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Section 5: Preliminary Engineering Design for Construction

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Overview

This section describes the elements required for preliminary design of construction projects, including highways, roads, bridges and alternative transportation-related projects and discusses a delegation of authority by the Federal Highway Administration (FHWA) to TxDOT in administration of projects with FHWA funds. As discussed in TxDOT’s Roadway Design Manual, different design guidelines apply to the design of new construction, rehabilitation and restoration projects. The local government (LG) must work with the TxDOT district to determine which guidelines apply before beginning design.

In general, schematic design will be required for most construction projects. Specialty projects such as building projects may require something other than a schematic.

If the LG does not use TxDOT’s or other approved guidelines, its guidelines must be submitted to TxDOT for review and approval. Ideally, these guidelines and code sources are identified in the advance funding agreement (AFA). In order to avoid delaying project development, the LG must coordinate and submit a written request for a design exception, as early as it is identified, to TxDOT staff for review and approval. The LG is encouraged to coordinate with TxDOT district staff during the Preliminary Design phase to ensure all design considerations are met. A more detailed discussion of this topic is included in the corresponding section of the Local Government Project Management Guide (LGPM Guide).

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Design Criteria

General

“Design criteria” is defined as those basic elements in Chapter 2 of TxDOT’s Roadway Design Manual (i.e. horizontal and vertical alignment, sight distance) and those elements that depend on scope of work and functional classification in Chapters 3-8 of the Roadway Design Manual (i.e. design speed, lane width, structure width). They include both the “controlling” and “non-controlling” criteria for which design exceptions, waivers and variances must be considered as listed in Chapter 1, Section 2 of TxDOT’s Roadway Design Manual.

Federal Requirements

  1. 23 CFR 625.3(a)(1) – Requires projects on the national highway system to be designed and constructed to FHWA-approved standards. 23 CFR 625.3(d) advises that the standards are applicable regardless of the source of funds.
  2. 23 CFR 625.3(a)(2) – Requires federally funded projects not on the national highway system to be designed, constructed, operated and maintained in accordance with state laws, regulations, directives, safety standards, design standards and construction standards.

State Requirements

  1. 43 TAC §§ 5.59, 15.56, 26.33 and 27.56 – Specifies that projects must be designed in accordance with TxDOT procedures, standards and guidelines. For regional mobility authority (RMA), toll and pass-through financed projects, preliminary design information must be sent to TxDOT for review and approval when the design is approximately 30 percent complete.
  2. Texas Transportation Code §222.104 – Allows TxDOT to enter into an agreement with public or private entities that provides for the payment of pass-through tolls for the design, development, financing, construction, maintenance or operation of a toll or non-toll facility on the state highway system. The agreement must provide that a municipality, county, RMA or regional tollway authority is required to meet state design criteria, unless TxDOT grants an exception.

Required Practices

In general, the LG must design roadway projects using the TxDOT manuals and other accepted guidelines or submit and obtain TxDOT pre-approval of alternate design standards. The LGPM Guide provides a more detailed discussion of the required practices and LG/TxDOT responsibilities for using acceptable design criteria.

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Exceptions to Design Criteria

General

Selection of design criteria is covered above. All reasonable effort must be made to produce a project meeting the established design criteria. However, there may be occasions when one or more design elements do not meet requirements. Exceptions may be granted as an engineering decision if properly documented, and supported.

There are three situations where formal approval must be given: design exceptions; design waivers; and design variances.

  1. Exceptions cover deviation from specific “controlling” criteria established by federal regulation.
  2. Waivers cover deviation from “non-controlling” criteria, those values listed as specific, numerical criteria but not one of the listed “controlling” criteria.
  3. Variances cover deviations from the Texas Accessibility Standards.

The Texas Department of Licensing and Regulation is the approval authority for variances. The approval authority for exceptions and waivers is established by policy and by agreement between the LG and TxDOT.

Federal Requirements

  1. 23 CFR 625.3(f)(2) – States that approval may be given on a project-by-project basis to designs not conforming to the minimum specified criteria. The determination may be made only after giving due consideration to all project conditions such as maximum service and safety benefits for the dollar invested, compatibility with adjacent sections of roadway and the probable time before reconstruction of the section due to increased traffic demands or changed conditions.

State Requirements

  1. 43 TAC §§ 5.59, 15.56, 26.33 and 27.56 – Requires projects to be designed in accordance with TxDOT procedures, standards, manuals and guidelines. TxDOT may be requested to approve deviations from criteria for specific elements. For RMA, toll and pass-through financed projects, preliminary design information must be sent to TxDOT for review and approval when the design is approximately 30 percent complete.
  2. Texas Transportation Code §222.104 – Allows TxDOT to enter into an agreement with public or private entities that provides for the payment of pass-through tolls for the design, development, financing, construction, maintenance or operation of a toll or non-toll facility on the state highway system. The agreement must provide that a municipality, county, regional mobility authority or regional tollway authority is required to meet state design criteria, unless TxDOT grants an exception.

