U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
* The FHWA Policy does not prescribe a specific format for the reports supporting a request for Interstate System access. This sample outline provides a comprehensive framework that could be used for developing an Interstate access request. This sample is for illustrative purposes only. The format and content of reports supporting Interstate access requests should be commensurate with the project scope. Alternative formats and variations in report content may be appropriate. The state DOT, based on agreement with the FHWA Division Office, should ensure that all Interstate access requests contain sufficient information to allow an independent evaluation of the proposed action, with thorough consideration of all pertinent factors and alternatives. The extent and format of the documentation should be jointly agreed upon by the state DOT and the FHWA Division Office to accommodate the review and approval operations of both agencies. The documentation should be consistent with the complexity of the proposal. For example, information needs in support of isolated rural interchanges may not be as extensive as for complex interchanges in urban areas.
A summary section should be provided at the beginning of the report that clearly and concisely expresses the proposed action. A brief description of the project location and the intended action should be provided along with the purpose and need for the action (i.e. project). A summary of the project goals and objectives should be stated. The summary should address the problems or deficiencies which the project is looking to address or overcome. If a preferred alternative is known, the summary should include a concise description of the recommended improvement or action for which the FHWA concurrence in engineering and operational acceptability is being sought.
An introduction to the project should be provided that summarizes the following:
Project Description (location and proposed actions) and Background – Identify the subject interchange location and describe the surrounding area (i.e. area of potential influence). Include maps and/or aerial photography of the general project area and area of influence. Maps, aerial photos, or conceptual schematic drawings should be to an appropriate scale and show approximate distances between interchanges, major intersections, and other key features. The subject interchange location should be identified by milepost and by relation to adjacent interchanges and major roads in the system. Factors used to define the area of influence should be discussed, including interchange spacing, signal locations, anticipated traffic impacts, anticipated land use changes or other proposed transportation improvements. The report should identify whether the proposed interchange is located within a Transportation Management Area (TMA).
This section should also discuss the project history and relationship to other related projects planned, pending, under construction, or recently completed. A summary describing consistency with the local planning process should also be included. Identify and reference any supporting companion studies or reports to support the project.
Purpose and Need - The specific purpose and need for the proposed action should be described. Describe what problem or deficiency the project is looking to address or overcome. The following are some possible needs and purposes to justify changes in access to the Interstate System:
This section should also identify the specific and measurable performance goals and objectives for the project and define the performance criteria used to evaluate the effectiveness of the project alternatives to satisfy the stated purpose and objectives.
Concepts Consistency with FHWA Policy – The FHWA Policy identifies eight "Considerations and Requirements" that an Interstate access request must satisfy and document for obtaining FHWA approval. The supporting report should include a section describing how the proposed action is consistent with each of the eight required policy points. This is a very important component of the documentation since appropriately satisfying the eight points is the basis for approving the recommended change in access. There are many possible formats for addressing the eight policy points. Some agencies chose to format the entire report around the eight points by making a separate chapter for each point. Regardless of the report format used, a thorough description of how the proposed action satisfies each point individually must be provided in some fashion. For convenience and clarification, the eight policy points are paraphrased and summarized below:
The access needs cannot be adequately satisfied by existing interchanges and/or local roads and streets in the corridor can neither provide the desired access nor can they be reasonably improved to satisfactorily accommodate the design year traffic demands
Intent: It must be demonstrated that the existing interchanges and/or the local network in the area can neither provide the necessary traffic service nor be improved to satisfactorily accommodate the design-year traffic demands. Reasonable improvements to the existing network must be considered, including improved access management along the crossroads, improved traffic control strategies, modifying ramp terminals and intersections, and adding turn lanes or lengthening turn lane storage.
All reasonable alternatives for design options, location and TSM improvements have been considered
Intent: All reasonable alternatives for interchange design configuration options, new interchange location choices, and transportation system management type improvements (such as ramp metering, mass transit, and High Occupancy Vehicle facilities) have been assessed and provided for if currently justified, or provisions are included for accommodating such facilities if a future need is identified. A thorough description of the alternatives considered should be presented in a subsequent chapter of the report, however, a summarizing statement to affirm that all reasonable alternatives were considered is appropriate in this section.
