The essence of beautifying roadways
Roadway beautification once meant planting a few trees and flowers. Today, it means much more. Cities and counties are combining a diverse palette of plant materials, architectural features and new construction techniques to meet functional, aesthetic and environmental requirements. This process creates tremendous opportunities and challenges for landscape designers, contractors and maintenance personnel.
Programs for roadway beautification vary, and many factors influence their development. This article addresses how important the landscape is to the visual quality of highways, with an emphasis on urban-suburban roadways. It includes design and maintenance considerations, providing practical knowledge for designing and maintaining roadway landscapes.
Ever wonder if finding Oz would have been as intriguing to Dorothy if the Yellow Brick Road was just a paved surface with no greenery on the side? Notwithstanding potent poppies, the trees and plants along any road make the package more palatable, whether it's a major roadway or a simple path home.
Although the initial goal in all projects is to mitigate the intrusiveness of the road, the factors that determine a designer's effectiveness can differ a great deal. Highway beautification preserves and protects the natural environment, and urban projects create a sense of place, stimulate growth and foster community support for new and improved roadways.
Our nation's highways often traverse pristine environments. Careful design, construction and maintenance should minimize the impact of highway construction on adjacent natural habitats that support plants and wildlife.
Urban roadways do more than carry motorists into a business center or a neighborhood--they instill a "sense of place" for the community and link activity areas such as parks, neighborhoods and shopping districts. Under this concept, roadway engineering design and landscape architecture combine to create a safe, convenient transportation facility that also helps to promote and establish the community as a healthy and vibrant place to live.
Project development To be most effective, roadway beautification design must consider initial costs and ongoing maintenance. You can achieve a striking visual effect without incurring high installation expenses and requiring extensive staff time. The key is to base design decisions on maintenance requirements and an overall vision for the project.
Each project should begin with a site visit and a design analysis. Before beginning the design, you should consider doing the following steps at a minimum:
*Evaluate adjacent developments and the roadway's relationship to them *Build public support and consensus through idea-generating workshops or other meetings with key civic leaders, businesses and the public *Identify existing trees, plants and other natural elements you want to preserve and consider applicable protection practices *Locate existing utility corridors *Determine targeted levels of appearance and the associated maintenance requirements *Evaluate water use, cost and availability for irrigation.
In your analysis and planning, remember that roadway beautification may need to take into account various users--abutting property owners, motorists, bicyclists and pedestrians. Roadway beautification features should not obstruct views or create unsafe areas for pedestrians and bicyclists.
Design considerations Achieving economic installation and maintenance costs should be a prime factor in design decisions. Landscape architects should consider optimum spacing of trees, shrubs and ground cover, maintain site distances for motorists' safety and minimize the use of materials that require high long-term maintenance.
Roadway projects challenge landscape architects to create a visual impact within a linear area. Landscape architects can achieve this effect by concentrating efforts on spots along the roadway that merit special treatment, such as entry points to a community, business district or neighborhood. Although the entire corridor will require some type of ground cover, trees, water features and other amenities will create a greater visual impact if grouped together.
Another consideration is that plants grow at different rates. A new landscape may need years of growth before creating the full and lasting aspects of the visual impact you desire. The need to achieve immediate results may warrant the use of larger plant material. Smaller plant materials may be appropriate when a longer "grow-in" period is acceptable. The optimal size for plant material at the time of installation varies from project to project.
Material should offer visual interest during every season. You should select trees and shrubs with good spring and fall color for interesting winter characteristics. The use of flowers should involve early, mid- and late-season varieties to provide color throughout the year. Massings of perennial plants and grasses can help reduce mowing and maintenance costs, while providing more plant color and enriching the visual texture of the roadway landscape.
Safety is critical for roadway projects, and beautification efforts can play a role in this area. Several studies have shown that roadways that are visually appealing without being distracting sometimes can reduce speeds and potential accidents.
The Lynnway/Carroll Highway in Lynn, Mass., designed by HNTB (Kansas City, Mo.) exemplifies the considerations described above (see photo, opposite page). The parkway landscape developed for the 2-mile project visually unites the diversified features of the abutting land uses. Medians and traffic islands feature landscaping, and the design incorporates a new signage system to enhance traffic management and improve driver safety (see photo, page 80). The installation of hundreds of new trees provides instant impact while requiring minimal maintenance.
Olathe, Kan., provides an urban example. This thriving suburb of Kansas City, Mo., has embraced roadway beautification as a key ingredient to economic growth. Two current roadway projects designed by HNTB will contribute to this effort.
