks or abandoned sections of the Old

Natchez Trace – restoration may be a desirable and

practical strategy. More limited restorations can play an

important role in park road stewardship: vegetation can

be restored to historic patterns, designed views can be

restored through selective trimming, damaged or

missing walls, signs and smaller features can be repaired

or replaced in historically accurate patterns, and

incompatible elements can be removed to reproduce

historic appearances.

Reconstruction is Reconstruction the process of recreating a nonsurviving site, structure, feature, or landscape. This

approach should only be employed when the nonsurviving resource is deemed exceptionally significant

and sufficient documentary evidence exists to ensure an

accurate replication of the historical antecedent.

Because of the inherent technical challenges and

philosophical implications, reconstructions require

extensive consideration and high-level review, culminating with written approval from the NPS Director. If

reconstruction is deemed a suitable strategy, the artificial

nature of the landscape should be explicitly identified

and interpreted.

While large-scale reconstruction will rarely be an

appropriate strategy for historic park road management,

it may occasionally be desirable to reconstruct short

segments that have been lost through natural processes

or administrative actions. A landslide may destroy a

section of historic road, for instance, or an earlier

alignment may be brought back into use for various

reasons. The reconstruction of small-scale features can

contribute to comprehensive stewardship plans guided
38 L A N D S C A P E L I N E S

by other treatment philosophies. Even minor reconstructions should be carefully documented and conform

to the Secretary of the Interior’s standards.

Given the size and complexity of most historic park

roads, it is likely that park road treatment plans will

incorporate various treatment philosophies to address

the range of conditions encountered along the roadway

corridor. It is generally desirable to choose a primary

stewardship philosophy based on the character and

significance of the resource as whole and then articulate

the nature and extent of site-specific treatments. The

cumulative results of individual treatment recommendations should clearly reflect the guiding principles of the

overall plan.

Developing the Treatment Plan

Once the overall treatment approach has been defined,

a detailed historic road treatment plan should be

developed. The treatment plan should outline the

overall philosophy, provide general guidelines for

treating common resource management issues, and

include detailed specifications for the treatment of sites,

features, and broader landscape or planning elements

that have been identified as requiring restoration,

preservation, rehabilitation, or reconstruction. Maintenance regimes should be outlined, both for resources

currently deemed in satisfactory condition and to ensure

the success and longevity of proposed enhancements.

The treatment plan can also propose interpretative

measures designed to enhance visitor awareness of the

road’s general history and significance or call attention to

specific features or preservation measures.

The treatment plan should clearly articulate proposed

alterations, material specifications, construction techniques, and maintenance directives, being sure to

employ terminology and graphic conventions familiar to

highway engineers, road construction contractors, and

maintenance personnel. The “Anatomy of a Road”

section should be consulted for clarification when

necessary. Standard sections, plans, and profiles should

be prepared according to the scope of the proposed

interventions. Reproductions of historic plans, design

details, and construction photographs can be useful for

demonstrating design proposals and workmanship

SIDEBAR 5: HISTORIC PARK ROAD

TREATMENT GUIDELINES

• Preserve as much of the historic road corridor as possible,

including constructed features and associated landscape

settings 

• Consider managerial solutions before proposing physical

alterations to historic road landscapes 

• Promote alternative transportation to reduce traffic volume

and control circulation patterns

• Maintain historic road alignments, cross-sections and profiles

as closely as possible

• Realign roads only when absolutely necessary and try to

retain historic character, views, width, and curvature

• Retain original road width where possible; consider

alternative techniques such as stabilized shoulders

• Preserve, rehabilitate, or find compatible replacements for

original paving materials

• Preserve, restore, or replace-in-kind historic features such

as barrier walls, fences, and guardrails, curbs, gutters,

culverts, signage, scenic pullouts, bridges, and tunnels

• Limit the construction of new barriers or systematic

rehabilitation to areas with demonstrated safety hazards

• Use materials and construction methods that replicate the

effect of historic building practices

• Modern materials and construction methods that reduce

costs and enhance durability should only be used where they

do not detract from historical character

• Choose materials and methods that are sustainable,

compatible, and cost-effective in the long term

• Maintain and restore historic vegetation patterns, especially

in regard to corridor-width, canopies, and planned vistas

• Protect associated scenic, natural, and cultural features that

are part of the character of the road system including rock

formations, vegetation, water bodies, views, agricultural

areas, buildings, structures, markers, and monuments

• Preserve ethnographic resources and protect archeological

sites

• Develop interpretation programs to enhance public

awareness of park road history and build support for

historic road preservation

techniques. Additional information on the general form

and content of the treatment plan, including cost

estimates and project agreement forms, can be found in

A Guide to Cultural Landscape Reports and the accompanying Landscape Lines.
HISTORIC ROADS 39

While the CLR team or individual preparer will bear

primary responsibility, the treatment plan should be

developed in cooperation with park staff, PRP personnel, and the FHWA’s regional FLHP coordinator. The

State Historic Preservation Office should also be

consulted when dealing with roads listed on or eligible

for listing on the National Register. NPS regional staff

can also provide guidance on various technical, programmatic, and philosophical matters. Valuable

information can often be obtained from staff in parks

that have extensive experience in historic park road

management, such as Glacier, Acadia, Yellowstone, and

Yosemite. Collaborating with all the relevant professional staff, partners, and regulatory officials throughout

the CLR development process will greatly facilitate

approval and implementation phases.

HISTORIC PARK ROAD TREATMENT

CONSIDERATIONS

This section provides an overview of some of the most

common treatment concerns associated with historic

park road management. While a range of topics and

potential solutions are discussed, this brief survey is

neither comprehensive nor definitive. Every historic

road presents unique challenges requiring individualized,

site-specific solutions, while treatment techniques and

stewardship philosophies are constantly evolving in

response to new demands, new technologies, and

ever-changing social, administrative, and financial

concerns. While every historic park road project entails

unique solutions, the following survey covers many of

the ways in which the NPS and FHWA have collaborated to preserve and maintain America’s national park

roads and parkways.

Location and Alignment

Park road designers took enormous care to locate

roads in relationship to natural and cultural features and

produce alignments that combined beauty and utility

through subtle adaptations to local conditions, scenic

features, and administrative concerns. Any changes to

these basic attributes should be carefully considered.

While site-specific remediation may be merited to

accommodate new programmatic demands, adapt to

changing natural conditions, or alleviate demonstrated

safety hazards, the systematic alteration of historic

curvature to conform to contemporary design standards

can significantly compromise a park road’s experiential

qualities and historic integrity. Original design intent can

be illustrated with historic design documents and

invoked to justify variations from current codes. Low

accident history records can be employed to demonstrate the functional safety of roads that do not meet

contemporary standards for minimum curvature.

