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Environmental Review Toolkit


Missouri’s I-70 Tiered EIS Process

I-70 is a heavily-traveled corridor that connects the state’s two largest cities (St. Louis and Kansas City) and intersects almost every major north-south highway in Missouri. Reported to be “the first Interstate” highway in the United States, the newest sections of I-70 are now over 35 years old. In rural Missouri, I-70 carries more daily traffic than any other interstate highway.

The Missouri Department of Transportation (MoDOT) became concerned about safety as traffic continued to grow along the I-70 corridor. In January 2000, MoDOT initiated the I-70 Improvement Study to identify strategies to address the long-term needs of the corridor. The study corridor was about ten miles wide (five miles on either side of the existing I-70) and 199 miles long. MoDOT, along with the Federal Highway Administration (FHWA), decided to use tiering to conduct the planning and the National Environmental Policy Act (NEPA) activities to help expedite the study process.

Key Features

Tiering allows project sponsors to conduct the planning and NEPA activities for large transportation projects in two phases: a first tier addresses broad, overall corridor issues, such as general location, mode choice, and area-wide air quality and land use impacts, and a second tier focuses on site-specific impacts, costs, and mitigation measures. The first tier usually results in a NEPA document with the appropriate level of detail for corridor-level decisions. Second tier studies result in traditional project-level environmental documents.

Early participation in the first phase or tier allows resource agencies to provide input before broad-based decisions are made. As a result, tiering can expedite the delivery of projects with improved communication between planning and resource agencies early in the decision-making process.

Image of report cover: Interstate 70 Corridor, Draft First Tier Environmental Impact Statement

The first tier EIS was initiated with an environmental scoping session that included participation from a wide array of transportation and resource agencies. Special invitations were sent to the appropriate resource agencies along with a packet of information about the project, the first tier approach, draft purpose and need statement and a project map. A Notice of Intent announcing the scoping process for the study was published in the Federal Register in advance of the meeting.

Notice of Intent announcing the scoping process for the study was published in the Federal Register in advance of the meeting.

Those agencies invited to attend the scoping meeting are listed below.

  • Missouri Department of Natural Resources
  • Missouri Department of Conservation
  • Missouri State Emergency Management Administration
  • Federal Emergency Management Administration
  • U.S. Army Corps of Engineers
  • U.S. Fish and Wildlife Service
  • Environmental Protection Agency
  • U.S. Coast Guard
  • Federal Highway Administration

In addition to the formal scoping meeting, the interagency process has continued with periodic study team progress meetings during which resource agency personnel attended and participated.

The I-70 first tier study broadly analyzed the 200-mile I-70 corridor and was designed to produce the following products:

  • Approval of a general concept (i.e., preferred strategy) for improving I-70 by the participating agencies
  • Identification of ’Sections of Independent Utility’ for the second tier studies, including an action plan for the completion of the environmental process
  • Identification of the appropriate environmental document for each section (CE, EA, or EIS).
  • Documentation of the first tier decision that can be referenced by second tier studies to help eliminate redundancy of study activities
  • Development of agency and public consensus for the overall improvement plan

After identifying the purpose and need, seven strategies were identified to provide for safe and efficient travel along the I-70 corridor:

  1. The “No-Build” Strategy was carried forward as a point of comparison for other strategies.
  2. Transportation System and Demand Management (TSM/TDM). Manage the demand and volume of traffic on I-70 through such programs as park-and-ride lots, variable message signs and other traveler information tools and intelligent transportation systems.
  3. Widen Existing I-70. Improve existing I-70 by adding lanes and reconstructing the existing roadway to enhance safety and performance, including improved access management.
  4. New Parallel Facility. Construct a new parallel four-lane freeway or truckway close to and parallel with I-70, and improve access management at existing I-70 interchanges.
  5. New Parallel Toll Road. Construct a new four-lane toll road close to and parallel with I-70, and improve access management at existing I-70 interchanges.
  6. High-Occupancy Vehicle Lanes. Improve the performance of I-70 through special new lanes reserved for high-occupancy or multi-person vehicles.
  7. High-Speed Passenger Rail. Use high-speed passenger rail between Kansas City and St. Louis to alleviate some of the traffic pressure on I-70.

An evaluation was performed to assess the potential of each initial strategy to meet the goals of the study as defined in the purpose and need. Based on an initial screening and input from participating agencies and public comment, the initial list of strategies was narrowed to three that were found to be the most reasonable and effective: widen the existing highway, the new parallel interstate and the new parallel toll road. Each of these concepts was then evaluated by their engineering, environmental and socio-economic features to develop a recommendation of a preferred strategy.

