California Department of Transportation

Introduction to Caltrans Landscape Architecture

This Introduction to Caltrans Landscape Architecture website provides a brief yet comprehensive look at the roles and responsibilities of Transportation Landscape Architects, Landscape Associates and Landscape Technicians at the California Department of Transportation (Caltrans).  Whether you are an experienced Caltrans employee, a new hire, or someone considering a future position with Caltrans Landscape Architecture, this website will provide you with a broad understanding about what landscape architects do at Caltrans.



Guidance Manuals and Other Tools

Transportation Goals and Community Values

Multimodal Mobility

Scenic, Aesthetic, and Environmental Resources

Highway Planting

Roadside Management

Roadside Facilities


Our goal is to integrate the transportation facility with its setting, creating a visually pleasing travel experience for all who live, work, and travel in California. Landscape Architects are licensed design professionals that develop safe, functional, and beautiful transportation corridors.  Landscape Associates, Ranges A, B, and C share many of these same responsibilities but are not licensed by the state. Landscape Technicians provide technical support for Landscape Architects and Landscape Associates but do not hold a degree in landscape architecture.  Together as a team we play a vital role in providing a multi-modal transportation network that coexists harmoniously with the natural and built environment. 

Integrated Highway Facility

Transportation Landscape Architecture strives to integrate the highway facility
with the surrounding context as on Route 280 in San Mateo County.


Landscape architects with Caltrans provide expertise in a specialized area of the profession – Transportation Landscape Architecture.  We focus on enhancing the environment and people’s quality of life through transportation improvements.  As landscape architecture specialists and transportation generalists, we promote design solutions for all modes of transportation that emphasize safety, stewardship, environmental protection, aesthetic and scenic quality, and the integration of community values into transportation projects.

Landscape architects provide Project Development Teams (PDTs) with expertise in the planning, design, construction, maintenance and operation of transportation system improvements that:

  • Maximize traveler and worker safety.
  • Balance safety, mobility, maintainability and economic needs with adjacent land use and aesthetic, environmental, scenic, cultural, and community values.
  • Preserve and enhance the environment through sustainable solutions.
  • Balance the needs of motorized and non-motorized users.
  • Contribute to improving the quality of life for all Californians and visitors.

Landscape Architect

Landscape architects are licensed design professionals whose responsibilities include the
development, management, and operation of California’s state roadsides.


Although the focus of this website is Landscape Architecture in the Project Delivery Design function, Caltrans landscape architects are a diverse group of professionals whose skills are applied in many different functional offices and divisions throughout Caltrans Headquarters and the twelve district offices including: Environmental, Stormwater, Project Management, Office Engineer, Construction, Maintenance, Permits, and Local Assistance.

Landscape Architecture Program Responsibilities

  • Preserving and restoring natural ecosystems
  • Revegetation
  • Erosion and stormwater pollution control
  • Highway planting and irrigation
  • Visual impact assessment
  • Landform grading
  • Concrete barrier and wall aesthetics
  • Maintenance worker safety
  • Vegetation control
  • Safety roadside rest areas and vista points
  • Park and ride lots
  • Corridor master plans
  • Context Sensitive Solutions
  • Main streets and livable communities
  • Complete Streets
  • Traffic calming
  • Bicycle/pedestrian mobility
  • Americans with Disabilities Act
  • Transportation art
  • Gateway monuments and community identification
  • Scenic highways
  • Resource conservation
  • Water management
  • Landscaped freeway classifications
  • Research and new technology in Transportation Landscape Architecture

Landscape architects are also uniquely skilled in developing sketches, drawings, and photo simulations of proposed transportation improvements that are not only useful for the planning and design process but also serve as valuable communication tools when working with state and local agencies, the public, and other stakeholders.

Communicating design concepts through graphics.

Landscape architects have expertise in communicating design concepts through graphic illustrations. 
This example is from the 215/91 Corridor Master Plan in Riverside.


