Landscape architecture may not be the first priority that comes to mind when planning transportation projects, but it does have a significant role in all stages of planning and public opinion. While many of the design principles that go into landscape architecture for transportation projects are similar to other project types (buildings, urban design, etc.), there are considerations specific to highways.

Public Experience

Viewing a landscape at 60 mph is very different than leisurely walking through it. The plant materials used and landforms constructed should blend into existing conditions to enhance the natural beauty of the road, but not be distracting to drivers. Safe sight distance for drivers, mowing and maintenance care, and multi-modal transportation also need to be considered.

Plant Selection

Since blending landscape design into the existing environment is essential in most roadway projects, plant selection becomes an opportunity to utilize native species that occur in the existing conditions. At the same time, due to the volume of plant material used, availability and maintenance can be difficult. Plants undergo exposure to wind, salt, and variable soil conditions, many of which cannot be predicted in planning. The location of plant materials, and agency responsible for maintenance, may mean that plants must be hardy selections to survive more adverse conditions.

Design Elements

There are particular design elements that are only found in highway and road construction, including noise barriers and bridge abutments, which must be given special consideration when designing landscapes. Where the road is constructed lower than the surrounding environment, the noise barrier is at or near existing grade and the land slopes to the road. This provides a large area to landscape with, allowing for a mixture of trees, shrubs, perennials, and grasses—giving the opportunity to create a striking visual enhancement. Landscaping at bridge abutments can enhance the architectural design of the bridge. However, materials that will not grow over the bridge onto the roadway must be carefully selected. Since roads can be incompatible with adjacent uses, additional screening to and from the road will likely occur between adjacent businesses, homes, and other properties.

Environmental Considerations

Since transportation projects have a high level of public participation, environmental commitments are often involved in the decision-making process. These committees may include stream and wetland restoration, reforestation, and habitat protection. Given the physical expanse and long time frame of these projects, commitments may span multiple jurisdictions and environmentally sensitive locations with requirements from multiple review agencies.

While landscape architecture may seem like the final step of transportation planning and design, there are many considerations that need to be made during the beginning stages. A successful project is one that has been coordinated between multiple partners and agencies, producing a final product that was kept in mind during the entire process. Every highway that looks like it is set naturally into its surrounding landscape has been carefully planned to appear that way, minimizing impacts on its surroundings.