skip navigation
print icon Print

Indirect Effects/Cumulative Impacts

Case Studies

Filter by :    
select
 | 
select
 | 
select
    Reset

Listed below are examples of success stories, best practices, and/or innovative tools/approaches. This section will grow as entries are submitted or links to other sites with useful examples are provided. If you believe your agency has utilized a best practice/approach that others could learn from, please submit a short description to AASHTO (including any pertinent links) on the Share Info with AASHTO form. Please note that currently submissions are only being accepted from governmental entities.

Florida

Florida DOT Develops Standard Process to Conduct Cumulative Effects Evaluations

The Florida Department of Transportation has developed comprehensive guidance on determining the potential cumulative effects of transportation projects on sensitive resources in the state.

The Cumulative Effects Evaluation Handbook is intended to provide a standard process that is efficient, legally sound, and flexible while ensuring that potential impacts on resources are fully considered and documented in the environmental review process, according to Marjorie Bixby, manager of the Environmental Management Office at FDOT.

The handbook, published in December 2012, outlines when cumulative effects evaluations are needed and provides a 10-step process to guide practitioners. The goals of the process were to provide legally sufficient evaluations; enable project time and cost savings through an efficient, standardized approach; reduce sources of disagreement over methodologies; identify potentially controversial projects early in project development; and reduce costs by using area-wide evaluations for multiple projects.

Bixby, along with FDOT Natural & Community Resources Administrator Xavier Pagan, said that development of the handbook has provided needed consistency in a process that had often been complex, confusing, and time consuming.  The handbook was developed with input from state and federal transportation agencies, resource agencies, and other stakeholders such as planning organizations.

Under the National Environmental Policy Act, environmental impacts must be considered for federal actions – such as federally funded or permitted highway projects. Such impacts include direct, indirect, and cumulative effects of the action. Quoting regulatory definitions, the handbook says direct effects “are caused by the action and occur at the same time and place” and indirect effects “are caused by the action and are later in time or farther removed in distance, but are still reasonably foreseeable.”

“Cumulative impact is the impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (Federal or non-Federal) or person undertakes such other actions.”

While transportation agencies generally have had success analyzing direct and indirect effects for their projects, cumulative effects analyses have been more problematic – resulting in an increasing number of successful legal challenges in recent years.

The FDOT Cumulative Effects Evaluation Handbook addresses effects on resources such as the endangered Florida Panther. Photo: U.S. Fish & Wildlife Service

The handbook describes how cumulative effects evaluation differs based on the project’s class of action under NEPA – categorical exclusion, environmental assessment, or environmental impact statement. It also provides guidance on types of projects for which a cumulative effects evaluation might be appropriate. These include: new facilities or those requiring substantial right-of-way; projects with direct or indirect impacts on environmental resources, particularly resources that are declining or that have protected status; projects that increase access to areas suitable for development; and projects where other planned actions may impact resources affected by the project.

Ten-Step Process

When further analysis is needed to address concerns about cumulative effects, a cumulative effects analysis should be conducted, focused on specific resources of concern. The handbook outlines the following 10 steps:

  1. Initiate the cumulative effects evaluation: this can be done early in the process, during scoping, to help focus studies on resources of concern.
  2. Identify resources of concern: this includes elements of the natural and human environment -- focusing on resources in poor or declining conditions that may be substantially affected by the project or other activities in the area.
  3. Define the study time frame: this involves establishing and documenting the outer years of the time horizon for identifying past and future effects.
  4. Determine the potentially affected resource area (PARA): this is the geographic study area used in the evaluation and should encompass the resources affected by the project to the extent in which its alternatives contribute to the cumulative effects on the resources
  5. Evaluate past and present impacts on the resource: this includes an analysis of past and present effects, including the current condition of each resource, how it got to its current state, and major trends affecting the health of the resource – including protective regulations or conservation programs.
  6. Evaluate effects of reasonably foreseeable future actions: this includes identifying future actions that may affect the resources of concern – including all types of actions, not just transportation projects – and describing the direct and indirect effects of these actions.
  7. Add direct and indirect effects of build alternatives: this summarizes the direct and indirect effects of the project alternatives, focusing on resources of concern for the evaluation.
  8. Assess the potential for cumulative effects: this involves using information from previous steps to consider how a particular resource responds to change and to estimate the combine effects on each resource of concern. Each project alternative is evaluated separately.
  9. Identify potential mitigation measures: all relevant reasonable mitigation measures to avoid, lessen, remedy or compensate for adverse effects must be identified and discussed, even if they are outside the jurisdiction of the agency.
  10. Document results: this involves completing the cumulative effects evaluation portion of the environmental document, using the level of detail appropriate for the class of action. The evaluation should be separate from the direct and indirect effects. The cumulative effects evaluation “should explain what the effects are, how they were analyzed, why the analysis methodology(s) are reasonable, and what the results of the analysis mean.”