Regulatory measures such as lower speed limits,

restrictions on vehicle length, and one-way circulation

patterns can reduce potential hazards with minimal

physical impact on historic resources.

These techniques were employed on Mount Rainier’s

Eastside Highway, where a proposed realignment

would have significantly altered a historic bridge and its

designed approaches. The significance of the original

design was demonstrated and speed regulations and

improved enforcement were combined with a modest

increase in curve radius to produce a solution that

reconciled contemporary safety concerns with park

road preservation. In Sequoia National Park, tour bus

companies agreed to stop using a particularly circuitous

portion of the Generals Highway, making it possible to

retain a series of tight curves that contribute significantly

to the road’s historic character and significance. In

Yellowstone National Park, however, historic tour road

Figure 20. Classic park road with tight curvature calculated to

provide thrilling views of natural scenery; changing historic

alignment to conform to modern standards not recommended;

Glacier Point Road, Yosemite National Park. (Davis 2000)
alignments were systematically modernized to accommodate contemporary traffic. While both horizontal

and vertical curves were lengthened and regularized,

spiral transitions were employed to evoke the historically winding alignment.

Profile

Since most existing park roads were designed with

relatively gentle and consistent grades to accommodate

mid-twentieth century automobiles, there is generally

less pressure to alter their vertical alignment. The most

common reasons for altering historic profiles are to

reduce excessive vertical curvature that restricts sight

distance or to smooth out “roller-coaster” dips and

bumps. Minor regrading to eliminate dangerous

blindspots can often be accomplished without dramatically altering overall road quality, but achieving complete

conformance with contemporary standards in the

mountainous terrain of many parks may require

excessive excavation and/or dramatic relocations.

While smoothing out minor irregularities may afford a

more consistent and comfortable ride, excessive

standardization can eliminate the sense of serendipity

and dynamic interaction with the landscape that

differentiates park road travel from ordinary motoring.

Historic bridges can produce profile irregularities that

restrict sight distance or create sudden and potentially

dangerous bumps, the effects of which are often

rendered more hazardous by accompanying lane-width

constrictions. During the rehabilitation of the White

Bridge at Vanderbilt Mansion National Historical Site,

the vertical alignment was raised and flattened to

eliminate an abrupt roller-coaster profile that caused

excessive wear and tear on vehicles, their occupants,

and the bridge itself.

Pavement

Pavement rehabilitation is one of the most common

and challenging aspects of historic park road management. Pavements wear out. Subgrades deteriorate.

Vehicles get longer, wider, and heavier and many

motorists want to drive faster and more effortlessly.

Engineering standards evolve to accommodate these

new demands, calling for wider travel lanes and broader

shoulders. These alterations are often implemented

during resurfacing projects, since FLHP funding for

functional rehabilitation is generally accompanied by

requests to adhere to prevailing standards.

Adding lanes, widening existing lanes, and expanding or

adding shoulders may enhance travel flow, but at

considerable cost to the historic integrity and experiential character of traditional park roads. Even seemingly

minor lane-widening and shoulder adjustments can

adversely affect historic character by increasing the

pavement’s domination of the forward view, creating

greater separation between motorists and their

surroundings and producing an incentive toward higher

speeds, which further compromises the park road

experience and may cause additional safety hazards.

Cultural resource specialists should work closely with

park management, PRP staff, and FLHP engineers to

underscore the importance of historic pavement

configurations and ensure that pavement-widening is

kept to the minimum consistent with visitor safety.

Alternatives such as signage, speed reductions, and

vehicle restrictions should be thoroughly explored.

Minor widenings at curves and other hazard points,

along with the introduction of occasional pullouts for

slow-moving traffic, can alleviate many problems.

Where systematic lane-widening is ruled unavoidable,

the impact on the resource should be duly noted, even

if this means acknowledging the loss of historic integrity.

The expansion or addition of paved shoulders can be a

means of effectively widening the travel surface. This

approach should be carefully reviewed, however, since

the visual and perceptual results are similar to straightforward pavement widening. A less visually obtrusive

means of enhancing safety and overall performance is to

provide stabilized earth, gravel, or turf shoulders.

Stabilized shoulders allow vehicles to recover from

minor deviations or pull safely off the main travelway,

yet they are less noticeable and more permeable than

paved shoulders, reducing excessive water runoff

concerns.

Modern motor traffic places tremendous demands on

historic pavements, many of which were built with

minimal sub grades and primitive surface materials.

40 L A N D S C A P E L I N E S
While historic dirt, gravel, macadam, brick, and

cobblestone surfaces should be preserved whenever

possible, mid-twentieth-century concrete or bituminous aggregate pavements can often be replaced with

improved modern materials without compromising the

road’s overall integrity. Major repaving projects often

afford the opportunity to improve subgrades and

drainage systems, further enhancing the performance

and longevity of historic park roads. When historic

surfaces have a distinctive tint, texture, or composition,

these qualities should be reproduced with compatible

modern materials. The red-tinged pavements that

harmonize many Southwestern park roads with their

surroundings have been retained through multiple

resurfacings. When sections of Colonial Parkway

Figure 21. Comparative views showing effects of changes to alignment, road width, and clear zone: (A) Classic narrow winding park road

laid lightly on the land with tight curvature, relatively steep grade, and no shoulders, (Hawaii Volcanoes National Park); B) Longer curves,

gentler grade, and slightly wider pavement, with minimal gravel shoulder and vegetation approaching the edge of travelway, (Yosemite

National Park); C) Recently rehabilitated road with longer curves, wider paved shoulders and expanded clear zone, (Yellowstone National

Park); D) Four-lane dual roadway with median in high traffic area. (Yellowstone National Park) (Davis 1996-2001)

required rehabilitation, considerable effort was made to

emulate the original rough-textured concrete pavement, which was itself a 1930s attempt to evoke

historic shell road surfaces in modern materials. A

recent resurfacing project at Acadia National Park

employed a coarse final “chip coat” layer to restore a

rustic crushed-stone appearance that had been compromised by multiple overlays with conventional bituminous concrete.

A common paving practice that should be avoided is the

repeated layering of new material over existing surfaces.

The accumulation of multiple pavement courses over

time alters the relationship between the travel surface

and its surroundings, effectively lowering the height of

(A) (B)

(C) (D)

HISTORIC ROADS 41
42 L A N D S C A P E L I N E S

safety barriers or creating potentially dangerous dropoffs

that are rendered more hazardous by the narrow lanewidths and minimal shoulders of historic park roads.

Drainage

Properly functioning drainage systems prevent water

from accumulating on park road pavements or undermining the basic road structure. Most paved park roads

employ a slight crown to shed water. On curves, a

banked or “superelevated” pavement may direct water

to the inward or downhill side. Pavement rehabilitation

programs should retain historic configurations unless

they have proven ineffective, in which case minor

improvements can generally be made without compromising the road’s historic character.

