Category:235 Preliminary Plans

Key Points

Forms and Figures

235.1 Purpose

A preliminary plan is developed to show preliminary geometric details, and includes design criteria, proposed alignment, profile, tentative grade, tentative right of way, schematic intersection or interchange layouts, bypasses and pertinent topographic features (see example plans).

The preliminary plan is a design tool and is prepared to develop and convey basic design criteria, basic geometric details and recommendations on which the detail plans are to be developed.

235.2 Procedure

The district prepares preliminary plans. The preliminary plan is prepared once horizontal and vertical alignment and tentative right of way limits have been established. Where the horizontal alignment is to tie into existing roadways or alignments, the tie location is be based on field survey measures and verifications. The district will obtain property ownership information to show on the preliminary plan as early as possible during its preparation. The soil survey is started as soon as possible so as not to delay the completion of the preliminary plan. This is done with a minimum of field survey staking until the preliminary plan has been completed. Basic design criteria and major geometric details shown on the preliminary plan are not changed during the development of detail plans without consultation with the Design Division. Completion of the preliminary plan allows the district to proceed with a public hearing.

A preliminary plan showing topographic features, including major overhead and underground utilities, basic design criteria, proposed horizontal and vertical alignment, proposed geometric details including interchanges, intersections, bypasses, geological features that have a significant effect on location or design, major drainage features, traffic data and proposed typical sections is prepared. For both conventional route and photogrammetric surveys the survey centerline and profile is shown on the preliminary plans. The centerline is not precisely computed or staked in the field until after approval of the preliminary plan.

Property lines and owners, soils information, and other required details are also shown. If limited access or fully limited access right of way is involved, points of access are shown. Points of access are developed in coordination with district right of way and legal staff, particularly in regard to the adequacy of any remaining access and the potential economic consequences of limiting or removing access. Additionally, access points are determined in accordance with Access Management Guidelines. For fully limited access right of way projects where construction will be staged and the ultimate facility will not be completed for a number of years, careful consideration is given to providing temporary access points for the initial project. For urban projects more detail including proposed width and percent grade for entrances may be desirable.

Basic design criteria used for roadway design are contained in numerous locations.

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 Right of Way Plans

748 Hydraulics and Drainage (for Bridge and Drainage issues)

A Design Exception Information form must be prepared and submitted when the criteria used on a project varies from established design criteria.

235.2.1 Coordination

Design Division Liaision Engineers and other personnel are available to review, advise and assist the district during the preparation of the preliminary plan.

235.2.2 Traffic Operations

Close liaison with district traffic personnel is extremely important in the development of the preliminary plan for the improvement. Throughout development of the preliminary plan and the design plans, district traffic engineering personnel are consulted to ensure proper traffic operations. Careful consideration is given to their recommendations. Those recommendations agreed upon are incorporated into the design plans.

235.3 Preparation

The preliminary plans (see example plans) are most often prepared in plan sheet format (22" x 34" (560 mm x 865 mm)). However, from time to time they may be prepared on a roll plan profile sheet plotted to a scale of 1" = 200' (1:2000) for rural areas, and 1" = 100' (1:1000) or 1" = 50' (1:500) for urban areas. A vertical scale of 1" = 10' (1:100) or 1" = 20' (1:200) is used for the profile of both urban and rural areas. The length of roll plans should be held to a maximum length of 30 ft. (9 m). If a project requires a longer preliminary plan, the plan should be broken into two sections. For short projects, such as bridge replacements, the use of plan sheets is recommended for the preliminary plan.

235.3.1 Methods

When a roll plan profile sheet (i.e. "strip map") is used, the plotting of alignments and profiles is planned to minimize the number of breaks. Sufficient room is reserved at the beginning and end of the preliminary plan for title, typical sections and basic design criteria. Neatness is encouraged and good legibility is required regardless of which method (plan sheet format or "strip map") is used to prepare the preliminary plan.

235.3.2 Topography

All important topographic features are indicated so that alignment controls are evident in reviewing the preliminary plan (see example plans). Cemeteries, Section 4(f) or 6(f) land, major utilities (underground and overhead), buildings, quarries and other such features are indicated along with the meander and direction of flow of streams, creeks and lesser draws. Landlines and descriptions are indicated along with village and city limits.

