Design roadsides to maximize sustainability and livability benefits through context-sensitive design solutions. Sustainable design solutions are those that consider balanced and long-term benefits to social, economic, and ecological well-being.
Sustainable landscape architecture designs:
- improve safety for workers and travelers
- improve the quality of the public realm
- conserve water and natural resources
- sequester carbon and improve ecosystem resiliency
- address fire safety
- preserve or improve visual quality and aesthetics
- reduce unnecessary maintenance activities
- employ cost-effective solutions
- consider life-cycle costs and benefits.
Attention should be given to the following considerations:
- Worker Safety. Design roadsides for the safety of highway workers and the public by considering the following:
- Site new roadside features outside of the clear recovery zone and away from gore areas and driver decision points.
- Provide access for workers including maintenance vehicle pullouts, maintenance access roads and gates.
- Design solutions that facilitate the use of mechanical equipment to reduce worker activities on foot including the use of new technology.
- Select design solutions that eliminate maintenance activities.
- Relocate existing roadside elements to accessible areas outside the clear recovery zone or to protected locations.
Incorporate the above design considerations when designing roadsides. For example, provide access gates from local streets and frontage roads for maintenance personnel; coordinate with District Maintenance managers for preferred access points. Provide paved maintenance vehicle pullout areas away from traffic on high-volume highways where access cannot be made from local streets and roads. Consider providing maintenance access roads to the center of loop areas or other open, flat areas. Pave narrow areas and areas beyond freeway gore entrances and exits to reduce the need for maintenance. See Index 504.2(2) for contrasting surface treatment guidance.
- Maintainability. Field observations with maintenance personnel should be performed during project development, Pre-PID through PS&E. Ongoing communication between designers, landscape specialists, landscape maintenance personnel, and construction inspectors will ensure that maintenance concerns are addressed.
Design roadsides to minimize routine and ongoing roadside maintenance and to accommodate:
- graffiti control and removal.
- homeless encampment removal.
- mowing and weeding.
- litter, debris, and/or dead vegetation removal.
- exotic or "volunteer" vegetation control.
- pesticide and/or fertilizer application.
- pruning or removal of vegetation.
- irrigation and waterline break repair.
- irrigation scheduling for water budgeting.
- replacement of plants and repairs to inert materials.
- maintenance requirements of permanent stormwater pollution prevention treatment BMPs.
- Livability. Livability describes the degree to which the built environment improves human quality of life. Designs that improve livability are those that consider how the public realm and roadside can support travel and local community goals. Livable transportation systems connect people to opportunity and promote public health and safety, ecological quality, economic development, community vitality, social equity and interaction, multimodal travel, sense of place, and human health.
Create a state highway public realm through designs that improve community visual quality, provide inviting public spaces, and encourage active transportation. Encourage and support Landscape Architecture Administered Facilities such as Transportation Art, Gateway Monuments, and Community Identification to enhance livability. Livable roadside facilities often include:
- connectivity of active transportation and complete streets facilities.
- site furnishings such as benches, bicycle racks, and trash and recycling receptacles.
- Street trees and other vegetation that provide shade and a separation for vehicles and pedestrians
- Visual Quality and Aesthetics. Design roadsides to integrate the facility with the adjacent community or natural surroundings. Buffer objectionable views of the highway facility from adjacent homes, schools, and parks. Soften visual impacts of large structures and graded slopes. Screen objectionable or distracting views. Frame or enhance good views. Provide visually attractive roadsides, entrances to communities, and mainstreets.
- Ecological Function. Design roadsides to incorporate native and climate appropriate vegetation, with attention to supporting pollinators, and facilitating stormwater infiltration on- site. Improve soil with compost to build healthy soils, sequester carbon and mitigate greenhouse gas emissions.
- Water and Resource Conservation. Roadsides must comply with State water conservation requirements including the Model Water Efficient Landscape Ordinance (MWELO). Comply with local water ordinances. In addition, design landscapes to conserve water by designing efficient irrigation systems and appropriate planting designs that:
- use non-potable or recycled water.
- use soil amendments to build healthy soils and increase water holding capacity.
- use drought tolerant, climate appropriate plants.
- use large groupings of spreading plants.
- use topical mulches to reduce evapotranspiration.
- use automated "smart" irrigation controllers.
- use moisture, wind, and rain sensors.
- use point source irrigation and tree well assemblies.
- minimize use of overhead irrigation.
- Fire Safety. Consider the risk of fire when designing landscape architecture projects. Consider the following in high fire risk areas:
- Create fire-resistant zones and defensible spaces to minimize the spread of wildfire
- Remove dead and dying vegetation
- Minimize or eliminate vegetative fire ladders
- Select plants with low sap or resin content and high moisture content
- Select plants with prostrate growth and minimal fuel volume
- Select nonflammable or low fuel inert materials for ground surface cover
- Cost-effectiveness. The design should maximize short and long-term benefits for the costs involved by:
- Optimizing scheduling, performance, constructability, maintainability, and material life cycle costs.
- Specify commercial/industrial quality materials and methods to improve cost- effectiveness.
- Utilize long-lived plant species.