A variety of techniques were used to accommodate

surface runoff and channel other water sources such as

intersecting streams, springs, and waterfalls. Shallow

swales or ditches positioned at the edge of the road

shoulder were often sufficient in areas with modest

rainfall, permeable soils, and moderate terrain. Where

conditions were more extreme or a more finished look

was desired, gutters lined with local rock or stone

pavers afforded durable and attractive options. Stabilizing gutters in this manner was a labor-intensive process,

so this technique is more likely to be found in commemorative military parks and on roads where the

CCC was involved in construction or rehabilitation

efforts.

Historic ditches, swales, and gutters require ongoing

maintenance to remove obstructions and preserve their

appearance and structural integrity. Many ditches and

gutters become seriously clogged over time, requiring

more extensive remedial efforts. Much gutter damage

is due to natural processes, but historically significant

stone gutters have also been compromised by overpavement with bituminous concrete. While such

modern surfaces may be less expensive to apply and

easier to maintain than historic materials, this treatment

is not desirable and should be reversed wherever

possible. Care should be taken to restore the original

configuration and preserve historic paving materials as

much as possible. Replacement-in-kind is the preferred

treatment for lost or damaged materials.

Culverts are another means of controlling surface runoff

and containing water sources that intersect the roadway. When culverts are used to divert surface runoff,

they are often employed in association with drop inlets

or curb inlets that collect water from the road surface.

In some cases culverts may extend a significant distance

from the roadbed to ensure that exiting water does not

cause damaging erosion. Dimensions range from less

than a foot in diameter for smaller culverts and

underdrains to ten or twelve feet in span or diameter.

Wider spans are generally referred to as bridges, though

definitions vary considerably. In many cases the terms

are used interchangeably. Historic construction

materials include wood, stone, cast iron, vitrified clay,

galvanized steel, and concrete. Headwalls, which help

Figure 22. Attentive maintenance is necessary to ensure that

historic drainage features such as these stone-lined gutters in

Acadia National Park do not become obstructed by vegetation,

siltation or other natural processes. (Foulds 1993)
HISTORIC ROADS 43

channel water, secure the culvert, and stabilize the

surrounding fill, were frequently constructed of native

stone masonry or stone-faced concrete, especially

when visible from the roadway or associated circulation

networks.

Historic culverts may require a variety of treatments.

They can clog with debris, collapse from excessive

loads or material failure, and be undermined, dislocated

or washed away by chronic or catastrophic flooding.

Inlet grates, linings, and headwalls deteriorate, especially

in the harsh environments of many national park roads.

Road widening and realignment can also necessitate

culvert replacement, extension, and relocation.

When culverts require treatment due to structural

failures or roadbed alterations, there is usually no

objection to replacing subterranean sections with

modern materials or more efficient configurations.

Exceptions may occur in the case of historic wood or

masonry culverts whose materials and craftsmanship

contribute measurably to the road’s character and

significance. When the actual materials and craftsmanship are deemed significant, as may be the case with

hand-constructed culverts on some carriage drives or

military park roads, or when the barrel of the culvert is

visible to park users, then treatments should employ

compatible materials and construction methods.

Most culvert treatment recommendations will concern

headwalls, since these are usually the most visible and

highly crafted elements. The preferred alternative is to

preserve historic headwalls in place, stabilizing them and

replacing lost or damaged materials in-kind using similar

workmanship. On road-widening projects, it may be

possible to relocate historic headwalls by moving them

as integral units or by dismantling them for reassembly

in conjunction with new or lengthened culverts.

If original headwalls are too deteriorated, or additional

culverts are required for various reasons, existing headwalls,

historic photos, or original plans can be consulted as the

basis for reproductions, which should follow historical

precedents as closely as possible. Since current laws

generally prohibit quarrying within parks, imported

materials should be matched as closely to historic stonework to avoid visual discrepancies. To save time and

reduce on-site skill requirements, entire headwall assemblies can be precut and delivered to the site.

“Simulated stone,” or reinforced concrete poured in

forms designed to emulate traditional masonry, can be

an economical alternative to hand-laid stone headwalls.

The concrete surface should be tinted to harmonize

with historic rockwork, either in the original mix or

with surface color applications, which may be varied for

greater naturalness. Though less desirable than authentic stonework, simulated stone is generally preferable to

unadorned concrete. Some parks may consider it an

acceptable solution, especially for less visible headwalls

or locations where motorists will be passing at moderate speeds.

Figure 23. Many historic gutters have been overlain with

bituminous concrete to ease maintenance and repair; such

inappropriate treatments should be reversed whenever possible.

(Foulds 1993)
44 L A N D S C A P E L I N E S

Neither simulated stone nor neo-rustic hand-crafted

stonework is appropriate for headwalls or other

features on park roads that historically displayed

alternative masonry techniques. Colonial Parkway

designers employed a Flemish-bond brick veneer to

evoke historic masonry traditions, for instance, and

some later parkways and park roads adopted a

“streamlined” aesthetic of unadorned concrete, which

should be retained for reasons of visual consistency

and historic authenticity. Historic design motifs,

colors, textures, dimensions, and construction

techniques should be emulated as closely as possible

when treating these headwalls.

Retaining Walls

Many historic park roads contain retaining walls and

other structures designed to support the roadbed and

stabilize slopes above or below the roadway. Generally constructed of locally quarried stone masonry,

historic retaining walls vary from minor grade

correctives a few feet in length and inches in height to

immense structures towering hundreds of feet above

steep cliffs and roaring rivers. Most range somewhere

in between and, like headwalls and other examples of

NPS rockwork, were designed to harmonize with their

surroundings. In some cases, such as Glacier National

Park’s Going-to-the-Sun Road, retaining walls are

spectacular structures that contribute substantially to the

road’s visual character and historic significance. In other

cases, they are all but invisible to motorists, lying below

the travelway or disappearing behind subsequent plant

growth and soil accumulation.

Retaining wall treatments may range from minor

repairs to significant structural rehabilitation to wholesale replacement when catastrophic failure occurs or

road-widening or realignment requires changes in

length, height, or location. Minor repairs should be

aimed at preserving and stabilizing the original historic

fabric. Permanently lost or damaged materials should

be replaced in-kind whenever possible. Major stabilization efforts will generally require extensive collaboration

with engineers and geotechnicians, especially when the

original structure has exhibited signs of mechanical

failure or the surrounding terrain has slumped or

shifted. If significant alterations are required, rehabilitation measures should not detract from the appearance

of walls and slopes that are visible to the public.

