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PDDG Chapter 1 - Introduction

Chapter 1 of the MassDOT Project Development and Design Guide
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1.1 Introduction

Transportation and quality of life in our Commonwealth communities are inextricably linked. This connection is largely influenced by the roles that highways, streets, pathways, and sidewalks play in our lives. Excellent transportation facilities and options are critical to a healthy and vibrant Commonwealth. The Massachusetts Department of Transportation (MassDOT) strives to develop and maintain a comprehensive and effective multimodal transportation network.

MassDOT must consider a broad range of factors that will contribute to maintaining and improving this transportation network, including:

  • Safety for all users, especially people walking, biking, and taking transit
  • Functionality and the need for access and mobility
  • Accessibility for people of all ages and abilities as a prerequisite to access to employment, education, recreation, and healthcare
  • Mutual support and compatibility between transportation facilities/services and the adjacent land uses and associated activities they serve
  • Sustainability and resilience
  • Equitable public participation and project outcomes for Environmental Justice (EJ) populations
  • Consistency with transportation plans and policies/environmental regulations that guide the community, the region, the state, and the Federal government
  • Transportation facility design and operational requirements established by other agencies that own and operate portions of the transportation system
  • Input and participation from local constituents and the appropriate local, regional, and state reviewing agencies
  • Cost effectiveness and the value that transportation investments return to the Commonwealth

The Commonwealth of Massachusetts is committed to caring for the built and natural environments by promoting sustainable development practices that minimize negative impacts on natural resources as well as historic, scenic, and other community values. While doing so, the Commonwealth also recognizes that transportation improvements have significant potential to contribute to local, regional, and statewide quality of life and economic development objectives.

Beyond Mobility, the Massachusetts 2050 Transportation Plan, is the current blueprint for guiding MassDOT’s transportation decision making and investments. Thoughtful planning results in well-designed transportation infrastructure that is responsive to its context. By bringing together transportation professionals, local community members, and interest groups, transportation planning can produce public facilities and programs that support community goals; provide safe, efficient, and resilient transportation for individuals and goods; enhance the economy; and protect the natural environment.

1.2 Purpose of the Project Development and Design Guide (PDDG)

The purpose of the Project Development and Design Guide (PDDG) is to define MassDOT’s project development process and guide the planning and design of transportation projects that address the broad range of factors listed above. The PDDG’s intended audience includes planners, designers, practitioners, and decision makers.

The previous edition of the PDDG, published in 2006, expanded MassDOT’s framework for incorporating context-sensitive design and multimodal elements into transportation improvement projects. This edition of the PDDG expands on those elements and formally incorporates process changes and guidance revisions that have occurred since 2006. MassDOT is actively updating the 2006 edition’s content and modernizing the PDDG to a web-based format to aid the ease and regularity of future updates. Updated chapters are published in this new web-based format. For chapters currently undergoing updates, the 2006 edition is temporarily posted to that chapter’s web page.

1.3 Guiding Principles of the PDDG

The following are the guiding principles for development of the PDDG.

  • Multimodal design ensures that the safety, mobility, and comfort of all a transportation system’s users (people walking, people biking, and people driving) are considered equitably through all phases of a project so that even the most vulnerable (e.g., children and the elderly) can feel and be safe within the public right-of-way. This includes a commitment to full compliance with state and Federal accessibility standards for people with disabilities.
  • Context-sensitive design is a collaborative, interdisciplinary approach that involves all constituents to develop a transportation facility that fits its physical setting and preserves scenic, aesthetic, historic, and environmental resources while maintaining safety and mobility for all users. Planning should incorporate these overarching principles of context-sensitive design throughout project planning, design, and construction.
  • A Safe System Approach exercises a proactive, holistic approach that aims to eliminate fatal and serious injuries for all users by designing and operating the transportation system in a way that accommodates human mistakes and reduces the risk and severity of consequences.
  • A clear project development process establishes a transparent development and design process that can be administered consistently throughout the state. The ideal process results in project consensus among constituents that can be expeditiously accomplished within reasonable project cost.

Multimodal Design

A guiding principle of the PDDG is that the Commonwealth’s roadway system should provide safe facilities for all public right-of-way users, including:

  • Pedestrians, including people requiring mobility aids (canes, service animals, wheelchairs, walkers, and scooters)
  • Bicyclists
  • Drivers and passengers
    • Transit vehicles
    • Trucks
    • Automobiles and motorcycles

Historically, highway design manuals have focused on guidelines that ensure safe operation of motor vehicles. The PDDG does not diminish the importance of providing a safe operating environment for motor vehicles; rather, it provides balanced guidance for public right-of-way design objectives to serve both non-motorized (i.e., people walking and biking) and motorized travel.