235.3.3 North Points and Profile Elevation Datum

North points properly orientated to the centerline are indicated on each sheet, or at the beginning and end of the preliminary plan, at approximately one-mile (one-kilometer) intervals, and adjacent to all breaks in the centerline (see example plans). The elevation datum on which the profile is plotted is also indicated on each sheet, or at the beginning and end of the preliminary plan, at approximately one-mile (one-kilometer) intervals, and in both directions at all breaks in the profile.

235.3.4 Right of way

Tentative right of way lines are included on the preliminary plan, along with property owners and property lines (see example plans). The right of way lines are approximations of those which will be required to construct the improvement in accord with the details recommended on the preliminary plan. The following note is placed on the title sheet of the preliminary plans (when the plan sheet format is used) or near the typical section on the preliminary plan (when the strip map format is used): "THE DESIGN GUIDE FOR THE WIDTH OF RIGHT OF WAY FOR THIS PROJECT WILL BE _____________ FEET (METERS). MORE OR LESS RIGHT OF WAY AS WELL AS OTHER PROPERTY INTERESTS MAY BE SECURED TO SATISFY THE REQUIREMENTS OF THE DESIGN FEATURES OF THIS PROJECT." When controlled access right of way is to be acquired, the note shall include the statement: "CONTROLLED ACCESS RIGHT OF WAY IS TO BE ACQUIRED FOR THIS PROJECT" or "PARTIAL CONTROLLED ACCESS RIGHT OF WAY IS TO BE ACQUIRED FOR THIS PROJECT". When fully controlled access right of way is to be acquired, the note shall include the statement: "FULLY CONTROLLED ACCESS RIGHT OF WAY IS TO BE ACQUIRED FOR THIS PROJECT".

235.3.5 Typical Sections

The typical section for the main line roadway is shown after the title sheet (when the plan sheet format is used) or at the beginning of the preliminary plan (when the strip map format is used) (see example plans). A typical section showing a superelevated section is not necessary. The typical section is drawn to scale and in sufficient detail to plainly indicate the criteria to which the roadway is planned. Where more than one typical section is required, the limits to which each section is applicable are plainly indicated. The typical sections are complete except for surface and base types and thicknesses. This information is determined in accordance with methods discussed in an article entitled Thickness Determination. The district may recommend a surface type and type of stabilized shoulder, but notations on the preliminary plan are restricted to light, medium or heavy duty.

Typical sections for other than the main line roadway, such as ramps, crossroads, supplementary routes, service roads, outer roadways, bypasses, etc., are shown following the main line roadway typical section sheet(when the plan sheet format is used) or on the preliminary plan in the vicinity of the proposed road or ramp (when the strip map format is used).

235.3.6 Title

The preliminary plan is properly titled on the title sheet if prepared on plan sheets, or at both ends if prepared on a roll (see example plans). If the preliminary plan includes revisions or modifications to a previously approved preliminary plan, it is marked and titled "Revised". The anticipated posted speed, design traffic data and functional classification are indicated adjacent to the title.

235.3.7 Grades

The tentative grade line is indicated on the profile section (see example plans). Those topographic features and improvements that establish elevation controls are taken into consideration. The grade line should provide balanced earthwork insofar as it is practical to estimate a balanced grade line with the profile information and knowledge of the location. In general, no attempt is made at this time to precisely establish a balanced grade line. The typical section is used without modification for special ditches, cut classification, etc. The vertical P.I. stations and elevations, as well as the rates of grade, are indicated. The length of all vertical curves, stopping sight distance at crest, and the "K" value at sag vertical curves are included. Preferred grade and vertical alignment controls are discussed in 230.2 Vertical Alignment. Passing sight distance controls and data are not noted or indicated on the preliminary plan. However, they are clearly stated in a letter of transmittal to the district engineer asking for approval of the preliminary plan and in the letter to the Design Division which transmits the approved preliminary plan.

