128.1 Conceptual Study Report
- The Capacity Analysis for Planning of Junctions is a tool that districts can use to consider alternative at-grade intersection types based upon peak flow volumes.
The district prepares a conceptual study report, using the necessary format, for the following types of projects:
- Relatively small projects that provide specific improvements (i.e. signalization, lighting, signing, minor geometric revisions, etc.).
- Bridge replacement projects on rural low volume roads where it is obvious the only practical new location is at the existing location or adjacent to the existing corridor.
- Projects environmentally classified as categorical exclusions (CE).
- Projects pending classification as a categorical exclusion (CE2) must have the justification approved by FHWA, which results in a CE determination, prior to preparation of the conceptual study report. A CE2 form is available. (If the CE2 is determined by FHWA to be an EA, a Location Study and Alternative Analysis is required.)
For signalization projects, the conceptual study and preliminary signal layout may be combined in one submittal. Likewise, projects that provide preventative maintenance treatments or contracted level course applications to the pavement may only require the preparation of a combined conceptual study and preliminary plans.
There may be some CE or CE2 projects for which it is advisable to prepare a location study report rather than a conceptual study report. This should be considered in the case of a highly controversial project, or one in which two or more alternatives are being considered that would have different impacts on the community, such as locating an interchange. In this case, for a CE2 project, the location study is prepared concurrently with the CE2 form to aid in FHWA determination for a CE or an EA classification.
Approximately 2 months prior to preparing a conceptual study report, the district fills out the electronic request for environmental services (RES) requesting project screening and early constraint identification. Preliminary screening may have been completed in order to obtain a CE classification from a CE2; however, it is necessary to request more detailed screening to complete the conceptual study report.
The conceptual study report describes the project purpose and identified need as well as the location and proposed improvements. The conceptual study report identifies the existing and proposed features of the project. It also explains any variations from the originally identified need.
Most generally a conceptual study report will be used to describe a simple bridge replacement project or other minor road construction project. In a few instances, a project that uses a conceptual study report format will have alternates being considered. In this case, all alternates considered should be documented in the conceptual study report in a manner similar to a location study report.
Accident data, safety enhancements, access management, how traffic will be handled during construction and the need for construction incentives are all discussed in the report. The accident data is obtained from the Transportation Management System (TMS). The calculation for the project accident rate is included. The designer carefully analyzes accident data. Any unusual circumstances are noted and recommendations for correction are proposed. Safety enhancements such as guardrail or bridge modification, access management, and the need for bicycle/pedestrian facilities are also discussed.
The conceptual study report will also discuss the disposition of the existing route. This discussion will document the anticipated disposition of all sections of the existing route in a manner similar to a location study report. A description of the available options for disposition is listed in EPG 236.14 Change in Route Status Report.
All environmental work completed prior to the conceptual study report is summarized and included in the conceptual study report. The conceptual study report then discusses any unusual features or anticipated difficulties to be encountered with the project, such as known archaeological sites, historic bridges, wetlands, Section 4(f) or Section 6(f) lands, hazardous waste sites, or other environmental issues as provided by the Design Division.
The conceptual study report will contain a current estimate of the proposed costs of the improvements for each alternative. Details on the preparation of project estimates can be found in EPG 104.7 Estimates. Current cost estimates, borrow information when required, and any other pertinent information to the project that is not covered elsewhere are also provided under the remarks section of the report.
A location sketch, plan sheet drawings, existing and proposed typical sections and other documents as necessary, are attached to show each alternative for the proposed improvement.
Following the signature of the preparer, a section is included for the recommendations or comments of the district engineer. If necessary to add more detail, the district engineer's comments may be submitted with a separate letter. Following that, signature and date lines are included to indicate the district engineer's approval of the study.
Preferred design criteria are contained in EPG articles:
- 230.1 Horizontal Alignment,
- 230.2 Vertical Alignment,
- 231 Typical Section Elements for Roadways,
- 232 Facility Selection,
- 233 At-Grade Intersections,
- 234 Interchanges,
- 236.13 Designing for Right of Way, and
- 748 Hydraulics and Drainage.
Justification for varying from these standards must be submitted on a Design Exception Information Form.
Approval and submittal of the conceptual study report is detailed in EPG 128.10.