Guidance Manuals and Other Tools

Having the right tools is critical to job success.  Caltrans standards, policies, guidance manuals and websites are key tools that guide landscape architects through the planning and design process.  The most critical of these reference tools include:

  • Highway Design Manual
  • Project Development Procedures Manual
  • Landscape Architecture PS&E Guide
  • Landscape Architecture Program (LAP) Website
  • Standard Environmental Reference on the Division of Environmental Analysis’s (DEA) Website

Reference is made to these tools throughout this websites to identify where the reader can go for additional information on the topics discussed.  Following is a brief description of these reference tools and how they are relevant to the Landscape Architect, Landscape Associate, and Landscape Technician during the project development process.


Highway Design Manual

The Highway Design Manual (HDM) establishes uniform design standards to accomplish Caltrans’ highway design function.  It is Caltrans’ main source of guidance on highway design.

The most relevant chapter to the landscape architect is Chapter 900 “Landscape Architecture”, but there are several additional chapters that provide standards for the landscape architect.  The chapters and sections listed below are also pertinent for roadside design activities. 

HDM Subject (Ordered Alphabetically by Topic) Chapter/Topic
Application of Design Standards 80
Bicycles 1000
Clear Recovery Zone 309.1(2),902.2(2)
Control of Noxious Weeds 110.5
Gore Paving - Contrasting Surface Treatment 504.2(2)
Highway Planting Standards and Guidelines 902
Irrigation Crossovers 706.3,4,5,6
Irrigation Guidelines 902.4
Landscape Architecture Definitions 62.5

Landscape Architecture- General 901
Noise Barrier Aesthetics 1102.6
Pedestrian Facilities 105
Planting Guidelines 902.3
Project Development Philosophy 81.1
Roadside Treatments (Roadside Management) 706
Safety Roadside Rest Areas (SRRA) 903
SRRA Site Selection 903.3
SRRA Structures 903.7
Scenic Values in Planning and Design - Aesthetic Factors 109.3
Side Slope Standards 304.1
Slope Treatment Under Structures 707
Trees on Conventional Highways 902.3(4)
Vegetation Control 706.2

Vista Points 904
Water Pollution Control 110.2

The HDM is accessible through the Headquarters Division of Design website. 


Project Development Procedures Manual

The Project Development Procedures Manual (PDPM) addresses policies and procedures, roles and responsibilities, transportation planning, and procedural standards and guidelines applicable to the project development process from project initiation through construction.  For an excellent and quick view of the entire project development process, see How Caltrans Builds Projects.  Then consider taking the online course, Introduction to the Project Development Process.

The policies and procedures that guide landscape architects in their responsibilities through the project development process are primarily found in Chapter 29, “Landscape Architecture”.  Provided are definitions, general policies, roles and responsibilities, the project development process, and policies and procedures on topics such as highway planting, safety roadside rest areas, vista points, aesthetics, transportation art, community identification, and gateway monuments.

The chapters and appendices listed below are also pertinent to landscape architectural work. 

Chapter 29/Sec 2/Art 2

PDPM Subject (Ordered by Chapter/Appendix)


Roles and Responsibilities Chapter 2
Involvement of Caltrans Functional Units - Landscape Architecture. Chapter 3/Sec 12
Project Development Team Chapter 8/Sec 4

Community Involvement Chapter 22
Landscape Architecture - General Chapter 29/Sec 1
Highway Planting - General Policies Chapter 29/Sec 2/Art 1
Highway Planting by Others Chapter 29/Sec 2/Art 3
Project Development Process (Landscape Architecture) Chapter 29/Sec 2/Art 4
Safety Roadside Rest Areas Chapter 29/Sec 3
Vista Points Chapter 29/Sec 4
Aesthetics Chapter 29/Sec 5
Transportation Art Chapter 29/Sec 6
Community Identification Chapter 29/Sec 8
Gateway Monuments Chapter 29/Sec 9
Preparation Guidelines for Project Report (HP&R)

Appendix D

Preparation Guidelines for Project Study Report (HP) and
Project Study Report Data Sheet (HP&R)
Appendix E
Preparation Guidelines for Project Report Appendix K
Preparation Guidelines for Project Study Report Appendix L
Scoping Tools Appendix L Chapter 6
Preparation Guidelines for Project Report (SRRA) Appendix M
Preparation Guidelines for Project Study Report (SRRA) Appendix X
Project Scope Summary Report (Roadside Safety Improvements) Appendix Q

Cost Estimates Appendix AA
Landscaping (Fact Sheet/One Liner, Design Intent Statement) Appendix EE

Access the PDPM through the Headquarters Division of Design website.  