When natural forces, road-widening, or realignment

projects necessitate the reconstruction, relocation, or

extension of historic stone retaining walls, efforts should

be made to salvage and reuse historic materials and

emulate original design patterns and masonry techniques. Since the additional cutting and filling that often

accompanies road-widening and realignments generally

increases the need for retaining walls, salvaged materials

will rarely be sufficient. Historical research can sometimes identify the location of original quarries, which can

serve as sources of compatible material if quarrying

within the park is allowed. Some parks have been able

Figure 24. Historic stone culvert headwall salvaged and

numbered for reassembly after road-widening is completed,

Yellowstone National Park. (Davis 1996)

Figure 25. Modern pre-cut stone headwall awaiting installation

on road rehabilitation project, Yellowstone National Park. (Davis

1996)
HISTORIC ROADS 45

to develop modest reserves of compatible material by

collecting suitable stones from landsides and other

naturally occurring rockfall. When rock must be

imported from quarries outside the park, it should

match the color, texture, and shapes of historic materials as closely as possible.

While traditional stone masonry techniques are

preferable, stability factors and budgetary concerns may

persuade parks to pursue other options. Reinforced

concrete retaining walls faced with hand-laid stone

veneer are generally more compatible with the historic

character of park roads than simulated-stone fabrications, though the latter may be more economical in

some situations. In either case, the scale, color,

texture, and patterning should be based on local historic

precedents, not on generic prototypes. For simulated

stone, it is sometimes possible to ensure greater

veracity by casting forms from historic rockwork. Joints

between concrete sections will be less visible if they

follow the “rock” contours and are tinted to match the

“mortar” of the poured concrete. Tints can be applied

to the simulated stonework, as well. When employed

with skill and subtlety this technique can appear quite

realistic to casual observers. As with culvert headwalls,

the inauthenticity of simulated stone retaining walls will

be less apparent if they are only used in areas where

visitors are restricted to their cars and driving at moderate speeds.

Safety Barriers

Safety barriers such as guardwalls, guardrails, guiderails,

and guideposts are common components of many

historic park roads. Whether comprised of rugged

boulders, hand-laid stone masonry, rough-hewn

timbers, or hand-split rails, rustic safety barriers have

long been character-defining features of national park

road landscapes. While many of these barriers were

intended to deflect vehicles traveling at relatively low

speeds, their function has always been as much perceptual as physical. In addition to delineating the edge of

the roadway, their rugged appearance provides psychological reassurance, while their rustic associations recall

America’s pioneer roots. Given their widespread

presence, visual appeal, and compelling historical

associations, rustic safety barriers can be considered

character-defining features not just of individual park

roads, but of the National Park System in general

While the historical significance and character-defining

nature of traditional safety barriers is incontestable, developing appropriate treatment plans is one of the most challenging aspects of park road management. Not only is there

considerable pressure to accommodate evolving engineering standards, but many historic walls and rails are showing

their age. The normal deterioration of wood and masonry structures is often exacerbated by the harsh climates

to which many park road barriers are subjected. Rockfall,

avalanches, landslides, and vehicle impacts can cause

problems ranging from minor damage to major failure.

The need to develop preservation-oriented alternatives to

Figure 26. Formwork and foundation for simulated stone

retaining wall, Yellowstone National Park. (Davis 1996)

Figure 27. Simulated stone retaining wall with integral culvert

and crenellations: this treatment is best restricted to areas where

visitors do not come close enough to discern the artificial nature

of the materials, Yellowstone National Park. (Davis 1996)
46 L A N D S C A P E L I N E S

potentially incompatible rehabilitation or replacement

programs is most pressing when severe physical deterioration is coupled with changing user demands and/or

heightened managerial concerns for conforming with

conventional engineering standards.

The CLR can be a persuasive vehicle for promoting

treatments aimed at retaining or restoring historic

guardwalls or guardrails, or, when absolutely necessary

rehabilitating them in ways that retain the experiential

character and historic integrity of park road landscapes.

While visitor safety is clearly paramount, it is not always

necessary to comprehensively upgrade historic barriers to

conform with standards calculated for non-park roads.

Preservation, minor rehabilitation, or replacement in-kind

will be sufficient treatment alternatives in many cases. This

is particularly true when low or non-existent accident

history rates indicate that historic barrier systems have safely

accommodated local demands. Not only do historic park

roads generally experience lower speeds and traffic

volumes than comparable non-park arteries, but park

motorists typically adjust their driving behavior to accommodate the tight turns, narrow lanes, and steep side slopes

that frequently characterize the park road experience.

From a standard highway engineering perspective, these

characteristics would normally mandate extensive retrofitting with new or improved safety barriers, but the inherent

“traffic calming” nature of the park road experience has

been demonstrated over decades of remarkably safe use.

While general AASHTO standards are often cited to

support extensive guardwall rehabilitation and new

construction on historic park roads, the official NPS Park

Road Standards bulletin calls for a more conservative and

context-sensitive approach. Observing that “Guardrail or

guardwalls should be installed at points of unusual danger

such as sharp curves or steep embankments, particularly at

those points that are unusual compared to the overall

characteristics of the road,” the 1984 Park Road Standards

advises that “The criteria used for warranting guardwall

installation on high-speed, high-volume highways do not

apply to low-speed, low-volume conditions found on

most park roads” (NPS 1984, p. 32).

Interpretations of what constitutes unusual danger and

acceptable criteria vary considerably from park to park

and from profession to profession, which is why safety

barrier treatment recommendations should be developed in consultation with park staff, PRP representatives, and FHWA engineers to ensure that all parties

agree on a preferred course of action. The targeted

construction of improved safety barriers in demonstrated problems areas may be necessary, in which case

every effort should be made to harmonize with historic

prototypes. Less physically obtrusive alternatives such as

lowered speed limits, vehicle-size restrictions, and oneway traffic patterns should also be explored. The final

decision on all such matters is the responsibility of the

individual park superintendent.

Figure 28. Historic stone safety barriers have functioned

successfully in the low-speed, low-volume context of most park

roads; Cadillac Mountain Road, Acadia National Park. (HAER

1995)

Figure 29. Motorists generally adapt their driving to park road

conditions, making extensive guardwall construction

unnecessary in locations with documented low accident rates

such as this Lassen Volcanic National Park highway. (Davis

2001)
HISTORIC ROADS 47

The NPS and FHWA have worked cooperatively to

develop a variety of safety barriers that meet contemporary standards while emulating historic design

precedents to varying degrees. These treatments have

been employed where existing barriers were considered unsafe or where additional safeguards were

deemed necessary. In many cases, mutual decisions

have been made to preserve, restore or replace historic

guardwalls without major alterations so that the historic

character and significance of roadway remains

uncompromised. The degree to which guardwall

additions and alterations will affect the overall historic

integrity of a park road will depend on the nature of the

revisions and the extent to which safety barriers serve as

character-defining features.

Masonry Walls

Masonry guardwalls are among the most common and

characteristic features of the national park road system.

