Scenic Roads Manual
A guide for the protection and enhancement
of our rural roads' scenic qualities.
This document is a rewrite of the Vermont
Backroad Guide published in 1974. It has been enhanced, updated and modified for
San Juan County.
STATEMENT OF PURPOSE
The roads of San Juan County mean much more
to our citizens than simply a way to get from one place to another. Our county roads
are part of the scenic element and rural character that should be preserved. To
this end, San Juan County has prepared this road manual to characterize road design
elements, maintenance guidelines and our over-all road philosophy.
The challenge to county personnel and road design professionals is to protect the
rural scenic quality of island roads and at the same time provide public roads that
are safe for the levels and types of traffic that use them.
This manual is designed to provide the underlying philosophy to guide the County
and other road professionals as well as the general public in formulating ongoing
construction and maintenance programs.
San Juan County Commissioners
One of San Juan County's most valuable resources
is the scenic quality of its rural landscape. The attractiveness is derived from
a variety of elements which compose its land use pattern. Open fields, wooded uplands,
shorelines, farms, villages, and other natural and man-made features provide a visually
rich environment for its residents.
An integral scenic element of the rural countryside is the County road system. These
by-ways are characterized by narrow roadways with diverse and contrasting features
in close proximity. These characteristics provide a unique visual experience when
traveling through the rural landscape. The details of color, texture, and form are
easily recognized. Combined with a sequence of apertures in the roadside canopy,
there exists an intimacy and awareness of the landscape not obtainable on higher
The value of our County roads is found in the unique visual experience they offer.
The appeal to a large tourist population accounts for a substantial portion of the
County's economy. It is from the County road system that the majority of visitors
view the Islands. These roads further define the rural character of the islands,
many of them beginning as farm-to-market or farm-to-dock roads.
Some of San Juan County's roads have been widened, straightened, paved, or otherwise
"improved" to accommodate increased traffic or safety concerns. Often, these modifications
have caused changes to environmental features and in turn have degraded the scenic,
and cultural values associated with a rural road. Such occurrences usually resulted
from an inability to balance safety issues with the scenic qualities inherent to
rural roads. Degradation also occurs because the standards and specifications which
presently guide these modifications often do not consider the relationship of the
rural road to the surrounding features of the landscape.
This guide was prepared with these concerns in mind. Its purpose is to set forth
basic guidelines and examples which will be helpful for the protection, conservation,
and enhancement of the scenic quality of San Juan County's rural roads. The guide
emphasizes that the aesthetic criteria and engineering requirements can be mutually
beneficial. The goal of these guidelines is to implement rural road modifications
which provide user safety, long range reduction of maintenance costs, and a roadway
that is attractively integrated with the roadside and surrounding landscape. When
planning and implementing modifications to a county road, not all of the guidelines
may be appropriate for every situation. The County Engineer and staff will need
to consider other alternatives and proceed with modifications with the public's
safety in mind.
I. PLANNING CONSIDERATIONS
It is very important to carry out planning
as an initial phase of work preceding modification to a county road. During this
time, all factors which can influence the type and extent of modification should
be given consideration. This includes identification and evaluation of 1) operational
requirements, 2) social factors, 3) scenic features, and 4) user safety. Modifications
based on an integration of these factors will lead to an improved county road that
is safe to travel, less costly to maintain, and visually attractive.
A. OPERATIONAL REQUIREMENTS
Modifications to the cross-section and alignment
of a county road are quite often carried out to reduce maintenance costs, prevent
road failure or provide a more efficient roadway for vehicular movement. To fulfill
these purposes, the operational requirements of the roadway must be investigated.
Answering the following questions will be useful in making the proper determinations:
1. Road Function
- Does the road provide vehicular access
to a neighborhood or major destination such as a village/town or ferry terminal?
- Does the road provide only vehicular movement
within a village?
- What type of property access does the
road provide? (limited, partial, full)
- How many homes does it serve?
2. Traffic Characteristics
- What are the existing and reasonably anticipated traffic volumes?
- What type of vehicle will predominately use the road?
- Must the road accommodate heavy trucks and school buses?
- Will bicycles be using the road?
3. Travel Requirements
- What is the safe and reasonable speed at which traffic should travel
along the road?
- Will the road require year-round maintenance?
- Can the road be efficiently cleared of snow?
- What kinds of major maintenance occur on the road?