Landscape Architecture PS&E Guide

The Landscape Architecture PS&E Guide (Guide) provides guidance specific to preparing planting and irrigation plans, specifications and estimates.  In addition, the Guide provides design best practices and time saving tools such as checklists, design do’s and don’ts, and conversion tables.  The information in the Guide will help ensure that the plans, specifications and estimates for highway planting projects are prepared to a quality standard that is biddable and buildable.

The online version of the Guide is accessible on the Landscape Architecture Program’s (LAP) website.

Landscape Architecture Program’s Website

The LAP website offers a comprehensive gateway into the broad scope of Landscape Architecture at Caltrans, including information about:

  • Standards, Manuals, Policies and Procedures
  • Design Information Bulletins and  Design Memos
  • Highway Planting PS&E
  • Erosion Control Toolbox
  • The Roadside Management Toolbox
  • Safety Roadside Rest Areas
  • Context Sensitive Solutions
  • Highway Barrier Aesthetics
  • Scenic Highways
  • Transportation Art
  • Blue Star Memorial Highways
  • Gateway Monuments and Community Identification
  • Landscaped Freeway Classifications
  • Water Conservation
  • Research and New Technology

This LAP website also provides contact information for the Headquarters LAP staff and the District Landscape Architects.

Standard Environmental Reference

The Standard Environmental Reference (SER) is the comprehensive resource for the development of environmental documents required for transportation projects. It includes the Caltrans Environmental Handbooks, detailed information on National Environmental Policy Act (NEPA) and California Environmental Quality Act (CEQA) documentation, and provides outlines for developing environmental documents.

The Caltrans Environmental Handbook Volume 1 “Guidance for Compliance”, Chapter 27 “Visual and Aesthetic Review” is the landscape architect’s primary resource for guidance on performing quality Visual Impact Assessments (VIA).  VIAs are performed by landscape architects during the Environmental Document process to document and assess the visual impacts caused by a transportation project.  Additional discussion on VIAs is provided in the section on “Aesthetic, Environmental and Scenic Resources” of this website.

The SER is available through the Division of Environmental Analysis’s website. 


Transportation Goals and Community Values

California residents consistently list traffic congestion as one of their top concerns in regards to their overall quality of life.  Addressing congestion and improving mobility are primary concerns of Caltrans. This is reflected in Caltrans’ Mission Statement which captures the very essence of this responsibility:

"Caltrans Improves Mobility Across California"

Improving Mobility Across California


Caltrans strives to be the highest performing transportation agency in the country.  In pursuit of this mission, we continue to build a talented and diverse team and strengthen ties with our partners. To keep California moving, Caltrans is committed to these goals:

  • Safety – Provide the safest transportation system in the nation for users and workers.
  • Mobility - Maximize transportation system performance and accessibility.
  • Delivery - Efficiently deliver quality transportation projects and services.
  • Stewardship - Preserve and enhance California’s resources and assets.
  • Service - Promote quality service through an excellent workforce.

The efforts made by landscape architects to address driver and worker safety, pedestrian and bicycle mobility, scenic quality preservation, aesthetics, erosion control, and resource conservation contribute to the achievement of these goals. 

Transportation goals are addressed in balance with community values.  It is Caltrans policy to follow a collaborative, interdisciplinary approach with stakeholders to achieve this balance through a process called Context Sensitive Solutions (CSS).  CSS is a process of early and continuous stakeholder involvement to solve transportation problems.  The process defines a collective vision that not only solves transportation problems but also reflects and enhances community and cultural values and is compatible with the natural and built environment.  CSS offers an opportunity for consistent, creative, and collaborative problem solving that improves a project’s quality and overall value to the community.