Some reflect the efforts of the Army Corps of Engineers

and other pre-NPS proprietors, but most date from the

“Golden Age” of park road-building between the two

world wars, embodying the principles of rustic design

propounded in contemporary plan books and discussed

at length in various publications on NPS design history.

Within the general rustic framework, there is considerable variety in size and shape, including flat-topped walls,

various crenellated compositions, and large, independently-placed boulders. Rock size, conformation, and

joinery vary considerably, generally reflecting local building

patterns and native materials. Both dry-laid and mortared

masonry were common. In some cases, unadorned

concrete was used to harmonize with the surrounding

terrain, evoke Southwestern adobe building styles, or

produce an intentionally modern appearance.

Masonry guardwalls suffer various forms of physical

failure. Individual stones and small segments can be

damaged or dislocated by rockfall, vandalism, vehicle

impact, and general weathering processes. Entire

sections can be lost to landslides, avalanches, flooding,

and major crashes. Road relocations, pavementwidening projects, and increased safety concerns can also

create a need for wall rehabilitation, construction, or

reconstruction.

For guardwalls that are in generally good condition,

preservation accompanied by stabilization and routine

maintenance is almost always the preferred policy.

Where minor to moderate repairs are necessary, limited

restoration with compatible materials and workmanship

is generally the most desirable treatment. Suitable rock

should be acquired through salvage or local quarrying

from historic sources, or, if necessary, by matching

sources beyond park boundaries. Dry-laid stone should

not be repaired with mortared masonry techniques and

concrete should never be substituted for mortar. Stone

size, orientation, and coloring should match as closely as

possible. Ideally, the weathered surfaces of stones should

face outward to help harmonize repair work with historic

fabric. Various weathering agents can be applied to speed

the process if necessary. Tool marks from quarrying or

cutting operations should not be visible.

Where the extent of the damage is more severe, or

where major rehabilitation or new construction projects

are being implemented, developing appropriate treatment strategies can be more challenging. Most of the

techniques and concerns associated with headwalls and

retaining walls also apply to historic guardwalls. The ideal

solution from a preservation standpoint will generally be

reconstruction or replication with in-kind materials and

techniques, but practical, economic, and regulatory

concerns may render alternative measures more

compelling. Suitable stone and masonry expertise may

not be available, costs associated with traditional materials

and hand labor may be excessive, or the desire to accord

with contemporary safety standards may mandate more

substantial protection measures. In many cases, all these

factors will come into play. Whatever the motivation,

the adoption of new materials and techniques should be

accompanied by a firm commitment to ensuring that

these measures harmonize as closely with the existing

physical fabric as possible and not impinge on the road’s

historic character and integrity.

Stone-faced reinforced concrete core guardwalls have

been used on a number of park roads and parkways as a

means of combining traditional park road aesthetics with

modern safety standards. This technique can be

effective on both accounts, but care must be taken to

ensure that masonry patterns, materials, and broader

design considerations are appropriate for the historical
48 L A N D S C A P E L I N E S

Figure 30. Masonry treatment options: A) The preferred treatment for deteriorated stone walls is to repair or replace in-kind with

compatible materials and workmanship; this wall has been spot-repaired with historically accurate dry-laid stonework, (Robert Page

1992); B) Mixing drylaid and mortared construction is not ideal, but in this Skyline Drive example, considerable care was taken to

match materials and masonry patterns, (Robert Page 1992); C) Stone-faced reinforced concrete core guardwalls can meet

contemporary safety standards while maintaining a rustic ambience, (Davis 1994); D) Newly constructed hand-laid stone guard wall

and curb at scenic overlook, Yellowstone National Park, (Davis 1996); E) Simulated stone was employed on Yosemite Park’s El Portal

massing, and location should emulate local historical

precedents. The most challenging harmonization issues

occur where concrete simulations directly abut historic

stone walls or natural rock formations. When simulated stone walls are employed on a large scale, their

uniform massing can call unwanted attention to their

artificiality. Vehicle impacts and rockfall can also shatter

the illusion of authenticity by exposing the concrete and

reinforcing steel beneath naturalistically sculpted facades.

While minor repairs to traditional rock walls are often

almost invisible, matching the form, tint, and texture of

simulated stone walls may prove more difficult,

character of the roadway. If the new walls are substantially higher, wider, or longer than their predecessors, if

their overall extent or placement is significantly altered,

if the stonework does not match, or if there is no local

precedent for masonry structures, then the mere

presence of hand-laid stone veneer does not automatically constitute context-sensitive design and significant

degradation of historic integrity and experiential character may occur.

Similar concerns apply to the use of simulated stone

guardwalls. Color, texture, “masonry” patterns,

(A)

(C)

(B)

(D)
HISTORIC ROADS 49

Road to replace extensive sections of historic stone walls lost in the 1997 flood; F) Precast simulated stone guardwalls on BaltimoreWashington Parkway were designed to provide a more formal effect, with regular coursing and a distinctive coping motif, (Lou

DeLorme 1993); G) Long sections of simulated stone guardwall can appear unnaturally uniform, especially when contrasted to historic

stone guardwalls, as in this reconstructed portion of Yosemite National Park El Portal Road, (Davis 2001); H) Rockfall and accidents

can expose the artificiality of simulated stone construction, El Portal Road, Yosemite National Park. (Davis 2001)

Timber Barriers

Rustic timber barriers are another classic component of

park road landscapes. Log guardwalls and guide rails

were erected alongside many park roads to protect

motorists and evoke cherished cultural traditions. Log

and timber rails, sunken posts, and split rail fences were

also used to control traffic on side roads and in administrative areas, to define parking areas, campgrounds, and

pedestrian paths, and, in a more conceptual sense, to

evoke America’s agrarian heritage and pioneer spirit.

especially as the original material ages. The longevity of

the tinting compounds employed to naturalize concrete

surfaces may also become a treatment issue over time.

As with retaining walls and culvert headwalls, the

artificial nature of simulated stone guardwalls will be less

apparent if they are only employed in areas where

visitors are unlikely to approach them closely. Some

parks have constructed authentic stone walls at scenic

pullouts and other parking areas while using simulated

stone in intervening areas where motorists are unlikely

to leave their cars.

(E)

(G)

(F)

(H)
50 L A N D S C A P E L I N E S

Timber barrier treatments must reconcile the desire to

maintain traditional appearances and preserve aging

handcrafted structures with need to provide appropriate

safeguards for modern motorists. The safety issue will

be of greater concern on main roadways than for

campgrounds, pullouts, and administrative areas, where

timber barriers serve mainly to contain and direct traffic.

In these cases, it will generally be more admissible to

employ a more strictly preservation-oriented approach.