Proposal does not have a significant adverse impact on safety and operations
Intent: The proposed action does not have a significant adverse impact on the safety and operation of the system (including the freeway mainline lanes, the existing new or modified ramps, the intersections of the ramps and the crossroads, and the local street network) based on an analysis of current and future conditions. The analysis shall include at least the first adjacent existing or proposed interchange on either side of the proposed change in access. The crossroads and the local street network shall be analyzed to the extent necessary to fully evaluate the safety and operational impacts that the proposal may have (at least to the first major intersection on either side of the proposed change in access). Requests for a proposed change in Interstate access must include a quantitative and qualitative assessment and summarizing description of the expected safety and operational impacts. The assessment should confirm that the existing and/or improved local street network is able to safely and efficiently accommodate and distribute the traffic resulting from the proposed change in access. Providing designs that are intuitive to the unfamiliar driver is a key element of the likely safety performance of the proposal. Therefore, as a part of the access request, a conceptual plan of the type and location of the signs proposed to support the design alternatives must be provided. (The conceptual signing plan may be included as an Appendix, but the discussion regarding policy point #3 should address the issue of signing the proposal for ease of driver understanding.)
An interchange that connects to a public road, meets or exceeds design standards, and provides for all traffic movements is provided
Intent: The report should verify that the proposed access change connects to a road that is owned and operated by a public entity. The proposal should provide for access that safely and efficiently accommodates all traffic movements on the Interstate and along the primary intersecting crossroad. Partial interchanges may be considered on a case-by-case basis if unusual circumstances exist. The proposed access improvement project should meet or exceed current standards for the Interstate highway system. Any anticipated design exceptions should be discussed in the access proposal.
The proposal is consistent with local and regional land use and transportation plans
Intent: The documentation must affirm that the proposal considers and is consistent with local and regional land use and transportation plans. Prior to receiving final approval, all requests for new or revised Interstate access must be included in an adopted Metropolitan Transportation Plan, Statewide or Metropolitan Transportation Improvement Program (STIP or TIP), and the Congestion Management Process within transportation management areas as appropriate, and as specified in 23 CFR part 450, and the transportation conformity requirements of 40 CFR parts 51 and 93.
Consistency with corridor and comprehensive network studies and master plans
Intent: The request for a new or revised interchange must demonstrate coordination with appropriate master plans and/or comprehensive transportation network system improvement studies. In corridors where the potential exists for future multiple interchange additions, a comprehensive corridor or network study must accompany all requests for new or revised access with recommendations that address all of the proposed and desired access changes within the context of a longer-range system or network plan.
Coordination with the area's development and other transportation system improvements
Intent: Requests generated by new or expanded development requires appropriate coordination between the development and related or otherwise required transportation system improvements. The report must demonstrate that appropriate coordination has occurred between the development and any proposed transportation system improvements. The request must describe the commitments agreed upon to assure adequate collection and dispersion of the traffic resulting from the development with the adjoining local street network and Interstate access point.
Consideration and coordination with environmental process
Intent: To assure coordination of the access request with the NEPA process. The report should affirm that the proposal is, or is expected to be, included as an alternative in the required environmental evaluation, review and processing. The access request report should describe the current status of the environmental processing and any known environmental issues or information that could be substantial to the decision-making process.