The first project involves a quarter-mile corridor from an interstate to a major roadway that will serve as the primary gateway to Olathe's emerging retail and entertainment area. The corridor's design features extensive plantings and ornamental fencing along the right -of-way, which serves to funnel views to the roadway and to the landscaped median. A water feature with four 12-foot-high waterfalls and a sloped water channel will welcome and orient motorists to this important commercial area. The feature is located in the median and uses native limestone and elevated planters to reflect native stone ledges with cascading plants as seen in roadway and stream cuts in this community located on the edge of Kansas' prairies. HNTB's designers worked closely with city staff in the design of the water feature and landscape plans to create an environment that will be visually appealing, economical and easy to maintain.
As part of this project, the city also targeted for beautification a second 2-mile-long, major arterial roadway consistingof a 30- to 40-foot-wide median dividing four to six lanes. A corridor analysis revealed that an extensive network of underground utilities precluded plantings in the right of way. The city wanted a design that would provide a significant visual impact, using only the median area. The eastern limit of this project also serves as a gateway to the city. HNTB designed a low prairie-style native-stone water feature to carry the city logo and provide visual interest. The design includes a series of waterfalls and a linear planter with low bubbler jets. Linear planting beds contain massings of trees, shrubs and ground cover. The beds are not continuous but occur at predetermined intervals to create visual rhythm to motorists as they move through the corridor. Elevated beds using fertile topsoil mixed with recycled organic material have a maximum slope of 3-to-1.
Maintenance considerations Initial funding availability and ongoing maintenance budgets and staff are significant design considerations. A well-designed roadway landscape can minimize maintenance. You can minimize mowing and watering by locating trees in continuous beds or "drifts." Placing a layer of wood mulch or other organic mulch material will serve to conserve moisture and choke out potential weed growth until the plants are established (usually 2 to 3 years). Applying a pre-emergence chemical to the soil before mulching also will minimize weed growth. It is best to plant low shrubs or ground cover in the beds containing the tree plantings to minimize long-term maintenance and maximize visual quality and seasonal color.
Highway maintenance, especially for interstate areas, usually involves mowing and trash pickup. However, many states and local areas have embraced the introduction of wildflowers and native grasses as part of the highway landscape.
Wildflowers provide visual interest and increase habitat for some animals and insects. The flowers can be a cost-effective way to improve the visual quality of roadways, especially when combined with other plant materials and site furnishings. Wildflower programs do require some maintenance, particularly in the first few years.
Predetermined mowing patterns and a regular mowing schedule allow for more efficient use of maintenance personnel.
Plant material selected for roadway locations should be easy to maintain. Avoid those that require extensive watering to thrive. Buffalograss or hybrid bermudagrass are good choices for warmer climates, although these varieties are not as dark green as tall fescue and bluegrass used in northern climates. Lower water use for warm-season turfgrasses may be a trade-off for appearance.
Ground covers, such as Vinca, ivy, Ajuga or wintercreeper and daylilies are attractive choices. Liriope and daylilies fill in quickly, require little water and offer dramatic seasonal color. However, ground covers may collect trash until they form a dense vegetative mat. You can mow most ground covers in early spring to remove trash and dead vegetative material.
It's also important to use plants and landscape material indigenous to a geographic area whenever possible. Not only are they usually more economical because they are readily available, but maintenance personnel usually are more familiar with their installation and maintenance.
Simplifying mowing areas and patterns as much as possible also offers benefits. In Olathe, HNTB used a landscape concept that alternates groupings of ornamental, evergreen and shade trees to create an interesting visual rhythm. At the same time, the grouping of trees facilitates grass cutting, providing larger, open areas for mowing. This arrangement minimizes trimming and allows the use of mowers with larger cutting decks, which requires less maintenance time.
Roadway maintenance options Communities can gain help with maintenance by instituting Adopt-A-Highway or similar programs. Interested volunteers commit to being responsible for trash pickup, mowing and other simple maintenance activities. Contract maintenance services or staff can concentrate on areas that require more expertise.
Cities often contract with maintenance companies for their roadway improvements. The designer can prepare a checklist for recommended routine maintenance as a base document for establishing a level of desired maintenance and for estimating projected costs for mowing, irrigation and plant materials. A maintenance plan serves to establish those activities the designer feels are necessary to maintain the intended appearance and health of the new roadway improvement.
The bottom line Beautiful roadways can be affordable and easy to maintain. Designers are working with maintenance staff to achieve the desired visual qualities of the landscape with minimal maintenance. The results are projects that enhance scenic quality, reflect an area's economic health and protect the environment.
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