According to the document, “It is important that all of the identified analytical elements be included in the cumulative effects evaluation. However, the steps may be modified to meet the needs of the project. The level of assessment and documentation depends on the nature of the project, the severity of impacts, and the potential for controversy.”

While the 10-step process is aimed at the project development phase for individual projects, the guide also allows for initiating the process in area-wide planning. Following this approach, the first six steps would begin during area-wide planning without focusing on any specific project, allowing the resource-based analysis to be used on any project proposed in the area.

Developing the Process

FDOT officials noted that the process was developed starting in 2006, following release of guidance from the National Cooperative Highway Research Program and AASHTO on indirect and cumulative effects.

Previously, each FDOT evaluation was done slightly differently, on a case-by-case basis.  But Pagan said as more projects came online, the agency realized this approach was not workable. FDOT decided it needed a simpler and more consistent process. “We realized we can’t have it be case by case; we’re too big of a state, with too many projects and too many NEPA studies not to have a standard process,” he said.

A task group was assigned to develop the cumulative effects evaluation process, including representatives from 11 state and federal agencies, metropolitan planning organizations, FDOT districts and Turnpike Enterprise, legal counsel, and consultants. The process also needed to fit with FDOT’s Efficient Transportation Decision Making (ETDM) process, the state’s comprehensive approach for considering potential environmental effects during transportation planning. The process was developed over several years under former FDOT employee George Ballo and a team composed of the Central Environmental Management Office staff and consultants.

The cumulative effects evaluation process was based on research of effective practices used by state DOTs, input from stakeholders, as well as case law to help determine a sound process for such evaluations.

Lessons Learned

Pagan said having the cumulative effects evaluation process documented in a handbook is an effective way to ensure consistent application for FDOT. Since publication of the handbook, about 7 environmental impact statements have been prepared using the process, and the document has been well received by transportation practitioners and resource agencies alike, he added.

The FDOT process could be replicated by other state DOTs, he said, noting that the handbook was based in part on successful procedures developed by transportation agencies in California and Texas. Pagan and Bixby both said a key issue in developing the process was defining terms such as direct effects, indirect effects (previously known as secondary effects), and cumulative impacts. “Stakeholders needed to understand that those terms represent different things and how those things apply to transportation project delivery,” Bixby said.

Initially, FDOT had called its process the “indirect and cumulative effects process,” Pagan said.  “One of the things that became obvious was that we needed to separate them.” Some stakeholders did not realize that you cannot have a cumulative impact if there are no direct or indirect impacts, he added.

Pagan also noted that agencies conducting cumulative effects analyses should use caution in identifying resources of concern. “If you’re going to identify resources of concern early, don’t make effects determinations during planning that can tie you down or cause issues when it’s not really appropriate to do so that early,” he said. “If you’re going to do it really early, be careful how you do it.”

In addition, Bixby advised being “open and communicative with the relevant agencies and stakeholders – and keep the agency with jurisdiction over the resource informed.” Because these groups helped FDOT develop its process, the handbook encourages things like looking at long-range plans, talking to metropolitan planning organizations, and talking to counties about their development plans.“It’s important to get the right players involved,” Pagan added.

“Ultimately we see that it’s very important to have a standardized process that in itself is flexible enough to apply to all sorts of situations, depending on the nature of the project and the nature of the resources in the project area,” Bixby said. The 10-step process can be applied to a variety of situations and adjusted as needed. At the same time, it documents that FDOT has carefully conducted a thorough cumulative effects determination, she added.

For more information, link to the Cumulative Effects Evaluation Handbook and the accompanying Cumulative Effects Evaluation Quick Guide; or contact Marjorie Bixby, Manager, FDOT Central Environmental Management Office, at Marjorie.Bixby@dot.state.fl.us.

[back to top]

Montana

Montana DOT Develops Guidance for Indirect Effects Analyses

A guidance document developed for the Montana Department of Transportation (MDT) will provide needed consistency and efficient procedures for determining the indirect land use and environmental effects of transportation projects in the state.

Issued in the summer of 2013, MDT's Indirect Effects Desk Reference provides an overview of regulatory requirements related to indirect effects, a step-by-step screening process to determine what level of analysis is warranted and a framework for conducting detailed analyses, where needed.

 

View from Montana Highway 200.  (Photo: Montana DOT)

MDT developed the guidance to help agency staff and consultants determine the potential for induced growth effects from road projects, taking into account the state's unique rural setting, according to Heidy Bruner, Environmental Services Engineering Section Supervisor at MDT.  MDT plans to incorporate the guidance into its Environmental Manual this summer for use on upcoming projects, Bruner said.