Even when preservation, replacement-in-kind, or

context-sensitive rehabilitation are chosen as preferred

treatment options, it may be difficult to find compatible

materials or replicate the labor-intensive construction

processes that produced the vast majority of original

guardrails during the CCC-aided construction campaigns of the 1930s.

In many cases, deteriorated wood safety barriers have

already been replaced with steel guardrails. Modern steel

guardrails are also a common choice in situations where

realignments, road-widening, or heightened safety

concerns mandate new barrier construction. Steel

guardrail is generally not the preferred choice from a

preservation standpoint, but if this option is selected,

brown paint or a pre-weathered material such as Cortan

steel is preferable to conventional galvanized steel.

Anchoring the beams with brown-stained wooden posts

will provide a more context-sensitive approach than

100% steel construction. The State of New York has

adopted a brown-toned steel-box beam guardrail for use

on the Taconic State Parkway that more closely resembles wood construction and may be appropriate for

some NPS applications.

Steel-backed timber guardrail provides a more contextsensitive solution and has been successfully employed in

many parks to replace or augment historic log barriers.

Milled timber rails provide a reasonably approximation of

traditional NPS log construction and the steel-backing

provides sufficient strength to satisfy contemporary safety

standards for speeds up to 50 mph. For higher-speed

applications, crashworthiness can be improved by adding

a wooden spacer between the rail and post. This

“blocked-out” configuration reduces the likelihood that

vehicles will snag on a support post, producing a

smoother, safer barrier. Rounded-front steel-backed

timber guardrails have not received as extensive testing,

but they also provide a high degree of safety with even

greater historical veracity.

Major Structures

The treatment of major structures such as bridges,

viaducts, tunnels, entrance stations, and visitor centers

will generally be beyond the scope of the CLR. The

CLR should consider the impact of alterations to these

features, however, and may suggest general design

principles to help ensure that proposed changes do not

detract from the historic character and integrity of the

overall park road landscape.

The CLR should emphasize that park bridges are not

simply individual engineered structures but elements of

larger landscape compositions. Whether intended to

Figure 31. Steel-backed timber guardrails closely resemble

historical precedents while meeting contemporary safety

standards; (A) Detail showing blockout and steel reinforcement;

(B) Steel-backed rounded log rail in use, Yellowstone National

Park. (Western Federal Lands Highway Division)

(B)

(A)
HISTORIC ROADS 51

harmonize with their natural surroundings, evoke local

vernacular precedents, or contribute to the dignity of

commemorative military parks, they were designed to

fulfill practical requirements while answering deeply felt

aesthetic and symbolic needs. Preserving their original

form, function, and fabric should be the first priority.

If changing demands produce pressure to replace or

significantly alter a historic structure, managerial solutions such as vehicle-size limitations and alternative

traffic patterns should be thoroughly explored. For

exceptionally significant bridges, it may even be warranted to construct a companion structure to accommodate modern traffic, preserving the historic span as a

low-volume alternative or pedestrian route. If this

option is pursued, a key question is whether to build

the bypass in close proximity in order to showcase the

historic structure and minimize additional roadconstruction, or locate it at a sufficient distance to fully

preserve the setting and character of the original

crossing.

Major rehabilitation or replacement projects should

normally follow historical precedents as closely as

possible. Recent NPS bridge rehabilitations and

replacements have evoked historical precedents by

employing hand-laid stone facing, simulated stone

abutments, and historicist-inspired massing and details.

Care must be taken to ensure that such practices truly

reflect local precedents and that materials and workmanship harmonize with historical features and the

surrounding natural landscape.

Proposals to remove historic bridges or other roadrelated features in order to manipulate or “restore”

associated ecological systems should carefully weigh the

impact of such decisions on the historical integrity of the

road and the broader cultural values of the affected park.

Minor Structures and

Road-related Features

Minor structures such as signs, wayside exhibits, and

comfort stations contribute to the overall character and

integrity of park road landscapes. The classic routed

wood signs – and even their brown metal successors –

provide a sense of consistency and historical continuity

both within individual parks and throughout the National

Park System as a whole. Stone curbing around parking

areas and scenic lookouts, “rustic” comfort stations,

picnic shelters, water fountains, and interpretive kiosks

may seem insignificant in and of themselves, but they

help establish the tone and tenor of park road landscapes.

In some cases, minor structures may possess considerable significance in their own right. This is particularly

true of entrance signs and waysides from the classic

period of park development between the two world

wars. The 1930s Obsidian Cliff wayside interpretation

kiosk on Yellowstone National Park’s Grand Loop

Road, for instance, is independently listed in the National Register of Historic Places. Since motoristoriented wayside interpretation played a major role in

Mission 66 planning and design efforts, features from

this era should be carefully evaluated and appropriate

treatment measures devised.

When developing treatment recommendations for signs

and other minor features, it is important to recognize

that considerable variety exists within the general NPS

rustic framework. Materials, architectural styles, sign

fonts, and other design elements vary geographically,

thematically, and temporally. Variations may occur not

just from park to park, but within portions of a single

park road system developed at different times or for

Figure 32. The 1994 reconstruction of Yosemite’s Sentinel

Bridge used masonry facing and a traditional arch profile to

contextualize a modern concrete girder structure. (FHWA

1994)
52 L A N D S C A P E L I N E S

different reasons. CLR research should identify the

correct historical precedents for specific sites and

recommend appropriate treatments. Where variation

is notable within an individual site or broader park road

landscape, decisions must be made about whether to

restore the consistent appearance of a single development period or preserve existing differences to illustrate

changing historical practices.

Just as overtly modern intrusions may clash with

traditional park road aesthetics, care should be taken

not to impose inappropriately “rustic” features on park

road landscapes where these elements have no

historical precedents. Commemorative military parks

and Colonial Revival-themed historical sites are obvious

examples of this concern, but the distinctive forms of

Mission 66 signage and associated structures should be

respected as well. Even newer features, such as

elements associated with the 1976 bicentennial

celebration or other prominent cultural developments

should be evaluated and treated in view of their

potential future significance.

Roadside Landscaping

Naturalistic roadside landscaping was one of the

hallmarks of classic park road design. Great efforts

were made to harmonize park roads with their

surroundings by camouflaging signs of construction and

blending engineered features with adjacent natural and

cultural landscapes. Alignments were calculated to

minimize topographic disruptions and preserve cultural

resources. Where excavations were necessary, side

slopes were gently graded and roundly sculpted,

mimicking natural contours, promoting plant growth,

and affording greater resistance to erosion. Rock cuts

were fractured along inherent fault lines and drill marks

were minimized to produce a more natural effect.

Specimen trees were often preserved in close proximity to the roadway and treelines were generally varied

to avoid the artificial appearance of a uniform corridor.

