Louisiana Administrative Code › Title 70 - TRANSPORTATION AND DEVELOPMENT › Part I - Highway Construction › Chapter 3 - Roadside Vegetation Management › Section I-313 - Landscaping

Current through Register Vol. 50, No. 6, June 20, 2024
A. General
1. Highway landscape design should begin with
				an analysis and the inventory of the landscape features in order to identify,
				evaluate and locate the features to be conserved, further developed and/or
				incorporated in the highway corridor.
2. Careful and proper landscaping of the
				right-of-way should result in the conservation, enhancement and effective
				display of the urban and rural countryside through which the highway passes. A
				properly landscaped highway will conserve the historical features and natural
				landscape assets while improving the aesthetic and functional quality of the
				highway.
3. There are two general
				classes of vegetation along highways: turf, such as grasses and legumes, and
				taller growing types consisting primarily of woody plants which are shrubs and
				trees. This Section is devoted to the planning and design of the taller growing
				plants as seen against the foundation of turf. Woody plants create a
				three-dimensional effect in the landscape and require special design
				considerations. Natural growth that exists may provide part or all of the
				desired planting effects in rural areas. Where possible, the retention of
				desirable natural existing growth is extremely important and requires
				consideration early in design. Planting is important along highways on new
				location and many times it may be more important along reconstructed highways
				on existing location because of restricted right-of-way and adjacent
				development.
4. The motorist should
				be able to view complete vistas and changing scenes in scale with the travel
				speed. Widely spaced plantings of individual trees or shrubs create a spotty
				and disturbing effect. Massed plantings are the form and texture of the
				landscape viewed at highway speeds. Tree plantings should be set back from the
				traveled lanes, not only for safety but also to insure spatial continuity and
				the strong visual effect of a wide turf area between pavement and plantings.
				Generous sight distance must be maintained at all times. The plants used must
				be capable of growing relatively well with minimum maintenance to serve their
				purpose under the highway conditions they may encounter.
5. Design and choice of plant materials vary
				considerably from region to region. Rural locations may only require
				supplementing existing growth with small sized new plants and planting for
				special functions while the urban and suburban highway may require extensive
				plantings with larger sized plants.
6. Planting designs should be created in
				accordance with the requirements of the highway and serve a justifiable
				purpose. They should be planned objectively on a broad scale before
				consideration is given to the actual selection of plants to be used. Their
				composition should be pleasing and coordinated with the total highway
				environment with safety being the most important consideration.
7. Planting plans should be clear, concise,
				easily understood and presented on drawings separate from the highway
				construction plans. The plans should indicate type of adjacent land use,
				topographic features, such as slope limits and utility installations in
				addition to the location of plants and their area of occupancy at maturity. A
				plant list should also be included in the plans. This will provide information
				concerning the species, size, condition, fertilizing requirements and other
				pertinent general notes which may apply. The latest and best planting
				techniques should be used along with top quality plants. Specifications for
				nursery stock, planting and other types of landscape construction should be
				clear, concise and describe the quality of work desired.