Landscape architects integrate transportation goals with community values by providing expertise in comprehensive corridor planning, pedestrian scale design, historic preservation, visual/scenic/aesthetic values, and community involvement.  Landscape architects assist in facilitating timely project delivery and building community consensus by implementing the principles of CSS.

Mandella Parkway

Mandela Parkway in Oakland balances transportation goals with community values
and results in a safe and attractive pedestrian-friendly streetscape.


Landscape Architecture recognizes the effects that transportation facilities have on local communities and encourages the integration of these facilities into their context to reflect the aesthetic, environmental, scenic, and cultural values of the affected community.  For example, landscape architects collaborate with local communities through Caltrans’ Community Identification, Gateway Monuments, and Transportation Art programs to enhance existing transportation facilities to meet the goals and expectations of both the local community and the public-at-large.

Community identification is images or text that conveys information about a region and provides visual representation of a community’s identity, including its history, resources or other defining characteristics.  Landscape architects assist local communities in the development of their community identification proposals for placement on required engineering features such as sound walls, retaining walls, bridges, and slope paving. 

Caltrans Community Identification

Community identification painted upon an existing
overcrossing on Route 183 in Monterey County.


Gateway monuments are freestanding signs that are not integral or otherwise required for the highway facility that communicate the name of a city, county or township and can include imagery that reflects a community’s identity.  Landscape architects assist local communities in the development of their gateway monument proposals and facilitate their approval.  

Caltrans Gateway Monument

A gateway monument located off Route 80 announces the
entry into the City of Rocklin in Placer County.


Transportation art provides a means by which local communities and artists can enhance existing transportation facilities to reflect a community’s values, culture, and characteristics.  Transportation art may include graphic or sculptural artwork, either freestanding or placed on required engineering features such as sound walls, retaining walls, or bridges.  Landscape architects provide guidance to local communities for their transportation art proposals and shepherd them through the approval process.

Transportation Art

A transportation art mosaic on Route 41 in Fresno depicts the character of a local scenic landscape.


For more information about community identification, gateway monuments, and transportation art see:

PDPM – Chapter 29, Section 6, Transportation Art, Section 8 Community Identification, and Section 9 Gateway Monuments.

Encroachment Permits Manual - Sections 501.3F and 501.5.


Multimodal Mobility

The Caltrans mission to improve mobility across California is not only about facilitating efficient travel in cars, but about moving all people safely, regardless of their mode of transportation.

Accommodating multimodal transportation is a major component of Complete Streets which strives to integrate all users safely into the transportation system.  Caltrans Deputy Directive 64R1 - Complete Streets: Integrating the Transportation System indicates Caltrans’ commitment to balancing the needs of motorists, transit riders, pedestrians, and bicyclists within the highway system.  As a member of the Project Development Team (PDT), the landscape architect’s unique expertise in human-scale design helps ensure that transportation projects meet the goals of this policy. 


Bicyclists’ mobility is improved through sharing the highway facility with motorists.


The landscape architect’s role in multimodal mobility is to provide expertise on non-motorized traveler design criteria and be involved early and continuously on the PDT to address the needs and safety of non-motorized travelers on the State highway system.  Landscape architects are specialized in the area of human-scale design which makes them vital on the PDT to address safe and convenient integration of all users into the highway facility.  Landscape architects understand that providing access for all modes of transportation will increase roadway capacity, relieve congestion, protect the environment, improve health, and improve quality of life. 

Calistoga Main Streets

State Route 29 in Calistoga is the main street of the community and provides
multimodal access and a visually pleasing environment for all who visit the downtown area.