Planting programs further enhanced the motorist’s

experience and concealed signs of construction. Native

species in naturalistic groupings were preferred, but

exotics such as Japanese honeysuckle were sometimes

employed to reduce erosion. Vegetation management

activities also included vista clearing to expose attractive

views and agricultural leases to promote traditional land

uses.

While these roadside landscape qualities may be subtler

and harder to evaluate than the engineered structures

and architectural features that often dominate historic

road analyses and treatment plans, they play equally

important roles in establishing the character and

significance of park road landscapes. The CLR should

provide comprehensive recommendations for ensuring

the preservation, rehabilitation, or, if circumstances

warrant, restoration, of historically significant roadside

landscape characteristics.

Figure 34. Yellowstone’s 1966 East Entrance Station

epitomizes Mission 66’s creative mingling of modern and rustic

styling but is no longer able to accommodate the largest

recreational vehicles, which must be routed around the

structure. (Davis 1999)

Figure 33. Sequoia National Park’s classic rustic entrance sign

was constructed by the CCC in 1935 and is listed on the

National Register of Historic Places. (Robert Page n.d.)
HISTORIC ROADS 53

Grading

Changes to historic alignments, profiles, and roadwidths will often have significant impacts on historic

roadside landscapes. Judicious planning, clear specifications, and strict contract supervision are essential to

minimize adverse effects on landforms, vegetation, and

constructed features. Relocation and rehabilitation

projects should follow the same principles that guided

historic park road development, carefully coordinating

horizontal and vertical curvature to ensure that modern

revisions “lay lightly on the land” with minimal disruption of the surrounding terrain. Where substantial grade

modifications are unavoidable, rock cuts should be

naturalized and road banks sloped and rounded in

conformance with traditional park road landscaping

practices.

Vegetation Management

Vegetation management should promote the retention

of historic plant materials, design schemes, and general

landscape characteristics by outlining routine maintenance practices, proposing long term stewardship

policies, and providing rehabilitation and restoration

plans for areas that have been disturbed by natural

disasters or construction-related activities.

Maintenance guidelines should outline the routine

procedures required to preserve and stabilize roadside

landscapes. These measures may include mowing,

pruning, watering, invasive species control, and, in

some cases, arrangements such as agricultural leases

that rely on other parties to help maintain historic

landscape qualities. Some parks have developed

comprehensive maintenance regimes tied to detailed

site plans. In some cases, such as the Blue Ridge

Parkway, these maintenance plans date back to the

original design and development period. In other cases,

roadside landscape maintenance procedures are passed

down by oral tradition and observation. Long-term

maintenance personnel can be invaluable sources of

assistance for identifying and formalizing historical

landscape management practices. Historic photographs, plans, and written descriptions can also be used

to identify desirable landscape qualities and develop

appropriate maintenance procedures.

The adoption of new maintenance practices motivated

by changing management priorities should be carefully

reviewed for their impact on traditional landscape

values. Allowing grassy areas to grow unchecked for

extended periods may be economically and ecologically

appealing, for instance, but the results may conflict with

original design intentions and distort historically significant landscape qualities.

Revegetation

Where construction activities or natural processes

produce a need for revegetation, CLR treatment

recommendations should establish appropriate goals

and procedures. While current NPS policies strongly

favor indigenous species, historical precedents may

mandate alternative approaches. Archival research and

existing condition documentation of comparable

landscapes will help determine what approaches,

species, varieties, and configurations are most appropriate. In some instances, it may be possible and desirable

to substitute more sustainable and indigenous plant

materials if similar effects can be attained.

Since revegetation projects often involve both natural

and cultural resources personnel, it is important to

avoid misunderstandings about terminology and policy

goals. For cultural resource management purposes,

“restoration” means reestablishing the type of vegetation

that existed during a specific historic period in order to

convey past design practices and cultural values. For

Figure 35. Native plant nursery for propagation of revegetation

materials, Glacier National Park. (Davis 1996)
54 L A N D S C A P E L I N E S

natural resource specialists, “restoration,” has more

ecological connotations, and aims to establish environmentally appropriate plant associations that will become

sustainable components of surrounding ecosystems.

Natural resource personnel employ the term “reclamation” for more utilitarian revegetation practices designed

to provide stable cover for disturbed areas such as

roadsides. In reclamation-oriented revegetation,

hardiness and visual appearances take precedence over

indigenous ecological values. Since similar philosophies

governed most historic roadside landscaping programs,

natural and cultural resource personnel may find

common ground with this approach.

Some parks have developed extremely sophisticated

roadside revegetation practices in which seeds are

collected from the immediate vicinity of projected

disturbances and then propagated to reestablish native

plant communities after the roadwork had been

completed. Glacier National Park has been a leader in

this movement, with strong support from the NPS

Denver Service Center.

Clear Zones

In addition to combating the loss of historic vegetation

caused by changes in pavement width and alignment, a

common concern for many historic park road managers is the pressure to expand the clear zone on either

side of the travelway. Widening the clear zone

improves sight distances and affords additional room for

motorists to avoid accidents, but increasing the distance

between the traveler and the treeline significantly alters

the historic driving experience by eliminating the sense

of intimacy and enclosure that serves as a distinguishing

characteristic of many historic park roads. Extending

sight distances and expanding recovery areas can also

encourage motorists to drive faster, further compromising historical feelings and associations and negating

gains in public safety.

Historic park road treatment recommendations should

generally seek to preserve the original relationship

between the roadway and treeline. Where treelines

Figure 37. Traditional park road landscapes with vegetation

extending close to the edge of the pavement create a unique

travel experience where motorists are intimately surrounded by

nature, Hawaii Volcanoes National Park. (Davis 1999)

Figure 38. Cutting a broad clear zone can improve safety by

providing motorists more room to recover from potential

accidents, but this approach markedly alters the motorist’s

perspective and produces greater separation between visitors

and their surroundings, rehabilitation of East Entrance Road,

Yellowstone National Park. (Davis 1996)

Figure 36. Roadside revegetation with native plants, Glacier

National Park. (Davis 1996)
HISTORIC ROADS 55

panoramas and carefully calculated views have been

obscured by impenetrable curtains of greenery. Unconstrained growth has engulfed many roadside areas

that were intentionally cleared to provide scenic variety,

contrasts of openness and enclosure, or subtle glimpses

into surrounding woodlands. In some cases, scenic

pullouts replete with interpretive signage have been

completely cut off from their intended views.

Whether caused by constraints on maintenance, lapses

in institutional knowledge about design intent, or

ecologically motivated decisions to “let nature take its

course,” the loss of planned views significantly compromises the historic integrity and experiential character of

designed park roads.

