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Environmental Review Toolkit


SEMCOG Integrates Environmental Issues in the Transportation Planning Process

July 2007

The Southeast Michigan Council of Governments (SEMCOG) updated its 2030 Regional Transportation Plan (RTP) for Southeast Michigan in March 2007. In this update, SEMCOG incorporated environmental analyses and mitigation strategies, partially in response to the planning and environmental provisions in the Safe, Accountable, Flexible, Efficient Transportation Equity Act — A Legacy for Users (SAFETEA-LU). This case study provides information on SEMCOG’s process for integrating environmental analysis in their RTP. For more information on the 2030 RTP and RTP update, see

What is SEMCOG?

The Southeast Michigan Council of Governments (SEMCOG) is the regional planning agency in Southeast Michigan. SEMCOG supports local government planning through its technical, data, and intergovernmental resources. SEMCOG’s board of directors is comprised of local elected officials from its member governments and advised by technical advisory councils that convey community input on transportation, environment, community and economic development, data analysis, and education issues. Among other functions, SEMCOG serves as the metropolitan planning organization for the region.

Integrating Environmental Issues into the Transportation Planning Process

As part of the 2030 RTP Update, SEMCOG analyzed potential impacts of planned transportation projects on environmentally sensitive resources. The agency documented the analysis in a guidelines document and included some information in its plan update.

The document, called Integrating Environmental Issues in the Transportation Planning Process: Guidelines for Road and Transit Agencies, describes the process SEMCOG used. This process includes three steps:

  1. Defining and identifying environmentally sensitive resources in the region,
  2. Analyzing the likely impacts of planned transportation projects, and
  3. Addressing possible mitigation at the system-wide level.

Data Issues

SEMCOG staff conducted data analyses using commercially available geographic information systems (GIS) software. Although staff in SEMCOG’s transportation and environmental departments were already trained in GIS, SEMCOG sought outside assistance to determine significant environmental resources and appropriate buffer sizes to analyze. SEMCOG sought this assistance from environmental experts at the Michigan Department of Transportation (MDOT), the Michigan State Historic Preservation Office, local and county agencies, the state archeologist, and the U.S. Geological Survey (USGS).

Data on environmentally sensitive resources were obtained from SEMCOG, the Michigan Center for Geographic Information Data Library, Michigan State University, Michigan Department of Environmental Quality (MDEQ), MDOT, and local organizations. Included in the datasets was information on: water resources, wetlands, groundwater resources, flood prone areas, woodlands, parks and recreation areas, historic sites, cemeteries, heritage routes, historic bridges, and non-motorized facilities. Resources were included if the following data criteria were met:

  • Data were readily available in digital format suitable for mapping using GIS software;
  • Data were available for all counties in the Southeast Michigan region; and
  • Data were reasonably up-to-date and expected to remain so in the future.

SEMCOG used GIS to map and buffer its RTP projects to represent a likely area of influence. The size of the buffer depended on the project type and the environmental resource. Project buffers were then overlaid with information about environmentally sensitive resources. These analyses were used only as screening tools to flag projects for possible areas of concern. No additional analysis of possible impacts was conducted for the RTP. However, analyses conducted and possible impacts identified during long-range planning can be evaluated in greater detail at the project level.

SEMCOG has a Data and Maps page, where it publicly shares available data, including environmentally sensitive resources. These data can be downloaded by MDOT and local agencies for further analysis during project-level planning, development, and maintenance. The goal is to help agencies access and use data they may not otherwise have the resources to obtain.

Interagency Coordination and Implementation Process

After two months of data collection and analysis, and an additional two to three months to develop guidelines for design, construction, and maintenance of projects around particular resources, SEMCOG presented the draft environmental mitigation process and draft guidelines to transportation and resource agencies, including the Federal Highway Administration, Federal Transit Administration, Environmental Protection Agency, Native American Tribal Organizations, Michigan Department of Natural Resources, MDEQ, and local agencies.

Next Steps

SEMCOG plans to expand its environmental analyses with each subsequent RTP process, increasing the number of environmental resources included in the analysis as more data become available. SEMCOG will also continue to train its members and partners, including local communities and agencies, on planning and environmental topics through SEMCOG University, which is a monthly half-day seminar on topics of interest to local and regional transportation planners.

Additional Resources

To develop its own guidelines, SEMCOG referred to existing information, including the AASHTO Environmental Stewardship Practices, Procedures, and Policies for Highway Construction and Maintenance Compendium and existing guidelines from the National Arbor Foundation and state resource agencies. SEMCOG data, guidelines, and additional resources are available at


Jennifer Evans
Transportation Coordinator
Southeast Michigan Council of Governments
535 Griswold, Suite 300
Detroit, MI 48226
313-961-4869 (FAX)

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