When multiple modes of transportation share the same facilities, the safety of all users must be addressed through design.  Landscape architects work with the PDT to improve safety by developing design solutions that influence driver behavior to improve the conditions for non-motorized street users, including reducing traffic speeds and improving the visibility of pedestrians and bicyclists.  These “traffic calming” measures can also enhance a community’s livability.  They include:

  • Raised landscaped median islands
  • Medians that provide refuge areas for pedestrians crossing the street
  • Pavement treatments such as colored or textured crosswalks and intersections
  • Street trees and landscaped buffer strips that separate pedestrians from cars and bicycles
  • Roundabout intersections
  • Separate bike lanes
  • Lower speed limits
  • Reducing the number of lanes
  • Reducing lane widths
  • Synchronized traffic signals
  • On-street parking
  • Bulbouts (curb extensions)
  • Rumble strips


Roundabouts are a traffic calming measure that provides numerous safety advantages over
conventional intersections and can enhance livability by improving pedestrian mobility, aesthetics,
and air quality.  This roundabout is located at the Route 101 ramps in Milpitas.


For more information on traffic calming measures see the Caltrans publication Main Streets: Flexibility in Planning, Design and Operations.

A multimodal transportation facility provides access for people with disabilities.  Caltrans is mandated to comply with the Americans with Disabilities Act (ADA) and Section 4450 of the California Government Code which pertain to accessibility requirements.  ADA compliance is required for all transportation projects and landscape architects document and address accessibility needs early in the project development process and ensure that solutions are incorporated into the final project design.

For more information on ADA compliance see the Caltrans Accessibility Design website.

Resources available to landscape architects that provide information on multimodal mobility include:

HDM, Topic 105.3, Pedestrian Facilities and Chapter 1000, Bikeway Planning and Design.

PDPM, Chapter 31, Non-motorized Transportation Facilities.

The Caltrans Bicycle Program website.

Caltrans Complete Streets webpage.

Design Information Bulletin 82 - Pedestrian Accessibility Guidelines for Highway Projects.

FHWA website for bikes and pedestrians.

FHWA website for traffic calming.


Scenic, Aesthetic, and Environmental Resources

A primary function of Landscape Architecture is to provide design expertise to protect and preserve California’s scenic, aesthetic, and environmental resources.  Landscape architects help protect the scenic quality of the highway corridor by performing Visual Impact Assessments (VIAs) as part of the environmental process for all transportation projects.  Departmental policy requires that VIAs be performed by licensed landscape architects whether for internally or externally developed projects. 

The VIA is a technical study required by NEPA and CEQA to assess potential impacts to the visual environment that can accompany highway improvements.  VIAs document the existing visual quality of the surrounding environment, include photo simulations and other visualization exhibits that illustrate the proposed project alternatives, evaluate the expected visual change caused by a project, assess public reaction to the expected change, identify visual impacts, and recommend measures to avoid, minimize or mitigate adverse visual impacts.

Visual Impact

Landscape architects minimize visual impacts to California’s cultural and scenic resources.
This cultural landscape is on Route 1 in Sonoma County.


Aesthetics are considered in the planning and design process of all transportation projects to address visual quality, respond to community goals, and integrate transportation facilities into their context.  Landscape architects are the departmental lead responsible for highway corridor aesthetics and are consulted early in the planning and design process to provide aesthetic reviews, aesthetic design expertise, and corridor master planning.

Preserving Rock Outcroppings

Preserving and exposing rock outcroppings contributes to
the aesthetics of Route 2 in Los Angeles County.


Many design approaches are used by landscape architects to address aesthetics, including, but not limited to:

  • Locate highway alignments to be integrated into the surrounding topography.
  • Preserve existing features such as vegetation, natural slopes, rock outcroppings, scenic views, historic and cultural resources, and sensitive environmental areas to the maximum extent feasible.
  • Selectively thin or remove existing vegetation to open up scenic views.
  • Replace highway planting and natural vegetation that is removed by construction activities.
  • Grade embankment and excavation slopes to blend with natural contours and plant them to blend with the surrounding vegetation.
  • Locate and design structures to give the most pleasing appearance and blend with the setting.
  • Specify construction materials that reflect the local character.
  • Incorporate design features that respond to community, cultural, scenic, and environmental values.


The consideration of aesthetics and the environment during planning and
design resulted in the preservation of heritage oak trees on Route 680 in
Contra Costa County.