- Are there perpetual maintenance problems that have not been solved or might affect
- Have there been drainage problems?
B. SOCIAL FACTORS
A further area of consideration during the planning phase is the identification
and evaluation of social factors. While their effects may be thought of as being
indirect, they can have a significant influence on county road modifications. Questions
related to social factors are listed below:
1. Land Use
- What types of land uses are adjacent to the road? (residential, agricultural,
- Will modifications be compatible with these uses?
- Can the proposed modification be carried out within the limits of the
- What are probable changes in land use? (check comprehensive plan, zoning,
and development trends)
- Can the modification be properly completed within the available budgeted
funds? (avoid the "too much for too little" situation)
- Will a more modest and less expensive modification accomplish the same
- Will the benefits, including safety and mobility, justify the level
- What will maintenance costs be after a modification is completed? (improper
grading, lack of erosion control, and inadequate drainage will result in high maintenance
- What other activities use the right-of-way? (horseback riding, hiking,
bicycling, cattle crossing and utilities)
- How will a modification affect these uses and can they be accommodated
in another way within the right-of-way?
C. SCENIC FEATURES
The scenic quality of a country road is primarily related to the variety
of landscape features which comprise the roadside and surrounding landscape. An
objective of any modification should be to protect, conserve, and enhance these
features. Therefore, an essential part of the planning phase will be to locate these
features, recognize their scenic importance, and determine how they will affect
or be affected by a modification. The following list of scenic features and
related questions will be helpful in this process:
- What type of plants grow along the roadside? (ground covers, shrubs,
- What affect will a proposed modification have on roadside vegetation?
- Can excessive removal of vegetation be avoided?
- Can scenic qualities be enhanced by planting or by thinning of unwanted
- What type of terrain does the road travel through? (flat, rolling, steep)
- Are there interesting land forms? (gullies, hilltops)
- Can cut and fill slopes be kept to a minimum?
- Can the roadway and roadside be properly graded and drainage adequately
- Are there unique geologic formations? (bedrock outcrop pings, boulders,
- What will be the influence of rock outcroppings?
4. Surface Water
- Do views of surface water bodies exist or can they be created? (lakes,
ponds, rivers, streams, brooks, salt water estuaries, wetlands)
- Will natural drainage channels be affected?
- What measures will be required to protect streams and shorelines?
5. Unique Natural Areas
- Can views or enhancements of wetlands or salt water marshes be provided?
- What habitats exist along or near the road? (otters, eagles, salmon,
trout, water fowl nesting areas)
- What effects will a modification have on these special areas?
- Is there potential for improving or establishing fish habitats?
7. Main-made Features
- What type of structures and activities typical of a rural landscape
can be seen from the road? (farms, agricultural activity, grazing cattle, villages,
bridges, houses, stonewalls, etc.)
- Can the removal of important roadside structures such as stonewalls,
be avoided? Can views of man-made features be enhanced?
8. Visual Qualities
- Are there features which provide visual diversity and contrast? (spring
flowers, fall foliage, light and shade, openings in roadside vegetation, focal points)
- How does the location of the road affect views of scenic features? (foreground-detail,
center, background-panoramic, position of viewer)
Modifications to County roads are usually pursued to provide a safer roadway
for all users. Adequate attention must be given to current roadway features and
past accident experience to insure all safety issues are addressed. Answering the
following questions will be useful in making the proper determinations:
- What has been the number and severity of accidents over the past 5 years?
- What has been the cause of accidents along the roadway?
- Are there significant fixed objects adjacent to the roadway that need
- Are there conflicts between pedestrians, bicycles or vehicles?
- Are there locations with inadequate sight distance such as driveways,
road approaches or vertical and horizontal curves?
II. GUIDELINES FOR DESIGN, CONSTRUCTION, AND MAINTENANCE
The guidelines set forth in this section stress the importance of protection, conserving,
and enhancing the scenic qualities of a county road. They are also consistent with
good engineering and the necessity to provide a roadway which is safe to travel
and economical to construct and maintain.