The CLR should identify planned views that have been

obscured by plant growth and recommend procedures

to restore intended landscape effects. Potential conflicts

with natural resource agendas may have to be addressed at the park management level. In some cases,

the problem vegetation is comprised of non-native

species, in which case removal will accord with both

natural and cultural resource agendas. When native

vegetation is the primary culprit, historic plans, photographs, and design directives can be mustered to help

make the case for restoring scenic vistas.

Vista management may also include the selective

planting of historically appropriate new vegetation.

Figure 39. Vegetation management is required to maintain

views from historic designed vistas, both along roadsides (A)

and at designated overlooks (B), Blue Ridge Parkway. (Davis

2001)

must be reconfigured, they should be arrayed in

irregular patterns to avoid an artificially uniform appearance, unless local vegetation patterns or historical

precedents suggest alternative approaches. Herbacious

plants and shrubs can further naturalize the transition

between the road corridor and its surroundings.

Planned Vistas

Most park tour roads were designed to provide pleasing

successions of subtly orchestrated views. Variations in

alignment focused attention on scenic highlights,

roadside vegetation was often cleared to open up

extended vistas, and minor pullouts or elaborate

wayside developments were constructed so that

motorists could pause to enjoy the most spectacular

scenic compositions.

Many of these planned vistas have been lost over time

because of unintended plant growth. Expansive

Figure 40. Development on adjacent lands can significantly

affect planned vistas; if scenic easements cannot be enacted,

new plantings such as those visible on the far side of this

highlighted railroad corridor can screen objectionable views.

(Davis 2001)

(A)

(B)
56 L A N D S C A P E L I N E S

Figure 41. Regulatory measures can help to preserve historic

road resources by creating an appropriate balance between

resource capabilities and designated use: (A) Vehicle size limits

enabled Glacier National Park to take a more preservationoriented approach to managing the Going-to-the-Sun Road,

(Davis 1996); (B & C) Yellowstone National Park preserved

the historic “Silver Gate” geological feature by constructing a

bypass for larger vehicles and limiting traffic to one direction,

(Davis 1996); (D) Part of Yellowstone National Park’s historic

Mount Washburn road is preserved as a low-speed unpaved

access road; the upper section is restricted to pedestrian use,

(Davis 1996); (E) This segment of Yellowstone National Park’s

Grand Loop Road has been bypassed and converted for

pedestrian use. (Davis 1999) (A)

(B) (C)

(D)

(E)
HISTORIC ROADS 57

When adjacent land uses have evolved to produce

scenes that are incompatible with park values, new

plantings may be desirable to screen visitors from

objectionable views.

Management Solutions

When modern demands conflict with historic park road

values, managerial solutions often provide preferred

alternatives to irreversible physical interventions. Speed

limits, vehicle-size restrictions, and one-way traffic

patterns can reduce pressures to widen and straighten

historic roads or replace historic safety barriers with

modern designs and materials. One-way traffic patterns

and alternative transportation technologies such as

shuttle buses can decrease crowding while increasing

the effective carrying capacities of park roads and related

facilities. Bypasses can be constructed to accommodate

contemporary demands while preserving exceptionally

important road segments or individual features. In

some cases, it may even be desirable to close historic

park roads to vehicular traffic and transform them into

pedestrian paths or multi-use trails.

The desire to embrace creative approaches should not

preclude careful evaluation of the potential effects of

alternative solutions on historic park road resources.

Some alternative transportation technologies may

require wider, straighter, and more substantial roadbeds

Figure 42. Alternative transportation systems can reduce pressure to alter historic road resources by helping to accommodate

increased demands: (A) Conventional shuttle, Tuolumne Meadows, Yosemite National Park, (Davis 2001); (B) Propane-powered

people mover, Yosemite Valley, (Davis 2001); (C) Proposed light rail vehicle for Grand Canyon National Park, (Grand Canyon National

Park 1997); (D) Modern tour bus designed to resemble classic 1930s park transportation. (Glacier National Park 2004)

(A) (B)

(C) (D)
58 L A N D S C A P E L I N E S

than conventional vehicles, for instance, and bypass

construction may have significant impacts on natural and

cultural resources. The NPS is currently working with

private partners to develop appropriately scaled shuttle

buses based on historical prototypes and experimenting

with various other technologies to lessen the impact of

ever-increasing demands on historic park road resources.

Education and Interpretation

Education and interpretation can play important roles in

creating supportive environments for park road preservation. Park personnel, FHWA staff, and the general

public are more likely to support park road preservation

efforts when they are given sufficient information to

understand the significance of historic park roads and

encouraged to appreciate their distinctive characteristics.

The research and evaluation components of the CLR

can form the basis of internal briefings designed to

educate park staff and cooperating professionals about

historic park road preservation issues. Archival materials, historic film footage, vintage tourist literature

underscoring the popular appeal of traditional park

roads, and contemporary secondary sources and

interpretive graphics such as the drawings produced by

the Historic American Engineering Record’s NPS Park

Roads and Bridges documentation project can be used

to make a strong case for the cultural significance and

responsible stewardship of historic park roads.

Similar material can be used to develop public programs, interpretive kiosks, and educational literature

about park road history and related preservation

concerns. While a few parks have begun to interpret

their historic park road resources, most visitors never

learn about the design concepts, administrative achievements, and construction feats that produced these

magnificent American landscapes.

When visitors and resource professionals learn to

appreciate park road history and understand the

challenges posed by park road preservation, they are

more likely to support measures designed to balance

contemporary desires with long term stewardship

values.

Figure 43. Educating the public about park road history can

build support for stewardship measures: wayside exhibit

providing history of Golden Gate Viaduct, Yellowstone National

Park. (Davis 1996)

CONCLUSION

Historic park road stewardship is one of the most

pressing challenges facing the National Park Service

today. The impressive mileage of historic park roads

that extends throughout the National Park System is

one of America’s most beloved landscape legacies, yet

these increasingly fragile resources must accommodate

ever-evolving demands that were in many cases

unimagined by the system’s original creators. Developing appropriate solutions that reconcile contemporary

circulation concerns with historical values is a complex

process involving many agencies, individuals, and areas

of technical expertise. The CLR can play a vital role in

the development of sound stewardship practices by

providing crucial historical information, conducting

detailed surveys of existing conditions, and proposing

comprehensive strategies for evaluating, treating, and

interpreting these cherished American landscapes.
HISTORIC ROADS 59

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Credits: Reviewers and contributors to this document include: Randy Biallas, Todd Croteau, Susan Dolan, Eliot Foulds, Jack Gordon,

Cari Goetcheus, Lucy Lawliss, Christopher Marston, Beth Savage, Jim Vekasi, Marc Veneroso, and Len Warner.

The mission of the Department of the Interior is to protect and provide access to our Nation’s natural and

cultural heritage and honor our trust responsibilities to tribes.

U.S. Department of the Interior

National Park Service

Cultural Resources

Park Historic Structures & Cultural Landscapes