Landscape architects protect and preserve the state’s environmental resources by preserving and restoring natural ecosystems and endangered species, preventing soil erosion and stormwater pollution by providing erosion control and biofiltration, and conserving water by planting drought tolerant plants and irrigating with recycled water when available.

Landscape architects also provide design expertise in the replacement of existing native or non-native vegetation that is removed by roadway construction activities. This includes mitigation planting, revegetation, and replacement highway planting. This work helps to mitigate the environmental impact caused by highway construction projects.

I-80 alignment near Soda Springs

An old I-80 alignment near Soda Springs was graded and planted to treat stormwater,
create wetland habitat, and provide a visual transition into the surrounding forest.


To learn more about aesthetic considerations for transportation facilities see:

HDM, Topic 109, Scenic Values in Planning and Design.

PDPM – Chapter 29, Section 5, Aesthetics.

To learn more about Visual Impact Assessments see:

SER – Environmental Handbook Volume 1, Chapter 27, Visual & Aesthetics Review.

PDPM – Chapter 29, Section 2, Article 1, Definitions, General Policy, and Programs.


Highway Planting

Highway planting is vegetation placed for aesthetic, safety, environmental mitigation, stormwater pollution prevention, or erosion control purposes, and includes necessary irrigation systems, inert materials, mulches, and design features that improve the safety of motorists and maintenance workers.  In addition, highway planting provides headlight glare reduction, windbreaks, and graffiti reduction.

The landscape architect’s goal is to integrate the highway into its natural or built surroundings to maintain an area’s contextual integrity.  Highway planting design strives to achieve a balance between safety, aesthetics, maintainability, cost effectiveness, resource conservation and community values.  

Highway Planting on Highway 680

Highway planting on Route 680 in Pleasanton enhances the aesthetics along
the corridor and integrates the highway into the community.


The highway environment is often dominated by large areas of pavement, massive structures, retaining walls and noise barriers.  Landscape architects use simple planting design concepts that incorporate large scale, massed plantings that reduce the visual prominence of these elements, provide human scale to the environment, and reduce driver distraction. 

Simple, large scale planting designs are most appropriate for highway traffic speeds.  A motorist traveling along a highway corridor will typically view adjacent landscaping for only a short duration so large scale, uncomplicated plant masses are more easily comprehended and less distracting than planting designs that are small scale and intricate, making the highway environment safer for all users.

Small scale planting design is discouraged because it can be maintenance intensive and lead to an increase in maintenance worker exposure to traffic.  Also, due to limited resources, maintenance intensive landscaping cannot be maintained to the level that will satisfy stakeholder expectations. 

To read more about highway planting and irrigation go to Topics 902.3 and 902.4 in Chapter 900 of the HDM.

Simple planitng design is considered good design.

Simple planting design is considered good design in the highway
environment as demonstrated on Route 5 in Elk Grove.


Controlling erosion and keeping stormwater clean is a primary function of highway planting. Landscape architects work with the Project Development Team (PDT) to develop strategies to implement permanent and temporary erosion control treatments into all construction projects.  

Permanent erosion control techniques remain in place after completion of construction and are used to provide long-term soil stabilization for disturbed areas caused by grading operations, slope failure repairs, stream bank rehabilitation, or wildfires and function to improve stormwater quality in compliance with the National Pollutant Discharge Elimination System (NPDES) permit.  Permanent erosion control treatments, include, but are not limited to:

  • Compost incorporated into the topsoil to improve infiltration, increase water holding capacity, improve soil health, and increase rooting depth for plants.
  • Collecting duff and re-spreading it following grading activities to add microbes, organic matter, nutrients and water storage capacity to the soil.
  • Stepped slopes to reduce slope steepness, reduce stormwater runoff volume and velocity, increase infiltration, trap sediment, and create a niche for seed retention and plant establishment.
  • Mulch or compost blankets to reduce raindrop erosion, improve infiltration, conserve soil moisture, provide nutrients, reduce runoff and the transport of sediment, reduce competition from invasive annual weed species and improve the potential for vigorous long term vegetation coverage.
  • Biofiltration strips and swales to filter pollutants from stormwater and reduce runoff.
  • Planting trees, shrubs, and ground covers or brush layering to reduce raindrop erosion and hold soil in place.
  • Seeding with deep-rooting California native grasses, wild flowers and perennials to reduce raindrop erosion and hold soil in place.
  • Fiber rolls and compost socks to shorten slope length, intercept runoff and reduce its velocity, and remove sediment.
  • Rolled erosion control products such as jute mesh, netting, blankets, and turf reinforcement mats to provide immediate protection from surface erosion and help retain soil moisture, improving seed germination and vegetation establishment.

Temporary erosion control treatments are those that are short-lived or removed prior to the completion of construction and include, but are not limited to:

  • Drainage inlet protection that prevents sediment from entering storm drain systems.
  • Check dams located at areas of concentrated flow to reduce stormwater runoff volume and velocity and remove sediment.
  • Silt fences to remove sediment from stormwater runoff.

For more information on erosion control visit the Erosion Control Toolbox on the LAP website.

Photograph of stepped slopes.

Stepped slopes combined with brush layering is a permanent treatment that
helps reduce stormwater runoff, improve infiltration, and prevent erosion.


Highway planting must be buildable, durable, and maintainable, considering life cycle costs and maintenance resource limitations.  Landscape architects solicit input from maintenance staff starting early in the design process.  Maintenance intensive activities are minimized or eliminated by the highway planting design whenever possible.  To achieve a roadside that is maintainable highway planting designs include:

  • Drought tolerant, low maintenance plant materials appropriate to the location.
  • Irrigation systems that are durable and easy to operate.
  • Mulches to discourage weed growth, reduce herbicide spraying, and conserve soil moisture.
  • Plant establishment periods that deliver established plants to Maintenance.
  • Paving of narrow, high risk areas.
  • Features to reduce maintenance worker exposure to traffic.

Highway planting must be cost effective.  Landscape architects design roadsides that have a low life-cycle cost and endure for the long-term.  For example, small container-sized trees are typically chosen over larger and more expensive boxed trees.  The smaller sized tree is inexpensive, easier to plant, requires less water and fertilizer to become established, is proven to succeed in harsh highway conditions, and after a few years the growth will be comparable to or surpass that of the larger size.  Landscape architects also achieve cost effectiveness by using materials that are commercial quality, matched to project site conditions, and locally available. 

Low maintenance cost effective landscape in the City of Industry

A newly installed landscape at the 10/605 Separation in City of Industry is low
maintenance, cost effective, and will mature into an attractive highway feature.


Caltrans is a good steward of California’s limited water resources and actively manages, promotes and implements water conservation practices within the highway transportation system and associated facilities.  Cost effective and appropriate water conservation strategies are employed in the design, construction, operation and maintenance of transportation facilities including water conserving irrigation systems for highway planting and to the maximum extent practicable, the use of recycled water.

Landscape architects serve as water managers to track water usage, identify and respond quickly to irrigation system problems, and develop irrigation schedules that conserve water.  Other practices that landscape architects employ on highway planting projects to conserve the state’s limited water resources include:

  • Select drought tolerant and regionally appropriate plants.
  • Incorporate native plant species whenever appropriate.
  • Preserve established vegetation to the maximum extent possible.
  • Incorporate compost into the soil to reduce runoff and hold water in the root zone.
  • Spread wood mulch to conserve soil moisture.
  • Incorporate hardscape surfaces and inert ground covers in lieu of plants where appropriate.

For more information on water conservation visit the LAP website.

Drought tolerant plants and inert materials.

Drought tolerant plants and inert ground covers
conserve water on Route 10 in Fontana.


Roadside Management

Effective management of the roadside improves worker safety and reduces ongoing maintenance efforts and cost.  Landscape architects plan the placement of roadside features to eliminate or reduce the need for recurring maintenance activities such as vegetation control, herbicide application, pruning, mowing, and graffiti removal to reduce a maintenance worker’s exposure to traffic.