Required Practices

The procedures for obtaining approval for exceptions, waivers or variances to the design criteria vary by type. The LGPM Guide provides the required practices and related LG and TxDOT responsibilities for design criteria exceptions.

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Design Level of Service

General

Level of service (LOS) is a measure of traffic flow and congestion. As defined in the Highway Capacity Manual published by the Transportation Research Board, the LOS is a qualitative measure describing operational conditions within a traffic stream – generally described in terms of such factors as speed and travel time, freedom to maneuver, traffic interruptions, comfort and convenience and safety. Selecting a design LOS is a conscientious attempt to reasonably accommodate traffic in the design year. The definition of a LOS is described in more detail in the LGPM Guide.

Federal Requirements

  1. 23 CFR 625.2 – Requires plans and specifications for projects on the national highway system (NHS) to provide for a facility that will adequately serve the existing and planned future traffic of the highway in a manner conducive to safety, durability and economy of maintenance, and to conform to the particular needs of each locality.
  2. 23 CFR 625.3(a)(2) – Requires federally funded projects not on the NHS to be designed in accordance with State directives and design standards.

State Requirements

  1. 43 TAC §§5.59, 15.56, 26.33 and 27.56 – Requires projects to be designed in accordance with TxDOT manuals, procedures, standards and guidelines. For RMA, toll and pass-through financed projects, preliminary design information must be sent to TxDOT for review and approval when the design is approximately 30 percent complete.

Required Practices

The LG must select a design level of service and submit it to TxDOT for concurrence. The LGPM Guide provides more information on this process.

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Geometric Schematic

General

The geometric schematic is a drawing of a computed alignment of the preferred alternate of a roadway or other linear facility. For a roadway, it shows features such as location of interchanges, ramps, and the number and arrangement of lanes. The schematic also conveys information to the public during meetings and hearings. TxDOT lists elements of the schematic in its Roadway Design Manual.

Federal Requirements

  1. There are no federal regulations requiring development of a geometric schematic.

State Requirements

  1. 43 TAC §15.56 – Requires projects to be designed in accordance with TxDOT manuals, procedures, standards and guidelines.
  2. 43 TAC §26.33(h)(3) – For RMA, toll and pass-through financed projects, preliminary design information must be submitted for TxDOT review and approval when the design is approximately 30 percent complete.

Required Practices

The LG is encouraged to prepare and submit a geometric schematic to TxDOT for approval for all transportation projects. It is a requirement for all design-bid-build projects on the SHS. The LGPM Guide provides specific practices and responsibilities for this task.

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Highway Access Management

General

An “access connection” is a facility for entry or exit such as a driveway, street, road or highway that connects to the highways under the jurisdiction of a public entity. “Access control” is the enforcement of specified authorization rules based on positive identification of the users and the systems they are permitted to access. Access management must be considered during the design of transportation projects on the state or national highway systems.

Proper access management assists in protecting the substantial public investment in transportation by preserving roadway efficiency and enhancing traffic safety, thus reducing the need for expensive improvements. Access management can also significantly reduce traffic accidents, personal injury and property damage. TxDOT policy and procedures for managing access to the state highway system is contained in TxDOT’s Access Management Manual. Additional information may be found in TxDOT’s Roadway Design Manual.

Federal Requirements

  1. 23 U.S.C. 111 – Prohibits states from allowing additional access points to the interstate system without the prior approval of the Secretary of Transportation. FHWA’s interstate access policy may be found on FHWA’s website.
  2. Other than specifying design criteria for federally funded projects, there are no specific regulations addressing access management. However, FHWA assumes a role to encourage and advance the development of state and local access management policies, guidelines and procedures for the management of facilities, and integrate these into established planning, policy and design processes.

State Requirements

  1. 43 TAC, Chapter 11, Subchapter C – Provides for approval of access connections to state highways. Includes granting authority to municipalities to develop and use their own access management plan.
  2. 43 TAC §§5.59, 15.56, 26.33 and 27.56 – Requires projects to be designed in accordance with TxDOT manuals, procedures, standards and guidelines. For RMA, toll and pass-through financed projects, preliminary design information must be sent to TxDOT for review and approval when the design is approximately 30 percent complete.

Required Practices

The LGPM Guide describes the required process and procedures and defines LG and TXDOT responsibilities for highway access management.