235.3.8 Intersecting Roadways

All intersecting roadways are shown on the preliminary plan including those that are to remain open as at-grade intersections, grade separations, or interchanges (see example plans). Their centerline and profile are included on the preliminary plan. The stationing of the crossroad proceeds from left to right unless the crossroad is a state route on which the stationing has already been established. Schematic details are included for all intersections in sufficient detail to indicate generally the plan for developing the intersection. The crossroad profile is plotted on the profile section of the map, and the proposed grade is shown. Grade controls for intersecting roads are discussed in 233 At-Grade Intersections. Typical sections showing surface type, surface width, and roadway width for all existing and for all proposed replacement roads (which are to remain open) that intersect the main roadway are required.

235.3.9 Railroads

Paralleling railroads are shown where the survey is close enough that a common right of way line will be used, or where the proposed work will encroach upon the railroad right of way. Where the survey crosses a railroad, the location of the railroad, the railroad profile and railroad stationing are shown. Additional information concerning the relationship between the roadway and the railroad is found in 643.4 Railroads.

235.3.10 Interchanges

A schematic drawing showing general details for all interchanges is included (see example plans). Ramp profiles and tentative grades are shown on the profile portion of the preliminary plan, or may be shown on supplemental profile sheets. The location of ramp base lines, the direction of ramp stationing, and the proper identification of ramps are discussed in 234 Interchanges. Preliminary plans include geometric details for all 234.2 Diamond Interchanges. For other interchange types, additional details may be necessary as covered in 234.3 Directional Interchanges, 234.4 Single Point Urban Interchanges, and 234.5 Cloverleaf Interchanges. An example of acceptable preliminary plan details for interchanges is available. Precise computation of ramp base lines and ramp stationing is not required at the preliminary plan stage. The central angles for ramp curvature are scaled from the drawings, as is the ramp stationing.

235.3.11 Design Traffic

In addition to the main roadway design traffic volume required on the preliminary plan the same information is shown for interchanges and for all at-grade intersections if either or both of the crossroads have over 400 average daily traffic (ADT) (see example plans). If design traffic volumes indicate auxiliary turning lanes may be warranted, the district will request design turning movements from the Transportation Planning Division. Discretion is used in requesting design turning movements. Design traffic movements (ADT) and design hourly volume (DHV), or percentage of ADT for peak hour volume, are shown as a schematic diagram on the interchange layout or intersection layout.

235.3.12 Soils Information

A soils survey is requested from the district geologist as soon as the roadway template, alignment and tentative grades have been established with a reasonable degree of certainty during development of the preliminary plan.

235.3.13 Pavement Thickness Determination

After the preliminary plan is completed, the district requests a pavement thickness determination for the mainline and any other roadways associated with the project from the Pavement Team in the Construction and Materials Division. The request includes instructions to furnish the Design Division a copy of this information.

All projects that contain paving will be developed to permit alternate pavement bids. If there is a need to specify one pavement type over another on any project, the core team will justify their recommendation in a letter to the Director of Program Delivery. The project manager is responsible for documenting the reasons for the decision on the SIMS Form.

235.3.14 Handling Traffic

Consideration is given to the manner of handling traffic during construction, particularly at the ends of the project or where the location crosses more important existing roads. The locations of necessary bypasses and proposed profiles are indicated on the preliminary plan.

235.3.15 High Water Data

The design high water elevation at major stream crossings is indicated on the preliminary plan since this elevation will usually control the grade in the area of the stream crossing.

235.3.16 Soil and Cut Classification

Soil classifications (i.e., Class A, Class C etc.) are indicated by a note at the top of the profile portion of the preliminary plan. The approximate strata of various cut classifications are also shown on the profile portion.

235.3.17 Termini Controls

The alignment and profile of the existing roadway at each end of the proposed improvement are indicated for a sufficient distance, generally at least 1000 ft. (300 m) from the ends of the improvement. This allows a proper review of the connecting alignment and grade.

235.3.18 Examples

Examples showing necessary details and methods for showing details on preliminary plans are available.

235.4 Project Limits

It is desirable to designate limits on federal aid projects eligible for 100% federal funding and for "Bridge Funds" (eligible for 80% federal funding) at the preliminary plan stage. Project items eligible for 100% federal funding include highway-railroad grade separations, traffic signals, highway signing, highway lighting, guardrail and impact attenuators. Costs for guardrail and impact attenuators should total $25,000 or more to be eligible for 100% federal funding. At the time of preliminary plan approval the district establishes these project limits. These limits should be indicated as approximate because final determination of grade line can result in minor adjustments.