Proper location of irrigation equipment to reduce exposure to traffic

On Route 105 in Inglewood, a maintenance worker’s exposure to traffic is reduced
because this irrigation equipment is located near a gate in the right of way fence and is accessed
from a local street rather than from the highway above.


Roadside management practices include but are not limited to:

  • Place facilities that require recurring maintenance such as traffic control boxes, backflow preventers, or stormwater treatment devices at safe locations outside the clear recovery zone.
  • Provide safe maintenance worker access such as gates in the right of way fence, access roads, or maintenance vehicle pullouts to facilities that require recurring maintenance.
  • Incorporate vegetation control treatments such as paving or fiber mats under guard rails.
  • Pave narrow strips in front of concrete barriers or noise barriers to eliminate the need for weed abatement and facilitate automated litter removal.
  • Eliminate the need for pruning by placing plants where they will not encroach upon sight distances or shoulders.
  • Design noise barriers with a textured aesthetic treatment or plant them with vines to discourage graffiti.
  • Place a contrasting surface treatment such as colored and textured concrete in the area beyond the gore instead of installing planting and irrigation systems.

Roadside facilities are placed where workers can access them without being exposed totraffic.

Roadside facilities are placed where workers can
access them without being exposed to traffic.


Roadside management also considers the full life-cycle cost of transportation improvements including the long-term cost of maintenance.  The design alternatives with the lowest initial construction cost may not be the best solution if the approach will include high recurring maintenance costs.

To learn more about Roadside Management go to the HDM, Topic 706, Roadside Treatment and the Roadside Toolbox on the LAP website.

For more information about Roadside Safety see:

HDM, Topic 902 Highway Planting Standards and Guidelines.

PDPM, Chapter 29, Section 1, under the topic Traveler and Worker Safety and Section 3, Safety Roadside Rest Areas.


Roadside Facilities

Safety roadside rest areas (SRRAs) are critical safety components of the highway system with the primary purpose of reducing drowsy driving.  They provide roadside areas where travelers can safely stop, rest, and manage their travel needs.  SRRAs are unique pedestrian environments where travelers, many of whom are unfamiliar with the local area, get out of their vehicles and experience the local environment up close.  SRRAs offer the opportunity to provide these travelers with a lasting impression of California’s diverse locales, each with its own unique cultural and aesthetic qualities.

The Bowers Safety Roadside Rest Area on Route 101 in Marin County.

The Bowers Safety Roadside Rest Area on Route 101 in Marin County at
the north end of the iconic Golden Gate Bridge is home to The Lone
Sailor Memorial.


SRRAs balance the preservation and enhancement of scenic, aesthetic, environmental, and cultural features with the safety, maintainability and operations of the facility.  Landscape architects collaborate with architects, engineers, and others to design new SRRAs and rehabilitate existing facilities.  The landscape architect is responsible for site selection, developing a context appropriate architectural theme, site planning and design, and the overall coordination of project development activities on SRRA improvement projects.  

C.H. Warlow Safety Roadside Rest Area

The architectural vocabulary of the C. H. Warlow Safety Roadside Rest Area on
Route 99 in Tulare County reflects the surrounding agricultural context.


Caltrans also maintains an inventory of approximately 135 vista points throughout the state highway system.  Vista points are safe places beyond the highway shoulder where travelers can stop and observe views of outstanding scenic quality.  Landscape architects perform the site planning and design of these roadside facilities.

Richmond-San Rafael Bridge Vista Point on Route 580.

The Richmond-San Rafael Bridge Vista Point on Route 580 provides an
attractive and relaxing space to experience the views of San Rafael Bay
with San Pablo Bay in the distance.


For more information about SRRAs and Vista Points see:

Caltrans Landscape Architecture Safety Roadside Rest Area website

HDM, Topic 903, Safety Roadside Rest Area Standards and Guidelines. 

PDPM, Chapter 29, Section 3, Safety Roadside Rest Areas.

HDM, Topic 904, Vista Point Standards and Guidelines