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Value Engineering

General

Value engineering (VE) is the systematic application of recognized techniques identifying the function of a product or service, establishing a value for that function and providing the necessary function reliability at the least overall cost. VE studies are required on federally funded projects on the federal-aid system with an estimated cost greater than $50 million and bridge projects with an estimated cost greater than $40 million. This requirement must be fulfilled before construction is authorized. The LG is encouraged to conduct the VE study soon after completion of the geometric schematic (approximately 30 percent design stage) to facilitate economical incorporation of all VE recommendations into the plans, specifications and estimates.

Federal Requirements

  1. 23 CFR 627.5 – Requires a value engineering study to be performed for all federally funded projects with an estimated cost greater than $50 million and for all federally funded bridge projects with a total estimated cost greater than $40 million.
  2. 23 CFR 627.9(c) – States that the requirement to conduct a value engineering study must be fulfilled prior to release of the request for proposals for a design-build project.

State Requirements

  1. There are no state regulations requiring the application of value engineering techniques to construction projects.

Required Practices

The LGPM Guide describes the practices for the LG and TxDOT district required for performance of a value engineering study.

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Right of Way, Utility and Railroad Certification

General

Issues involving the need for right-of-way acquisition, railroad coordination and utility relocations are identified during the Preliminary Design phase and usually are involved with construction projects. Ideally, all right of way is acquired, utilities adjusted and all necessary coordination with affected railroads is completed before construction begins. This gives the contractor unrestricted access to the project and minimizes the potential for delays during construction. The LGPM Guide provides a discussion of exceptions to this timeline. Detailed information regarding right-of-way acquisition, railroad coordination and utility relocation is contained in Chapter 6 – Right of Way and Utilities and Chapter 7 – Plans, Specifications & Estimate (PS&E) Development.

Since the timing for obtaining railroad permits can be quite extensive, it is not recommended that any project proceed to advertisement for letting without all required railroad permits in hand. Federal-aid projects require a statement, often referred to as the railroad certification, from TxDOT and the LG confirming the appropriate railroad coordination has taken place. This statement is required for all federal-aid highway construction projects, including projects not involving a railroad.

Encroachments are features within the right of way that are privately owned. Encroachments may remain if approved in writing. Otherwise they must be removed before construction is completed and the work accepted.

“Buy America” provisions apply to utility relocations on all federal-aid or on-system state projects. This topic is described in more detail in Chapter 7 of this Manual and the LGPM Guide.

Federal Requirements

  1. 23 CFR 635.307 – Prior to authorization to advertise for receipt of bids, right-of-way clearance, utility and railroad work must be so coordinated with the physical construction that no unnecessary delay or cost for the physical construction will occur. Right-of-way clearance, utility and railroad work performed separately from the contract for the physical construction of the project are to be accomplished in accordance with provisions of the applicable federal regulation.
  2. 23 CFR 635.309 – Requires a request for authorization to advertise for receipt of bids that include the following statements or certifications for all design-bid-build projects.
    1. Either all right-of-way clearance, utility and railroad work has been completed or all necessary arrangements have been made for it to be undertaken and completed as required for proper coordination with the physical construction schedules.
    2. Either all individuals and families have been relocated to decent, safe and sanitary housing or the state has made available to relocatees adequate replacement housing in accordance with the provisions of current FHWA directive(s). Additional required information is outlined.
    3. Either right of way has been acquired or will be acquired in accordance with the current FHWA directive(s) covering the acquisition of real property or that acquisition of right of way is not required.
    4. Statements relative to relocation advisory assistance and payments.
    5. The provisions of 23 CFR 645.119(b) have been fulfilled where utility facilities are to use and occupy the right of way.
  3. 23 CFR 635.309(p) – Requires the following certifications accompany a request to authorize final design and construction for design-build projects.
    1. Either all right-of-way, utility and railroad work has been completed or all necessary arrangements will be made for the completion of right-of-way, utility and railroad work.
    2. If right-of-way, utility and/or railroad services are to be included as part of the design-builder’s scope of work, then the request for proposals document must include: (1) a statement concerning scope and current status of the required services; and (2) a statement requiring compliance with the Uniform Relocation and Real Property Acquisition Policies Act of 1970, as amended, and 23 CFR Part 710.
  4. 23 CFR 710.403(a) – Requires all real property within a federal-aid facility to be devoted to highway use unless alternate use has been approved. Approval for encroachments to remain may be given only if the encroachment does not interfere with the safe, free flow of traffic.

State Requirements

  1. 43 TAC §15.56 – Requires projects be designed in accordance with TxDOT procedures, standards and guidelines.
  2. Based on precedents set in case law, the state prohibits an encroachment to exist without formal agreements with the owner of the encroachment. For more information, see TxDOT’s Right of Way Manual, Volume 2, Chapter 5, Section 21.

Required Practices

In general, the LG is responsible for right-of-way, railroad and utility coordination. The LGPM Guide provides the required practices and the LG and TxDOT responsibilities associated with this coordination.

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