126.2 Purpose and Need

District and Central Office staff will work together and with others to formulate a project P&N document. The P&N is extremely important in the development of any project since it is the basis that establishes why MoDOT is proposing to spend large amounts of taxpayers' money. In other words, it justifies the need. The project P&N is the basis for the range of alternatives that will be considered, their in-depth analysis and the ultimate selection of a preferred alternative. Without a well-defined, well-established and well-justified P&N, it becomes difficult, if not impossible, to determine the range of reasonable and prudent alternatives to study. More importantly, it may be impossible to dismiss the "no-build" alternative as undesirable.

The P&N for a project is comprehensive and specific. This document completely describes the existing facility, if there is one, and all of the facility need plus local and regional needs associated with the facility. The P&N identifies the transportation problem(s), safety issues, roadway deficiencies and planned development. Other possible elements are system linkage issues, modal interrelationships, and legislative directive. Each project needs to be evaluated individually to determine which elements contribute to its P&N, which will be unique to that project. For a very simple project, the entire P&N may be existing deficiencies, as with some bridge replacement jobs. For complex projects, the P&N may be a combination of all of the above items and additional needs not listed here.

It is possible that after completing a thorough P&N evaluation, it will be determined that a P&N sufficient to justify a project does not exist at this time. In this event, the process and decisions reached are documented and brought to the attention of public officials, other agencies and/or the public, as necessary. It is for this situation that we do not begin consultant negotiations to provide for the design of an improvement before the draft P&N is endorsed by MoDOT and FHWA.

The draft P&N, reviewed by the Design Division and the FHWA, is made available at the prelocation study meeting. Input from the public and others (e.g., agencies) at the prelocation study meeting may reveal information that causes the P&N to be revised. The P&N may continue to change until the final environmental document is completed. The P&N begins with a detailed description of the project area and the existing facility type. The remainder and bulk of the document details the project need.

126.2.1 Project Description

Project History

This section includes a summary of how the project was identified in the planning process and any public involvement to date including involvement with any Regional Planning Commissions or Metropolitan Planning Organizations (MPOs). In an urban area, include a discussion of why the project was included on the current Regional Long-Range Transportation Plan. The project history highlights the relative importance of this project to the local area, the region and the state. The planning process itself might have generated a P&N for a project. As long as that was done according to Federal requirements, and as long as it is reviewed and confirmed, that planning P&N can be adopted at this stage (SAFETEA - LU Section 6002 specifically addresses these requirements).

Program Data

The most current program data is tabulated. This information is used as a comparison to the cost estimates developed for the feasible alternatives. The fact that a project has been programmed is not justification for the purpose and need. The solution that has been programmed may not address the purpose and need either. The purpose and need is defined for the study independent of the program data, and alternatives should address the purpose and need for the study, not fulfill the program.

Description of Existing Transportation Facility (ies)

The description of the existing facility (ies) should include tables detailing the condition of the roadway and any bridges and railroad crossings in the project limits.

Proposed Design Criteria

The study considers both construction year (the year in which construction begins) and design year (normally 20 years after the construction year) traffic including residual traffic remaining on the existing facility. Traffic data for existing routes near the proposed corridor, as well as all intersecting state routes, need to be analyzed. All traffic information is requested from the Transportation Planning Division as early as possible so that the traffic information is available as the study progresses. Early submittal of the request is especially important where an origin and destination (O & D) study may be necessary.

Basic design criteria (reflecting functional classification, traffic and terrain) used to evaluate the alternatives considered in the study are contained in numerous EPG locations:

• 230.1 Horizontal Alignment
• 230.2 Vertical Alignment
• 231 Typical Section Elements for Roadways
• 232 Facility Selection
• 233 At – Grade Intersections
• 234 Interchanges

The district traffic engineer is consulted for the anticipated posted speed of the proposed facility. The anticipated posted speed is used to select the design criteria discussed in location study.