The guidance will help ensure compliance with requirements for analyzing projects' potential indirect effects under the National Environmental Policy Act and Montana Environmental Policy Act.

Screening Process Developed

The screening process considers information that is readily available early in the project development process regarding the characteristics and location of the project. 

A five-part screening process provides a list of questions for staff to consider. These include:

  • whether the project is exempt, such as highway maintenance and rehabilitation on the same alignment with no increase in capacity;
  • whether the project has an economic development purpose included as part of the purpose and need;
  • whether the project will substantially improve accessibility based on indicators such as travel time to key destinations;
  • whether developable land is available in the areas served by the project;
  • and whether the project region is experiencing population and/or employment growth.

Using this initial screening process, the vast majority of MDT's projects will not require detailed analysis.

Detailed Analyses

The Desk Reference provides a framework with the following steps for conducting a detailed analysis, where needed:

  • determine study goals and methodology;
  • define study area boundaries and time horizon;
  • assess existing and future no build land use patterns;
  • assess future build condition land use conditions and indirect land use effects;
  • assess the potential for indirect impacts on sensitive resources;
  • develop potential mitigation measures; and
  • document the process and results.

For the actual indirect effects analysis, the guidance recommends a combination of "collaborative judgment," which determines the "no build" vs. "build" incremental change in land use, and "allocation models," which determine  the allocation of growth predicted through collaborative judgment to specific sub areas.  "Collaborative judgment incorporates input from other people knowledgeable of the study area (local experts) to inform conclusions about future land use conditions, whether through informal interviews or more formally through a Delphi panel. Allocation models can allow the analyst to distribute a defined amount of indirect land use change at a disaggregate level (such as allocating growth in county to individual municipalities or allocating growth in a city to census tracts or traffic analysis zones," the summary said.

 Research Informed Development of Guidance

The guidance document was based on the results of research on MDT's existing practice, including a review of environmental documents developed for projects, interviews of MDT staff, and a survey of resource agency staff.  The research also included a review of relevant case law to determine how courts have interpreted when indirect effects analyses are adequate.

Researchers determined that indirect land use effects assessments in Montana had been conducted in an "ad hoc" manner. While some environmental documents provided well-thought out explanations of the relationship between the project and potential future land development, none of the documents followed a clearly defined assessment process. 

Process Offers Needed Consistency

Bruner said the research showed that there was not a large deficiency in the agency's process for conducting indirect effects analyses. Nevertheless, the new procedures offer needed consistency and structure that has been well received.

MDT has conducted training to ensure that staff and consultants have an efficient process for meeting requirements for indirect effects analyses under NEPA and MEPA. The process will be updated going forward, as needed, and will be coordinated with future updates to the MDT Environmental Manual. Bruner said the process is flexible and could be transferable to other state DOTs, but it would need to be tailored to the unique communities of each state.

According to Leo Tidd, a member of MDT's consultant team with The Louis Berger Group, the Desk Reference incorporates concepts and best practices that could be adopted by other states. "The basics  of right-sizing the level of analysis to the project issues, documenting the rationale for decisions, avoiding inconsistencies within the environmental document (such as stating the purpose includes economic development, but then failing to analyze the environmental impact of that development) apply everywhere," Tidd said.

The process used to review the state of the practice at MDT could be applied by other states to assess how they are doing on this issue, he added. In addition, the screening process could easily be adapted for use in other states to improve NEPA document timeliness and defensibility, he said. "The questions themselves are not specific to Montana and deal with drivers of land use change that are universal," Tidd said.

For more information, including a final research report, summary report, and training presentation, link to Assessing the Extent and Determinates of Induced Growth on the MDT website at http://www.mdt.mt.gov/research/projects/planning/growth.shtml or contact Heidy Bruner at hbruner@mt.gov.

[back to top]

Texas

Texas DOT Offers Simplified Guidance to Assess Projects' Indirect and Cumulative Effects

Challenges associated with assessing the indirect and cumulative effects of transportation projects across Texas have been eased by a revised and simplified set of handbooks and guidance documents developed by the Texas Department of Transportation (TxDOT).

TxDOT faces a distinctive challenge when assessing the indirect and cumulative effects of its projects across the state: the state lacks a statewide land use management policy and manages its lands at the local level. The lack of a statewide approach to land use creates varying conditions across the state that make a strictly defined indirect and cumulative effects process unfeasible—the same project could have drastically different indirect and/or cumulative effects under contrasting land use conditions created by the various land use policies of different cities.

For example, where one city may employ strict zoning laws, other cities may frequently and broadly grant variances; an interchange project that may reasonably be assumed to have a ½-mile radius Area of Influence (AOI) in the first city may require an AOI with a radius of several miles in the second city because the second city’s less strict zoning creates the possibility of a geographically much larger AOI.