First, preliminary design options were developed for each of the three ‘reasonable’ strategies: Design criteria (specification of vertical curves and grades, medians, lane-width, interchange capacity), improvement standards (number of lanes, capacity for future improvement, frontage roads), physical characteristics (rural vs. urban standards, relocation vs. existing alignment, interchange design, rest area improvements, weigh stations), operational characteristics, and capital costs.

Next, information and data were generated and/or obtained on the evaluation criteria for each strategy, as well as the No-Build option. Based on this evaluation, the Widen Existing Highway was selected for advancement into Tier 2. In some sections of the corridor, this strategy includes the possibility of relocated alignments.

The entire 200-mile corridor was broken into manageable sections for more detailed analysis of associated impacts and resolution of local issues. These sections are referred to as a Section of Independent Utility (SIU), which may be in place for several years before an adjacent section is completed and open to traffic. Seven individual SIUs were identified for more detailed engineering and environmental analyses. The appropriate type of environmental process (CE, EA, EIS) to be used for the second tier analysis for each SIU was proposed based on the nature of the proposed improvements and the anticipated degree of the potential impacts. For CE and EA sections, the next steps will include initiation of preliminary engineering at a greater level of detail to more specifically define any proposed interchange layouts and changes. For the EIS sections, where relocations are possible, alternatives analysis will be carried out using route location engineering.

Starting Point

MoDOT had already recognized the importance of collaborating with other agencies. In 1999, a feasibility study was completed for the I-70 corridor. Based on the results of the feasibility study, MoDOT began discussions with the resource agencies about a tiered EIS process, which MoDOT had not used before.


MoDOT and FHWA chose to use tiering to improve the decision-making process and to help expedite the implementation of the selected strategy. MoDOT was concerned that, under the traditional EIS process, delays might occur due to the length and the complexity of the study corridor. Substantial delays in later stages might have caused early upfront analysis and decisions to become outdated. Under tiering, MoDOT anticipated that decisions could be made on a corridor-wide basis with a related ROD. More detailed analysis on the SIUs that could potentially involve lengthy analysis would be done during the second tier, without impacting the first tier ROD. MoDOT anticipates that the I-70 tiering process could have been completed within four years, rather than the six to seven years that complex corridor studies typically take in Missouri. (MoDOT now anticipates that completion of the tiering process will require five years due to funding constraints.)


During the first tier, seven concepts were evaluated for their potential to meet the future transportation needs of the I-70 corridor. Each concept was evaluated for its engineering, environmental and socio-economic attributes, coordinated with the public and agency coordination program. A first tier Final Environmental Impact Statement (EIS) was completed in October 2001 following a nearly two year effort. The ROD was approved in December 2001.


Participants found that it was sometimes difficult to identify and agree upon the appropriate level of analysis for the corridor-wide decision-making.

The impacted MPOs were not adequately involved in the first tier. According to MoDOT, the affected MPOs were invited to participate in the early interagency meetings but declined as they saw the I-70 study as largely a rural project. If the project were to be done over again, MoDOT would more strongly encourage MPO participation and public involvement in the early stages.


MoDOT and FHWA expect that, since overall corridor issues have been addressed upfront, they will be able to focus their resources on project-specific impacts in the second tier. The overall Purpose and Need for a 200-mile corridor has been developed, cumulative impacts have been assessed, and there is buy-in on a single concept for improving the corridor. The hope is that first tier decisions will not need to be revisited in the second tier studies and documents.

Tier 1 Evaluation Criteria
Engineering Traffic Environmental Social and Economic
  • Capital Cost
    • New Construction
    • Right-of-Way
  • Annual O & M Cost and Preservation Cost
  • Constructability:
    • Construction Stating
    • Maintenance of Traffic
  • Implementation
  • 2030 Daily Traffic Volumes
  • Long-Term Corridor Capacity
    • Vehicle Capacity (Directional)
    • V/C Ratio Rural Areas (New/Existing)
  • Traffic Operations
  • % Corridor at Target LOS
  • Change in KC to St. Louis Travel Time
  • Travel Efficiencies (2030)
  • Change in Daily VHT
  • Change in Daily VMT
  • Service to Trucks
  • Traffic Delay During Maintenance Activities
  • Change in 2030 Accidents
  • Incident Management Impacts to Emergency Services
  • Missouri River Impacts
  • Cultural Resources Impacts
  • Hazardous Wastes Impacts
  • Parklands Impacts
  • Floodplains
  • Secondary Impacts
  • Joint Development Opportunities
  • Impacts to Existing Structures
  • Noise Impacts
  • Compatibility with Land Use
  • Impacts to Existing I-70 Business Operations
    • During Construction
    • Long-term
  • Environmental Justice
  • Cost-effectiveness
    • User Cost Savings
    • Toll Revenue
  • Benefit/Cost Ratio