It is desirable to design rural divided roadways with a 70 mph (110 km/h) posted speed. Roadway sections, which contain features that cannot satisfy these design criteria are addressed by the Design Exception Process. The majority of the roadway can still be designed to the preferred design criteria in an economical manner through use of this method. However, where a considerable percentage of the roadway's length is in the "rolling" or "mountainous" category, the roadway should use the corresponding design criteria for the terrain encountered with appropriate design exceptions.

System Linkage

A brief discussion of the link that this project plays in the Missouri Transportation Plan, including a description of the facility at each terminus, is provided. All major actions (not just transportation activities whether federal, state or local) in the vicinity of this project are discussed. This discussion includes what stage in NEPA review these projects are.

If there is a gap between improvements so that logical termini are not readily apparent, the report documents the schedule for closing the gap between improvements. Logical termini can include other state highways or traffic generators in the project area. Logical termini must be set on all projects so that the section being studied demonstrates independent utility and does not require actions beyond the scope of the proposed action.

It may be that system linkage is also an element of the P&N. As such, there needs to be a separate discussion of system linkage in the report. This section is strictly to clarify how and where this project fits into the state of Missouri highway system.

126.2.2 Overview of Purpose and Need

A general overview, or listing, of the elements of the P&N is required. A detailed discussion of each item should follow the list. Only list and discuss those items that are considered to be a problem associated with this project. For this discussion, safety and capacity are assumed to be elements of all P&N statements. However, if a project does not have a safety or a capacity problem, then the crash data and the level of service (LOS) data is summarized after System Linkage and before the Overview of Purpose and Need. For all other items listed and described hereafter, if they are not a need for the project, then they do not need to be included as an element of the project’s P&N.

For long projects, different sections may have different P&N's. For example an add-a-lane project that includes a bypass of a community may have one P&N for the rural add-a-lane sections and a separate, different P&N for the urban bypass section.

Crash Data and Safety Enhancements

A crash rate is calculated, as shown in EPG 128 Conceptual Studies, for each project and compared to the statewide rate for a similar class of highway. Crash rates are calculated for logical sections of long corridors based on change in traffic volume or site conditions. The statewide rate can be obtained from district traffic personnel. A 5-year injury rate and fatal crash rate are also calculated by substituting the 5-year total injuries value or total fatalities value for the 5-year total crash value in the formula. If these rates are greater than the statewide rate for a similar class of highway, the comparison is included in the study. The statewide rates used in the assessment are provided in the report.

Breaking a long project into sections will help in evaluating why crash rates are high. There may be a high crash rate going through a city while the rural sections show no problem. Additionally, sometimes crashes will be concentrated at specific intersections that might imply spot locations with safety problems rather than the entire route having a problem.

As an element of safety enhancements, bicycle and pedestrian facilities that are provided as part of the project are discussed.

Roadway Capacity

Existing roadway capacity is discussed in terms of Level of Service (LOS) as calculated with the Highway Capacity Software (HCS). Calculations are presented for the existing facility (the no-build option) for both construction year and design year. If there will be many years that pass between the date of the study and the anticipated construction year, an analysis of existing traffic volumes is also included. LOS is evaluated at all intersections with state highways or with cross roads having sufficient traffic to warrant concern. The LOS is also calculated for the ramps, the ramp termini and the weaving areas of an interchange, when applicable.

Based on the project length, change in facility conditions or changes in traffic volumes, the LOS calculations are done on logical sections in sequence. All information is summarized and discussed as it relates to the need of the project. Generally, MoDOT considers a LOS of C (off-peak) acceptable for rural roadways and a LOS of D (off-peak) acceptable for urban roadways in the design year. However, each project must be considered individually.

Roadway Deficiencies

A complete discussion and tabulation of roadway deficiencies needing correction is presented. This may include substandard vertical grades, horizontal or vertical curvature, pavement or shoulder width, stopping sight distance, clear zone, and so on. Any deficiencies discussed are tabulated and/or illustrated in some manner so the reader knows where the deficiencies occur and what percent of the total length is considered deficient.

Additional Justification

Additional information such as needs associated with system integrity, flooding, legislative directive and public request, planned development or any other identified need may be used to justify the P&N of the proposed improvement. Each item used is discussed separately and in sufficient detail so the reader can understand the extent of the concern.