The varying land use climates across the state and extensive use of frontage roads parallel to limited access facilities create an interesting challenge for Texas: how to create guidance that balances streamlining the indirect and cumulative effect analyses with the unique conditions presented by different local approaches to land use regulations.

 
TxDOT's indirect and cumulative impacts guidance helps streamline implementation of projects such as the FM 2493 Road Widening EA Project in Smith County, Texas. Photo: Texas Department of Transportation

Developing the Guidance

The Council on Environmental Quality (CEQ)’s guidelines for National Environmental Policy Act (NEPA) implementation (40 CFR §§1500-1508) established the requirement for federal agencies to consider direct, indirect, and cumulative impacts in the NEPA process. Subsequent guidance and resources provide further direction on considering indirect and cumulative effects under NEPA (e.g., AASHTO Handbook 12, NCHRP Report 466, FHWA Interim Guidance and Q & A, and NCHRP Project 25-25, Task 43).

TxDOT developed its own cumulative impacts guidance in the early 2000s, which was met with positive feedback from around the state and other DOTs. Soon after, the agency began developing a guidance that incorporated both indirect and cumulative impacts. Following the suggestion of FHWA Texas Division, the more comprehensive guidance document pulled from a variety of sources like the NCHRP Report 466—the Transportation Research Board’s Desk Reference for Estimating the Indirect Effects of Proposed Transportation Projects—to provide TxDOT project teams with a step-by-step process. Initially implemented in 2009, minor updates to the guidance document in 2010 added keys for success and how to approach small projects through added-capacity Categorical Exclusions.

Implementing the 132-page guidance document proved both successful and challenging. The guide acts as a detailed “how-to” resource of indirect and cumulative impact analysis methods. TxDOT learned, however, that document users found its size cumbersome and struggled with the unfamiliar technical terms (e.g., notable feature, impact-causing). In response, TxDOT split the guidance into two separate guidance documents—one for indirect effects and one for cumulative effects—and simplified them by consolidating the number of steps, removing technical jargon, and splitting out easily convoluted concepts, such as growth-related effects and encroachment effects. TxDOT also added an Indirect and Cumulative Impacts Handbook to provide a high level overview of the steps to conduct a thorough and defensible analyses of indirect and/or cumulative impacts that may occur as a result of a transportation project.

Nicolle Kord, TxDOT’s indirect and cumulative impacts expert, said the agency has “attempted to structure our guidance to be more accessible to a wider audience; in particular for those new to indirect and cumulative impact analysis.” For example, she said, TxDOT “attempted to make these complex ideas easier to understand by breaking them up into their individual parts (indirect encroachment impacts, indirect induced growth impacts, and cumulative impacts) as well as by removing jargon and putting guidance in plain language.”

Key Features of the Guidance Documents

The following table illustrates several key features of TxDOT’s indirect and cumulative effects guidance documents that contribute to their efficacy.

 Lessons Learned

From its original cumulative effects guidance through its most recent guidance updates, TxDOT emphasized the following lessons that may be transferable to other state DOTs:

  • Know your state: A blanket approach to indirect and cumulative impacts analysis does not work in Texas. Though other state DOTs may have a more uniform statewide land use climate, it is critical to know your area and understand that indirect and cumulative impacts are complex and often call for a case-by-case approach. Texas uses decision trees (Induced Growth Indirect Impacts Decision Tree and Cumulative Impacts Decision Tree) to help determine which projects need indirect and cumulative impact analyses.
  • Simplify: TxDOT’s simplified approach to indirect and cumulative impact analyses made it more approachable for district environmental staff, who are project and technical experts but not necessarily versed in all aspects of NEPA.
  • Consider process improvements: By emphasizing technical reports and coordination early in the NEPA process, TxDOT was able to shorten their review cycles, save time and money, and produce stronger analysis in its documents.
  • Provide one-on-one coaching: In addition to regular conference calls (“NEPA Chats”) with districts to identify and provide guidance on various NEPA issues, TxDOT found great value in one-on-one coaching with district subject matter experts on individual projects rather than implementing agency-wide theoretical classroom training in how to apply the guidance.

For more information on TxDOT’s approach to Indirect and Cumulative Effects, contact Nicolle Kord, Environmental Specialist, Texas DOT at Nicolle.Kord@txdot.gov

[back to top]

Featured Case Study

  • Case Study Photo

    Texas DOT's indirect and cumulative impacts guidance documents help streamline implementation of projects such as FM 2493 EA Project in Smith County.

    Read Case Study >Photo: Texas DOT

View All Case Studies for this Topic >

New - items posted in the last 7 days

AASHTO (American Association of State Highway and Transportation Officials)
skip navigation