This section should identify the conditions existing in the project's base year. Text, figures and tables should be used to provide relevant information to describe the existing transportation system, travel demand, performance (operations and safety), land use and environmental conditions considering the following:
Existing Facility and Transportation Network – Important characteristics of the Interstate route and other major facilities within the project area of influence should be stated. Information including functional classifications, number of primary lanes, level of access control (e.g., limited - or controlled-access), and current ADT should be provided in text, table or graphic format for major facilities within the study area. This section should describe the existing configuration, geometry and other design features of existing interchanges and their cross roads in the area of influence, including identifying any elements that do not meet current design standards. This section should summarize existing conditions based upon field reviews and site visits during peak and off-peak periods. Information on geometric conditions should include: number of lanes, lane widths, shoulder widths, acceleration lane lengths, deceleration lengths, weave section lengths, grades and available sight distances at key locations. This section should also identify any other interchanges being developed within the area of influence and discuss their status and relation to the proposed change in access. This section should also summarize the existing safety performance and operating conditions (quality of service) of the facility and network. This section should summarize existing operational conditions (daily volumes, peak hour volumes, LOS, delay, queue lengths or other criteria) of the system within the area of influence. Existing transit operations within the area of influence should also be summarized along descriptions of the transportation network for pedestrians and bicyclists.
Existing Land Use and Demographics - Existing land use within the project area should be summarized by general land use classifications (residential, commercial, industrial, institutional, recreational, etc.). Major developments within the study area should be identified. This section should also identify significant population and employment statistics and trends within the project area. If appropriate, include a summary of traffic analysis zones for the base year from the selected travel demand forecasting model.
Environmental Constraints - This section should identify any known major environmental issues or areas of concern that will be addressed in subsequent project studies. This analysis is not intended to provide extensive examination of environmental and community impact issues that will be accomplished in the NEPA process, but should describe any known controversies or issues of community concern associated with this or related projects.
This section should summarize the methodology for performing the analyses used in developing the Interstate access request. The discussion should provide sufficient detail for the reader to understand the tools and processes used and summarize the assumptions made in the analyses. Examples of what should be included here are descriptions of the basis for selecting the project influence area and the analysis years. Also, this section should describe the basis used for deriving the future year traffic forecasts, any deviations or refinements from established planning models, sources of the traffic volumes used, assumed growth rates, assumed peak hour factors, truck percentages, K-factors, and other assumptions used in the analyses.
This section should include a narrative on the development of the future year design traffic used for evaluating the alternatives. Information to be contained should include network and project validation, future travel demand projections and the design traffic projections.
Area of Influence
The Interstate access request should identify an area of influence based on safety and operations concerns. The area of influence for safety and operational considerations should be based on appropriate boundaries for examining the potential impacts of the proposed action, upstream and downstream of the new or modified access. At a minimum the area of influence should extend to the adjacent interchanges and along the crossroad extending onehalf mile from the ramp terminal, or at least to the first adjacent signal in either direction along arterial roadways, or to the first major intersection.
Provide a summary of the methodology or methodologies used for conducting the operational analyses. As a minimum, the operational analyses should be conducted based on procedures specified in the current edition of the Highway Capacity Manual (HCM). Computations are commonly performed using the Highway Capacity Software (HCS+) and Synchro software. Computations should be performed on mainline freeway segments, the ramp merge/diverge locations, ramp terminal intersections and other significant intersections within the project area of influence. Traffic simulation models such as CORSIM may be extremely useful to supplement the HCS analyses. This section should discuss the use of the traffic analysis tools utilized and the calibration process used for any analyses with simulation models. Traffic analysis models should be applied using the methodology outlined in the FHWA's "Traffic Analysis Toolbox".
Provide a summary of the methodology or methodologies used for conducting the safety analysis. A review of historical crash data is suggested to identify if any patterns exist of an overrepresentation of crash frequency, crash types, or crash severity. The safety analysis methods described in the latest edition of the AASHTO Highway Safety Manual (HSM) are suggested for application on Interstate access projects. The HSM methodology includes comparison of past safety performance to statistical estimates using available Safety Performance Functions (SPFs)
This section should thoroughly discuss the alternatives considered. A narrative regarding the location and design elements should be provided for each alternative.
The No-Build Alternative provides for a baseline comparison and describes the expected future operating conditions for the transportation network. The No-Build network should include the existing transportation network plus any funded or programmed improvements that are scheduled to be open to traffic in the analysis year. Level-of-Service analyses for the No-Build Network should be performed and used as a baseline for comparison.