A. RELATING ALIGNMENT TO THE LANDSCAPE
A unique visual quality of most county roads is the harmonious relationship
their alignments have with the landscape. Increased volumes of traffic, poor sight
distance, or other operational conditions may often necessitate modification of
an existing alignment. If such a change is necessary, the roadway geometry usually
must become more precise and directional. However, a new alignment should not be
considered a straight line connecting two points. Rather, it should seek the same
qualities of existing alignments by reinforcing and revealing the features of the
landscape. The following guidelines will be useful for relating new alignments with
1. Choose an alignment which blends with the terrain and adjusts to important scenic
2. In most instances, the appropriate alignment will be characterized by curves
which continually adjust to the rolling topography of natural landform. A curvilinear
alignment is visually and functionally preferable to long tangents which cut through
hillsides, leaving steep unsightly and unstable embankments.
3. Where the land is level, or a strong lineal direction is created by landscape
elements, such as a long row of trees or the patterns of fields, the use of a long
tangent may be justified. When using a long tangent, try to direct it toward a natural
or man-made focal point.
4. When climbing a hillside, the roadway should bend to the crest, traversing the
contours, rather than climbing it straight on. However, care must be taken to avoid
hiding a curve or driveway just beyond the brow of a hill.
5. When crossing a ridge, pick a saddle or low area in the top to locate the roadway.
6. Natural and man-made features provide variety and contrast which maintain the
traveler's interest. Whenever possible, alignments should be located to bring the
more interesting features into view.
7. Near the edges of surface water, woods, or a break in topography, use alignments
which echo or emphasize the shape of the edges. However, avoid moving roadways close
to the waters edge as it destroys habitat.
8. When approaching important features, it is preferable to allow a distant view
of the object, curve the alignment away, then bring it close for a contrasting view.
A road which blends with the form and pattern of the landscape is also desirable
from the standpoint of construction and maintenance. Some of the advantages to be
1. Reduction of cut and fill quantities.
2. More efficient utilization of natural drainage channels.
3. Better control of roadside erosion because natural vegetation is preserved.
B. COMBINING HORIZONTAL AND VERTICAL ALIGNMENTS
The combination of horizontal and vertical alignments closely influences
the appearance and safety of a roadway. When alignments are properly coordinated,
a roadway will be visually pleasing and safer to travel. Alignment coordination
primarily applies to major roadways, but the basic principles should also be recognized
as important considerations when altering minor roadways. Set forth below is a partial
list of suggestions to guide the combination of horizontal and vertical alignments.
1. Consistency in the scale of horizontal and vertical elements should be maintained
whenever possible. Small dips and humps should be avoided in what is actually a
uniform grade, and "kinks" should be avoided in what is actually a long curve.
2. The beginning and ending of horizontal and vertical alignments should not occur
in the same location. The beginning of a horizontal curve should generally occur
before beginning a vertical curve and be somewhat longer in length. This provides
a gradual transition between the alignments and prevents one from accentuating the
3. The beginning of a horizontal curve should not coincide with the top of a hill.
This situation is visually deceptive and hazardous, as the quick change in horizontal
alignment cannot be seen by the driver.
4. Avoid dips in vertical alignment before beginning a horizontal curve. This will
prevent the roadway from appearing disjointed.
5. Avoid "broken back" curves (two horizontal curves in the same direction with
a short tangent in-between).
6. When an extremely long grade is necessary, it may be better to adjust the vertical
alignment so the grade is steeper near the bottom of the hill and gradually lessens
as it approaches the crest of the hill. Another alternative is to create an alignment
with intervals of lesser grades.
7. Sight distance requirements vary with the anticipated speed of vehicles. Adequate
sight distance must be provided. This should be checked at all horizontal curves
and crest vertical curves.
The small scale of cross-section elements is an important characteristic
adding to the scenic quality of a county road. This aspect is most apparent in the
width of the traveling surface, its adjacent shoulders, and the close proximity
of the roadside. While these widths may be considered narrow, where traffic volumes
are low, speeds are slow, and meeting and passing of vehicles is infrequent, they
can perform adequately.
Modifications which require widening of the roadway will alter the existing scale
of the county road and consequently its visual impact on the motorist and adjacent
properties. The following considerations should guide the determination of an appropriate
1. Appropriate widths should be determined by the function the road serves as part
of the county road system, operational requirements for safe vehicular movement,
and the characteristics of topography and other physical features (check results
of planning considerations).
2. Consider all elements of the cross-section (traveling surface, shoulders, ditches,
proper grading to stabilize cut and fill slopes, slope rounding, etc.).
3. Can the right-of-way accommodate the cross-section or will approvals be required
from abutting property owners for proper construction?