The PDDG considers non-motorized transportation modes as fundamental to the design process. As such, pedestrian and bicycle design requirements within a shared right-of-way are integrated throughout the design chapters. In addition, guidance and references for shared use path design are presented as a separate chapter. Design requirements associated with public transit operations are also integrated into the chapters throughout the PDDG.

MassDOT and Commonwealth policy encourages planners, designers, practitioners, and decision makers to fully plan and design for non-motorized modes of transportation throughout the planning, design, and construction phases of a transportation improvement project. Ultimately, thoughtful consideration and evaluation of all modes should result in a robust, multimodal transportation system for the Commonwealth that accommodates all users safely and efficiently within the public right-of-way.

Context-Sensitive Design

A second guiding principle of the PDDG is that roadway projects should be planned and designed in a context-sensitive manner. The PDDG has been developed to ensure that projects intended to improve the roadway network in the Commonwealth are implemented in such a way that the character of the project area, the values of the community, and the needs of all roadway users are fully considered.

An important concept in planning and design is that every project is unique. Whether the project is a modest safety improvement or a 10-mile upgrade of an arterial street, there are no generic solutions. Each project requires practitioners to address the needed roadway improvements while safely integrating the design into the surrounding natural and built environment. Several characteristics of context-sensitive projects have been identified through Federal Highway Administration (FHWA) research and workshops. Among these concepts, the following are adopted by the PDDG:

  • The project satisfies its purpose and needs as agreed to by a wide range of constituents. This agreement is forged in the earliest phase of the project and amended as warranted as the project develops.
  • The project is a safe facility for users of all ages and abilities as well as for the surrounding community.
  • The project meets or exceeds minimum design standards for accessibility for people with disabilities and gives attention to universal design principles.
  • The project is in harmony with the community and preserves environmental, scenic, aesthetic, historic, and built and natural resources of the area.
  • The project is well managed and involves efficient and effective use of the resources (time, budget, community) of all involved.
  • The project is designed and built with the least possible disruption to the community.
  • The project is seen as having added lasting value to the community.

The PDDG draws from the state-of-the-art in roadway design. Design guidelines are consistent with those described in the 2018 Edition of A Policy on the Geometric Design of Highways and Streets by the American Association of State Highway and Transportation Officials (AASHTO), also known and referred to throughout the PDDG as the “Green Book.” The PDDG also incorporates the additional guidance contained in AASHTO’s A Guide for Achieving Flexibility in Highway Design (2004), Guide for the Planning and Design of Pedestrian Facilities (2004), and Guide for the Planning and Design of Bicycle Facilities (2012) as well as the Federal Americans with Disabilities Act Standards for Accessible Design (2010) , U.S. Access Board’s Public Rights-of-Way Accessibility Guidelines (2023), and the Massachusetts Architectural Access Board’s Rules and Regulations (2006).

In addition, research conducted under the auspices of the Transportation Research Board (TRB) and other organizations was considered and incorporated into the PDDG, as appropriate. Along with the design guidance formulated specifically for the PDDG, this guide also includes practices found in manuals for other states and communities.

Safe System Approach

A third guiding principle of the PDDG is the Safe System Approach to eliminating deaths and serious-injury crashes. The concept of safe speeds is a key component of the Safe System Approach. Humans are less likely to survive high-speed crashes. When crashes do happen, they must be managed so that the kinetic energy exchange on the human body is kept below the tolerable limits for serious harm to occur. Reducing speeds can accommodate human-injury tolerances in three ways: reducing impact forces, providing additional time for drivers to stop, and improving visibility.

MassDOT’s Safe System Approach aligns with the United States Department of Transportation’s (USDOT) adoption of the Safe System Approach at the core of its National Roadway Safety Strategy. MassDOT’s Safe System Approach as it applies to roadway users, measures of effectiveness, and speed is discussed in Chapter 3, Basic Design Controls.

A Clear Project Development Process

A fourth guiding principle of the PDDG is to present a clear project development process that project proponents and constituents can easily understand. This process should allow for consistent administration throughout the Commonwealth.

Often, the process through which a project is developed is as important as the design standards employed. The project development process outlined in the PDDG defines the need for early identification of issues and alternatives, open and continuous involvement with project constituents, and a clear decision-making process. This process should ensure that community values; natural, historic, and cultural resource; and transportation needs are fully considered throughout the planning, design, and construction phases of a project.