Reasonable improvements to the No-Build network (beyond any funded or programmed improvements that were included in the No-Build Network) should be assessed. Transportation Systems Management Alternatives Lower cost TSM type strategies must be considered.
The proposed modifications and engineering factors including structures, landscaping, schedule, cost and traffic control devices should be discussed for each alternative considered.
Issues for consideration in alternatives development
- System improvements needed
to support the interchange operations
- Consequences of phased construction of an ultimate improvement
- Select a design LOS and design criteria consistent with project context
- Construction feasibility (constructability and maintenance of traffic)
This section should describe the alternatives that have been considered and discuss the analysis of alternatives based on the evaluation criteria as well as how the alternatives satisfy the purpose and need, the applicable engineering policies and standards, traffic operations, and environmental impacts. The alternatives may then be evaluated in economic cost and benefits terms. A summary of the analysis that was performed, the methods and tools utilized, the assumptions, and the conclusions is recommended. The evaluation of alternatives should be made using measures of effectiveness that allow comparisons to the conditions anticipated to occur in the analysis years under the No-Build Alternative.
This analysis would normally consider, at a minimum, the following:
Safety – A safety assessment, including the potential safety benefits should be discussed if the proposed improvements will contribute to a reduced number or severity of crashes. This section should also discuss the project's relationship regarding public safety issues such as emergency service and evacuations if appropriate. The assessment should include:
- Nominal safety assessment
- Substantive safety assessment
Operational Performance - The quality of operational service for various network elements within the interchange area of influence (including and along the crossroads) for the existing and proposed access conditions should be presented. The operational performance should be addressed in accordance with the performance targets established for the project. These measures may include Level of Service (LOS) as defined in the Highway Capacity Manual, the project's effect on system wide vehicle-hours of travel, average travel speed, or other measures of effectiveness (MOE).
The traffic operational analysis should consider conditions in the current year, the implementation year, and design year (at least 20 years from the PS&E year). The analysis should include adjacent segments of the freeway as well as adjacent existing and proposed interchanges.
Typical components of a traffic operational analysis:
A summary of the traffic operational analysis must be presented in a form readily understandable and usable to a reviewer unfamiliar with the project.
Stakeholder and Environmental Concerns – This section should summarize stakeholder involvement or any public involvement which has occurred during the project and summarize any issues identified. A preliminary assessment of potential environmental impacts considering all NEPA elements from a fatal flaw perspective for each alternative should be presented.
Conformance with Transportation Plans - This section will discuss the proposal's relationship to Interstate Corridor Studies or similar investment studies. This section should identify the attainment status of the area for the National Ambient Air Quality Standards (NAAQS) established in the Clean Air Act Amendments. If the project is located in a non-attainment or maintenance area for ozone, the relationship of the proposed improvements to the conforming TIP, State Implementation Plan (SIP) and MPO Long-Range Transportation Plan should be discussed.
Evaluation Matrix - A matrix that summarizes the analysis of the alternatives using the key evaluation criteria is extremely useful to examine the trade-offs and potential consequences of the alternatives.
This section should identify the projected funding sources (including any private sources or toll revenues) needed to implement the improvements proposed. The project schedules should also be discussed (anticipated ROW acquisition, construction, etc.).
This section should summarize the requested change in Interstate access, identify the preferred alternative (or alternatives), summarize the results of the analysis for engineering and operational acceptability, and state recommendations for further action, such as programming the NEPA or design phases.
Appendices will be used for other supporting documents such as traffic operational analysis documentation. Preliminary design (functional design) plans showing lane configurations and proposed design features should be provided. These figures should clearly show dimensions for the acceleration and deceleration lane spacing, lane transition taper lengths, auxiliary lanes and interchange spacing (measured from the centerline of grade separation structures.) A conceptual signing and marking plan should also be provided.
Guidelines for appropriate design level of effort:
It is critical to accurately develop and reflect geometry on urban freeways and in locations where right-of-way is tight. The level of detail and effort included in the IJR should be sufficient to give assurance that the plan will not substantially change as the project moves ahead to preliminary and final design.
Other Appendix material as appropriate