4. Do not arbitrarily apply a specific standard cross-section to every classification
of county road.
5. Avoid cross-sections which will result in excessive and unnecessary widening
of the roadway.
Recommended widths for roadways with traffic volumes as shown. Higher volume roadways
need additional evaluation.
Over 204 miles of the County's 270 miles of roads have been paved. Typically
a road with a vehicular volume of 300 to 400 vehicles per day should be considered
for paving. At these volumes it becomes difficult and expensive to adequately maintain
a gravel road.
Once a road is paved, it will probably never be returned to gravel surface. Since
the possible consequences of this operation can have a major impact on the rural
quality of a road, the decision to pave or not to pave should be based on a careful
evaluation of all influencing factors.
The evaluation should consider the following points:
1. Does the volume and composition of traffic justify paving?
2. Will the initially high costs of construction be balanced by long-term savings
on the cost of maintenance?
3. Will paving only those stretches of roadway which are difficult be adequate?
4. Are abutting property owners supportive?
5. Is there a need to make geometric or cross-section changes?
E. SHOULDER CONTRAST
If a roadway requires substantial widening and paving, extending the pavement
across the full width of the shoulders should be avoided. The pavement should only
extend across the width of the traveling surface with the shoulders providing a
visual contrast. This delineation will help reduce the visual impact of a roadway's
increased size and provide a more appropriate transition to the roadside. Also,
it will add to traveling safety by clearly defining the limits of the traveling
surface. Appropriate materials for achieving shoulder contrast in rural areas are
1. Gravel or crushed stone shoulders offer good contrast to the bituminous pavement
and do not require a great amount of maintenance.
2. Turf shoulders offer excellent contrast to a bituminous pavement and are quite
fitting for the rural landscape. Grasses used to establish turf shoulders must be
able to endure the effects of salt and compaction (salt comes from snow and ice
3. Natural vegetation which may establish itself on the shoulders will fulfill the
requirement of contrast and also provide natural variety in keeping with the character
of our environment.
F. SHOULDER SECTIONS AND TURNOUTS
The shoulders of a county road are minor elements but serve three basic
purposes. First, they provide lateral support for the traveling surface. Second,
they provide a narrow extension of the traveling surface where vehicles can drive
when meeting or in an emergency. Third, they provide an area for pedestrians, equestrians
Turnouts can provide a substitute for shoulders on lightly traveled roads or on
higher volume roads, to use mailboxes, school bus stops, to observe wildlife, vistas,
or at tops of hills for bicyclists to rest. Spacing these elements at appropriate
intervals along the roadway can often be accomplished with little cost and greater
conservation of roadside features.
Shoulder sections and turnouts should be located and designed in relationship to
the following guidelines:
1. Locations should be clearly visible to the motorist.
2. Intervals between shoulder sections should not be spaced haphazardly, but rather
in a fairly uniform sequence.
3. Relate locations to roadside terrain. Where the grade changes from cut to fill,
suitable locations are often formed.
4. Wherever possible, locate turnouts at points where distant vistas or other interesting
features such as scenic details exist.
5. Provide a gradual transition from the traveling surface to the shoulder section
6. Avoid extremely short lengths of shoulder sections or turnouts.
7. Design to accommodate the intended uses, mailboxes, bicycles, etc.
G. CLEARING AND GRUBBING
The narrow roadside area has a major influence on the scenic quality of
a county road. It contains a variety of features which, because of their close proximity
to the roadway, are extremely visible. Efforts to protect and conserve roadside
features must begin at the earliest phases of construction. Therefore, it is important
that the initial clearing and grubbing work be carried out in a manner which will
maintain the diversity and contrast of natural features comprising a roadside. Following
the guidelines set forth below will be helpful in achieving that objective:
1. The site of a project should only be cleared to the extent necessary for construction.
When important vegetation is to remain it should be clearly marked and fenced if
2. Leave a woodland edge that is uneven and at varying distances from the roadway
to avoid a straight-edged channel.
3. Important vegetation and other landscape features within the limits of construction
that do not obstruct the construction operations should be conserved and protected
4. Wherever possible, and safety allows, specimen trees and other interesting vegetation
growing in close proximity to the roadway should not be disturbed. The minimum setback
from the traveled roadway should be ten (10) feet.