By studying the collective impacts along the entire corridor in the first tier, MoDOT and FHWA lessened the risk of dividing potentially impacted environmental resources. This helps to prevent one project subsection from impacting another part of the same resource in an adjacent subsection. In addition, opportunities were created to combine mitigation efforts for project subsections. As a result, the second tier will improve and enhance the impact analyses and mitigation efforts. If second tier environmental studies occur close to project construction, the need for further studies will be lessened.

Lessons Learned

  1. Tiering is not always appropriate. Studies and projects where tiering may be most beneficial are those that can be divided into sections using logical termini for the second tier analysis, and also those where the need for improvement is quite apparent.
  2. A key to successful tiering is meaningful interagency cooperation and acceptance of the process upfront by all involved agencies. MoDOT and FHWA met with state and Federal resource agencies early to discuss tiering the I-70 project process and to foster working relationships. Involved agencies agreed upfront on the:
    • Scope and extent of information in the first tier document.
    • Extent of evaluations that would occur for each potential impact.
    • Decision making points in the process and the timing of those decisions.
    • Process for dividing the project into subsections of independent utility with logical termini for the second tier evaluations.
    By the time the first tier Final EIS was completed, state and Federal resource agencies were already familiar with the document and agreed upon the seven subsections of independent utility.
  3. Other lessons learned include the following:
    • Define expectations and obtain full commitment to the tiering process upfront with all involved agencies;
    • Explain how the tiering process works to the public, keep them informed of project decisions, and gather their input early in the process;
    • Integrate other regulatory requirements (such as Section 404 and Section 106) into the tiering process for further streamlining;
    • Conduct an overall inventory of resources in the first tier so that second tier studies can identify specific impacted resources;
    • Look beyond subsection termini to adjacent subsections in the second tier to ensure that one project does not impact another part of the same resource in an adjacent project; and
    • Ensure that first tier decisions do not restrict the consideration of alternatives for future improvements.

Next Steps

Second tier studies will provide more detailed analyses of the environmental impacts to more precisely quantify the impacts of the project. Through the second tier studies, more specific definitions and details of the improvements and their potential impacts will be developed for consideration by the general public and the various resource agencies. The second tier studies will assess and study more specifically the following items:

  • Layouts and impacts of the interchange improvements throughout the Study Corridor
  • Configuration of the highway widening in the rural areas, whether to the north or south side of the existing I-70 right-of-way, based on the guidance provided in the Final First Tier EIS.
  • Bypass alternatives within the Conceptual Corridors or improvements along existing I-70 in the Columbia Area and the Warrenton/Wright City/Wentzville Area.
  • Corridor Enhancement Plan, as conceptualized within the Final First Tier EIS, to be developed and implemented corridor-wide in conjunction with the I-70 improvements.
  • Rest area locations and further schematics of area layouts and features.
  • Location and basic configuration of all improvements will be finalized
  • All approvals and clearances will be obtained
  • Intelligent Transportation System plan for the whole corridor including further consideration of those ITS measures documented in the Final First Tier EIS

The second tier study effort, referred to as Improve I-70, was launched in the spring of 2002 and focuses on seven coordinated but independent studies in distinct geographic areas of the I-70 corridor. The location, design, environmental impacts, and costs associated with the widening and reconstruction strategy selected in the first tier will be analyzed in detail. Second tier studies are scheduled for completion by the end of 2004. MoDOT and FHWA anticipate producing two EISs, four Environmental Assessments, and one Categorical Exclusion. MoDOt has held associated public meetings throughout the process.

MoDOT has not implemented a standard set of procedures to help determine whether to use the tiering process on future studies. The decision to use the tiering process will be made on the nature and complexity of the purpose and need and study area.

Image of a map representing the Project Area. Points on map: I-470 to Odessa (1 EA); Odessa to Route 5 (2 EA); Route 5 to Rockport (3 EA); Rockport to Route 2 (4 EIS); Route 2 to Route 54 (5 CE); Route 54 to Route 99  (6 EA) Route 9 to Connection to St. Louis (7 EIS).

For further information

Kathy Harvey
I-70 Project Manager
Technical Support Engineer — Design Division
Missouri Department of Transportation
P.O. Box 270 (105 W. Capitol Avenue)
Jefferson City, MO 65102

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