A clear and consistent project development process is important for several reasons. The most significant are:

  • To encourage early planning and evaluation so that project needs, goals, objectives, issues, and impacts can be identified before significant resources are expended
  • To ensure context sensitivity through an open, consensus-building dialog with project constituents
  • To achieve consistent expectations and understanding between project proponents and those entities who evaluate and prioritize projects (including MassDOT’s Project Review Committee and Metropolitan Planning Organizations as described in Chapter 2)
  • To facilitate efficient allocation of resources based on pre-established project selection criteria and consistency with local, regional, and statewide priorities

An effective process helps achieve projects that respect community values and protect or enhance the natural and built environment while meeting transportation needs. The FHWA and AASHTO clearly establish the importance of a sound project development process for achieving context-sensitive highway solutions in their Flexibility in Highway Design and A Guide to Achieving Flexibility in Highway Design publications.

Objective, Coordinated, Transparent, and Inclusive Transportation Decision Making

The transportation decisions we make today will affect our Commonwealth for many years to come. While transportation improvements can generate increased mobility and allow for economic growth, they also profoundly affect the nature of our communities and our environment. For these reasons, it is vital for the Commonwealth to establish an objective and inclusive transportation planning and project-development process in which all the effects of transportation proposals can be understood and considered.

Communication about, administration of, and understanding of the process through which potential projects are evaluated can improve the efficiency of the allocation of transportation resources. If project proponents and reviewers share a continuing dialog about project issues, review procedures, and evaluation criteria, then proponents are likely to focus their energy on projects that have strong support and avoid spending scarce resources to advance projects that will ultimately be rejected.

Decisions should be made in a coordinated manner, with decision makers considering the needs of all affected citizens and ensuring that services are delivered in the most efficient and orderly way. Decisions should also be made in as transparent a way as possible, with public knowledge not only of the final decisions but of the process used to reach those decisions. And lastly, all decisions should be made in an inclusive manner, with the active participation of individuals, businesses, interest groups, and affected constituencies.

To assess transportation projects across modes in a consistent and systematic manner, transportation agencies and Metropolitan Planning Organizations (MPOs) use objective evaluation criteria at several steps of the project development process:

  • To evaluate projects early in the planning process
  • To evaluate projects at various milestones and ensure that resources are allocated to sound projects, thereby increasing effectiveness and reducing costs
  • To evaluate projects for inclusion in MPO Transportation Improvement Programs, Regional Transportation Plans, and transportation agency capital plans

Chapter 2 provides a description of the project evaluation criteria as well as guidance on how they should be integrated into the MassDOT project development process.

1.4 Use of the PDDG

The PDDG describes the project development procedures and design guidelines applicable to projects with MassDOT involvement. It is expected that this guidance will also be valuable to municipalities, authorities, and other entities involved in the design and development of highways and streets as well as other transportation facilities.

The PDDG should be followed if one or more of the three following situations exists:

  • MassDOT is the proponent
  • MassDOT is responsible for project funding (state or Federal aid projects)
  • MassDOT controls the infrastructure (projects on state highway)

This may include projects that are privately funded or projects that are funded by other state or Federal sources. If a municipality is pursuing a project on local roads with local funds, Chapter 90 allocations, block grants, or other programs, the procedures described in the PDDG remain useful but do not need to be strictly followed. Municipalities should consult with the District Highway Office for guidance to ensure compliance with the requirements of the specific funding program.

In addition to MassDOT, many other entities may be involved in a project, either as a proponent or as a constituent. The PDDG is a useful resource to a broad range of constituents, including:

  • MassDOT and other State Authorities
  • Metropolitan Planning Organizations
  • Regional Planning Agencies
  • Local elected officials, boards, and authorities
  • The general public and interest groups
  • State and Federal regulatory agencies
  • Consultants and design professionals

Before any project design work is undertaken, users of the PDDG are urged to read Chapter 2, Project Development. Chapter 2 details the progression of steps to be taken, ranging from project conceptualization through completion. Chapter 2 also discusses the importance of coordinating project elements with appropriate groups or organizations to ensure a successful process.

1.5 Structure of the PDDG

The next 17 chapters of the PDDG cover the project development process, design guidance, and plan preparation guidance as follows:

1.6 Addenda and Future Updates

Transportation planning processes and design guidance are constantly changing. As new or refined planning and design guidance or procedures are issued, MassDOT will update the applicable section of the PDDG and issue notifications to PDDG users. Each update to a PDDG chapter will be accompanied by a change log that summarizes the updates and revisions.

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