5. If widening needs to be carried out where large established trees or significant
rock outcropping line the roadway, the alignment should be adjusted to one side
or the other so only one row of trees or rock needs to be removed or disturbed.
6. Trees that require removal should be cut as close to the ground as possible and
7. A strip of grass or vegetation should be preserved along shorelines and stream
banks to stabilize slopes and protect against erosion.
8. All debris and unusable waste materials resulting from the clearing and grubbing
operation should be removed from the right-of-way.
9. Whenever the opportunity presents itself, roadways should be moved away from
shorelines, wetlands, or residences.
H. REUSE OF NATURAL MATERIALS
During clearing and grubbing and rough grading operations there often exists
an opportunity to salvage natural materials which can be effectively reused when
restoring the roadside. The materials which should be considered for this purpose
are discussed below:
1. Topsoil is the easiest and most commonly salvaged material. Acceptable topsoil
should be stripped off and stockpiled. In later phases of grading it can be spread
over areas to be seeded, or for use in planting.
2. Plant materials which require removal for construction possibly can be salvaged
to be replanted at a later time. Small plants will be the easiest to remove and
will have the best chance for survival. The roots of plants will need to be covered
with a mulch and kept moist, but the visual effectiveness of natural plants in restoring
the scenic quality of the county road must justify this care.
3. Stones and boulders can be reused to fulfill aesthetic and functional purposes.
If field stones are found they should be reused as a more fitting material for headers
at the end of culverts, as long as they are kept below shoulder elevation. Large
boulders can be used as landscape features in the roadside or even in a nearby stream.
Both stones and boulders can be used as rep-rap material for the stabilization of
shorelines and the banks of streams or fill slopes.
4. Timber, gravel, and sand should always be considered for reuse, but the cost
must be carefully analyzed to determine the feasibility of these operations.
Proper molding of roadside slopes is essential during the grading operation.
Slopes which do provide a smooth visual transition from the roadway to existing
land forms have a pleasing appearance. Slopes shaped in this manner are also required
for effective erosion control, adequate drainage, and reduced maintenance. Some
general guidelines to follow when grading the roadside are set forth below:
1. Where the topography is flat to rolling and the landscape is open, slopes which
are flattened and well-rounded are appropriate. Flattening of slopes to 4:1 (4 horizontal
to 1 vertical) should be carried out.
2. Where the topography is steep, uneven, and wooded, roadside slopes with grades
of 2:1 or 3:1 should be favored to save roadside vegetation. However, check to make
sure the slope is flat enough to be stable.
3. Vary the steepness of roadside slopes to save vegetation and other landscape
4. On areas of extreme cut, which may require easements or more right-of-way, the
use of small benches, stepped down a steep slope, will slow water runoff and provide
excellent locations where vegetation can quickly take hold. It is important to maintain
a slight downhill pitch on these benches to provide adequate drainage.
5. On fill slopes of extreme length, larger benches can be formed to fulfill the
same functions as above.
6. All slopes should be well-rounded to form a smooth transition from the shoulder
edge to the existing grades. Deep ditches with well defined bottoms are required
where drainage or soils are poor. Rounded or shallow ditches are acceptable when
there is little drainage and the soil is free draining.
7. All slopes should be warped by flattening the ends of cut and fill areas. This
will avoid sharp breaks between new and existing grades and result in natural looking
slopes which will more effectively support vegetation.
8. When grading the roadway, avoid disturbing important roadside vegetation and
the creation of deep cuts which expose tree roots and leave steep banks that are
susceptible to erosion and difficult to maintain.
Ditches provide an important function in sustaining quality roads by providing
adequate storm and subgrade groundwater drainage. However, excessively deep or wide
ditches can severely impact vegetation, the rural feel of a road or safety. Several
issues to consider when selecting a ditch section follows:
1. Slopes from the roadway to the ditch bottom should be at least 2:1 on lightly
traveled roads and 3:1 or greater, on other roadways. The shallower pitches will
allow for some vehicle recovery and less potential of a vehicle overturning on higher
2. Ditches should be deeper than the subgrade to allow drainage of rock material.
3. Where ditch construction may impact significant roadside features, short sections
of culvert, curtain drains or shallow or no ditches at all should be considered.