235.5 Field Checks

When a trial grade line has been roughed in on the preliminary plan, the designer should make a field check to familiarize themselves with the job and to visually check the data displayed on the preliminary plan. Other necessary field checks are to be made as design progresses.

The project manager and the design team (including the district right of way agent) will conduct a preliminary field check prior to completion of the preliminary plan. This preliminary field check ensures that the preliminary plan reports the district's recommended design and it conforms with the approved environmental document.

235.6 Approval of Preliminary Plan

The preliminary plan for a full oversight project must be approved by the FHWA. The district submits the preliminary plan to the Design Division for review and approval and once obtained the Design Division submits the preliminary plan to the FHWA for approval. An updated cost estimate of the project is included in the transmittal letters.

For all other projects, the district engineer may approve the preliminary plan as long as established design guidance and policy are followed. If design exceptions (signed by the district engineer) are necessary, they must accompany the submittal of the approved preliminary plan to the Design Division.

In both situations, the district will provide the Design Division with three (3) copies of the approved preliminary plan.

Three copies (one for the Design liaision, one for cultural and one for environmental)of a written request for environmental services (RES) are submitted with the approved preliminary plan. Submission of the RES at this stage will enable earlier initiation of cultural resource compliance procedures and possibly prevent future project delays.

The letter of transmittal shall contain the following information:

Passing sight distance controls and data. Existing pavement type together with thicknesses of surfacing and base at the connecting ends of the project. Brief statements on borrow or waste requirements. Utility concerns. The results of traffic capacity studies. Ideas for traffic control. Any information necessary to explain items not self-explanatory on the preliminary plan itself.

235.7 Distribution of Preliminary Plans

Prints of preliminary plans, which are furnished by the district, are to be stamped "PRELIMINARY PLANS - SUBJECT TO CHANGE." Originals of approved preliminary plans are retained in the district. Originals and reproducible copies are not to be loaned to others for printing. Complete preliminary plan prints are released only to local government. There is no charge for a reasonable number of prints for use by these agencies. Prints are furnished to anyone desiring coverage of individual properties, including isolated tracts at interchange areas. This includes oil companies and possible land speculators, but it is not our intent to supply them with prints of the entire preliminary plan. The charge for prints to other than local subdivisions of government will be in accordance with established pricing information.

235.8 Airports

If a highway improvement is located within 2 miles (3 km) of an existing airport, a letter is submitted to the Design Division with the approved preliminary plan. If the direction of the runways, or the elevations of the surrounding terrain, indicate there is obviously no conflict with the glide clearance at the highway crossing, a statement to this effect is made in the letter. No further information will be required to handle the matter with the proper authorities. However, if the direction of the runways, the proximity of the airport to the highway or the elevations of the surrounding terrain are such that the glide clearance at the highway crossing is questionable, a section of a county map of scale 1" = 2 miles (1:50 000) showing the location of the airport in relation to the limits of the proposed highway improvement is submitted with the letter.

The notice and submittal requirements of Federal Aviation Regulation Part 77 shall be followed if any highway improvement is located near an airport. Notice criteria can be found online at http://www.faa.gov/airports_airtraffic/airports/regional_guidance/central/construction/part77/#who Highway improvements located near airports shall also be coordinated with the Aviation Section in Multimodal Operations. The airspace filings can be submitted electronically through FAA’s website at https://oeaaa.faa.gov/oeaaaEXT/portal.jsp.

Particular attention must be given to all types of signs, light poles, cranes, and large equipment that may require notice as outlined in F.A.R. Part 77. The names and locations of civil and private airports in Missouri can be obtained from the "Missouri Aeronautical Chart" available from the Aviation Section in Multimodal Operations.

235.9 Project Scoping Documentation

Following approval of the preliminary plan and the public meeting/hearing documentation of the project scope is updated as necessary by the project manager. Details of this procedure are contained in 104.11 Project Scoping Documentation.