4. Ditches must be constructed to adequately carry the anticipated water flow.
K. EROSION CONTROL
Effective control of erosion is necessary for a county road to be functionally
stable, low in maintenance and visually pleasing. If measures to prevent erosion
are not carried out, runoff will constantly scour slopes; forming channels and depositing
soil in ditches and on the roadway. The result is unsightly and requires unneeded
expenditure of time, effort, and cost to repair.
Control of erosion should start during the initial grading operations. Temporary
measures to control erosion during construction include the following:
1. A rough surface on exposed slopes.
2. A mulch covering (if trees are being removed, investigate the feasibility of
using a chipper for this purpose).
3. The use of checks, dams, berms, matting or other erosion control methods. Hay
bales at the tow of embankments is an easy technique to prevent siltation of streams
Preservation and restoration of roadside vegetation is necessary for the long-term
control of erosion. Plants reduce the eroding capacity of water by cushioning the
impact of rainfall and by holding the soil during times of surface runoff. The following
considerations and guidelines will influence the use and type of plants for erosion
1. The size, steepness, and length of slopes are major factors to be considered.
2. A good seedbed is required to establish vegetation; topsoil, fertilization, and
mulching may be necessary.
3. Seeding to produce a grass cover is the quickest and most commonly used method
to deter erosion.
4. Slopes steeper than 2:1 or which do not support turf, should be planted with
vines, ground covers, or other low growing herbaceous or woody plants.
5. Slopes steeper than 1:1 should be considered for stabilization material such
as jute matting.
L. ROADSIDE STRUCTURES
Structures located in the roadside have a strong visual impact due to their
close proximity to the roadway. Their proper design and location are important factors
to consider. Roadside structures must fulfill functional requirements, but they
should also be characterized by simplicity and visual integration with the landscape.
Set forth below are guidelines for the design and location of the more common roadside
1. Culverts should be located to supplement natural drainage ways and to protect
against erosion. To avoid unnecessary erosion, culverts should be placed a maximum
of every 1000 feet. Fill slopes should not be steepened for shorter pipe lengths.
The use of end sections will give greater length and improve hydraulics. The ends
of culverts should not protrude unnecessarily beyond the grade of slopes and should
be beveled for safety. The ends should be concealed with stones to give a natural
2. Bridges and large culverts should be located so natural stream channels are not
disrupted, thus avoiding extensive rip-rapping and possible washout during times
of high water. Their locations should also allow for a smooth approach of horizontal
and vertical alignments.
3. Guardrails should be provided where safety requires. A minimum two-foot shoulder
should extend beyond the guardrail to provide support, a place for pedestrians and
for aesthetics. Alternatives to the standard guardrails should be considered such
as corten steel, crash walls, New Jersey barriers or timber rails. Bollards should
only be used at pullouts and well removed from the roadway.
4. Electric and telephone utility lines should be located where they will have the
least amount of impact on the view from the road. Poles and overhead lines should
be located as close to the edge of a right-of-way as possible. Avoid lines which
cross the roadway on a long diagonal. Lines should cross perpendicular or at a sharp
angle to the roadway. Curves and low areas are good locations for crossings. Where
lines cross the roadway, poles should be set back from the roadway to screen them
from view and for safety purposes. Low growing plants should be encouraged under
5. Road signs should only be used where necessary for traveling safely. They should
be placed far enough in advance to allow a driver to adjust to the approaching condition.
Try to avoid locations which interfere with views of important features. Non-traffic
related signs should be discouraged though some can provide meaningful information.
M. ROADSIDE PLANTING
The scenic quality of a county road is very closely related to the abundance
and close proximity of vegetation in the roadside. The colors, forms, and variety
of plants provide visual contrast and diversity through all seasons. Plants also
stabilize roadside slopes against erosion. Every effort should be made to protect
and conserve the vegetative resource when modifications are made to a road. However,
removal of vegetation is often necessary, and when extensive, the natural setting
of a road is disrupted. When this occurs, it takes a very long time for natural
vegetation to regenerate. Therefore, the roadside should be planted to restore scenic
amenity, increase safety, and reduce maintenance. Some of the functional uses of
roadside planting are to:
1. Protect against soil erosion.
2. Reduce dust and noise.
3. Protect adjacent landowners.
4. Reinforce roadway alignment by emphasizing changes in direction.
5. Maintain driver attention by providing contrast and diversity along the roadside.
6.. Hide distasteful features from the roadway.
For aesthetic purposes, roadside planting can be used to:
1. Create visual diversity and contrast through variation in size, shape, texture,
2. Modify the sequence of views through varying gaps in the roadside.
3. Maintain scale and perspective with the surrounding landscape.
4. Emphasize or focus important features.
5. Screen visually objectionable objects.
6. Provide habitat for wildlife.
The following considerations should guide the selection of plant materials for use
in roadside planting:
1. Use native plant materials.
2. Use a wide range of vegetation including trees, shrubs, vines, wild flowers,
ferns, and ground covers.
3. Use plants which are suited for the physical characteristics of the site, i.e.,
soil type, sun, shade, moisture, etc.
4. Consider the appropriate methods for transplanting.
5. Consider plant hardiness. Plants growing nearby will give an indication of species
that might be suitable.
6. Avoid plants which require careful treatment, maintenance or wet climate.
7. Avoid plants which are easily susceptible to insects and diseases.
8. Trees that are weak and might easily be broken by wind or snow loads should be
placed away from the roadway.
9. Use small sized plants which can be easily removed from their natural site and
transplanted with greater chance of survival.
10. Avoid noxious weeds.
When planting the roadside, it is important to relate the arrangement and location
of plants to the natural patterns of existing vegetation. The following guides will
be helpful to achieve compatible relationships:
1. Plants should not be planted in geometric or uniform patterns, nor randomly scattered
in a meaningless pattern.
2. Plants should be informally grouped in masses and clumps, with attention given
to combinations which will provide diversity and contrast.
3. Space trees so when mature they will be proportional in size with surrounding
4. Arrange plants so their edge is uneven and closer to the roadside in some locations
and further away in others.
5. Wildflowers, ferns, ground covers, and low growing plants should be placed close
to the roadway so their detail will be easily visible.
6. At various intervals, plant shade trees, evergreens, or other interesting species
to provide focal points along the roadside.
7. Plant low height vegetation versus shrubs and trees next to the roadway to maintain
safe sight distance.
8. If a tree-lined effect is appropriate, space the trees at uneven intervals and
with slight variations in distance from the edge of the roadway.
N. VEGETATION MANAGEMENT
Along many county roads there exist numerous opportunities to greatly enhance
scenic quality and improve operational safety through the proper management of roadside
vegetation. It is important to note that the gains from improving some sites may
not outweigh the costs of selective thinning and clearing. Therefore, efforts should
be concentrated on those roadside sections where the maximum gain in scenic value
and operational safety can be created.
When carrying out vegetation management for these purposes, the basic visual requirement
is that the roadside should have a natural appearance in harmony with the surrounding
landscape. The practices listed below should be carried out with that objective
1. On curves with poor sight distance, thinning and clearing of vegetation may improve
views so alteration of the alignment will not be necessary.
2. Vegetation near the roadway should not consist of weak-wooded or dead trees that
constitute a blow-down hazard or are visually unattractive. These trees should be
trimmed or removed to encourage the growth of hardier, disease resistant vegetation.
leaning trees, whether on public or private property, should be removed.
3. Cut vegetation close to the ground to hasten decay, reduce fire hazard , and
to avoid the immediate unsightliness of forest cuttings.
4. The edge of woods should be maintained as an irregular line and generally follow
the contours of the roadside.
5. Retaining understory shrubs in masses will provide a variety of spring and fall
colors and a transition in size from ground covers to trees.
6. Thinning roadside vegetation adjacent to open fields and retaining it close to
the roadway in wooded areas will help to vary the sequence of apertures along the
7. Stands of large trees or smaller interesting trees such as maples or oaks may
be exposed to provide visual accents.
8. Selective thinning of vegetation at varying intervals along a densely wooded
roadside will add visual interest by allowing views to penetrate the forest growth.
9. Mowing within the first 4 feet from the traveled roadway should occur 2 to 3
times per year to protect sight lines and avoid grass fires. Beyond the first 4
feet from the traveled roadway should be mowed or brushed at least once a year.
Where mowing is conducted to control unwanted woody vegetation, it should be repeated
only every second or third year or more often where the vegetation creates a safety
10. Selective thinning and clearing of roadside vegetation should be carried out
where the opportunity exists to create distant panoramic views of the landscape.
Property owners should be encouraged to open vistas and allow territorial or unique
11. Trimming of branches should be done close to the tree trunk and treated where
12. Tree trimmings and other debris may be chipped and mulched alongside the roadway