7.2 Design Concept Conference

The Design Concept Conference (DCC) marks the beginning of the Final Design phase of project development and occurs after most of the preliminary engineering tasks have taken place. The DCC provides the opportunity for key people to review the preliminary engineering design and parameters, accept or change them, and formally endorse decisions. These decisions provide a foundation for the design team to commence detailed design work for plans production.
The DCC is especially useful for projects that:
  • Have different design teams involved in the preliminary engineering and final design phases of project development; and
  • Experienced a delay between the end of the preliminary engineering phase and the start of the final design phase.
For projects that have simple preliminary engineering tasks or no delay between preliminary engineering and final design, the DCC can be eliminated with the use of a PDCC (see
Section 4.2
) instead.
The purpose of the DCC is to:
  • Review basic design parameters, concepts and criteria that were established during preliminary engineering;
  • Review basic design parameters, concepts and criteria that were established during preliminary engineering;
  • Obtain concurrence with decisions made during Preliminary Engineering phase;
  • Determine additional data to be collected;
  • Evaluate the environmental document (if previously developed);
  • Review the Risk Register to update status on previously identified risks and identification of new risks; and
  • Update the DSR form (while all items will not be applicable to all projects, overlooking any item may significantly delay the project. This form will help ensure that the project team does not overlook potentially critical issues).
The following information should be available before holding the DCC as applicable:
  • ADA non-compliant pedestrian facility data;
  • Aerial photographs and topographic surveys;
  • Approved environmental document and commitments;
  • Bike/Ped/Transit needs analysis;
  • Environmental constraints (e.g., impacted properties, historical structures, wetlands, etc.);
  • Existing utilities;
  • Geometric schematic or geometric layout;
  • Hydraulic studies and analyses;
  • ICE documentation;
  • Identification of required permits and agreements;
  • LOS analyses;
  • Most recent construction cost estimate;
  • Preliminary geotechnical surveys;
  • Preliminary pavement design;
  • Preliminary typical sections;
  • Public involvement documentation;
  • Safety analyses;
  • Site visit photos and notes;
  • Traffic and crash data;
  • Utility coordination documents; and
  • VE analysis (if applicable).
If the Final Design team and Preliminary Engineering team are different, invite Preliminary Engineering team members to brief the Final Design team on project commitments, decisions, special problems or constraints.

7.2.1 Additional Data Collection

Additional or updated data is collected when this phase of project development begins. If the project is inactive for some time, it is possible that data may have changed and needs to be updated prior to commencing final design. Some of the items that are evaluated for changes include:
  • ROW maps.
    ROW maps need to be obtained as part of data collection. ROW maps are used to define limits of, and rights to use, state property.
  • Easements.
     If construction is proposed within existing easements, obtain a copy of the original conveyance document for the easement and check for restrictions on property use.
  • As built construction plans.
     As built plans provide important data regarding project features not apparent from the surface and geometric features, such as vertical curvature, which are not readily obtained by field surveys.
  • Traffic data.
    Traffic data is used to determine: the number of lanes needed, intersection channelization geometry, pavement design requirements, and desired safety-related improvements. If the project is part of the highway freight network, design vehicle type will influence pavement design, width, and curvature of turnarounds and intersections.
  • Crash data
    . Crash data can be obtained through the CRIS webpage to determine crash concentrated areas.
  • Site visit information.
     The project team uses the site visit to identify issues requiring additional studies that are not readily apparent from a two-dimensional plan set or three-dimensional modeling and to identify items which have significantly changed from data collected during preliminary engineering. Use the site visit to observe existing traffic patterns and operational/safety issues that may need to be addressed.
  • Utility information.
     Depending on the location of the project, in a rapidly growing area, utilities may have changed drastically during long lag periods between project development phases.
  • Preliminary cost estimates.
     Preliminary cost estimates are prepared during preliminary engineering. Cost estimates may change substantially due to the amount of time since the preliminary design was completed or due to changes in project scope. Update the project cost estimate as necessary and update the estimate in TxC.

7.2.2 Environmental Document Reevaluation

A reevaluation of the environmental document is required in situations discussed in
Section 5.4.3
. The reevaluation establishes whether the environmental decision remains valid or additional work is needed.

7.2.3 Additional Survey, SUE and Geotechnical Tasks

Additional survey, SUE and geotechnical studies may be needed to commence final design activities. Most field data collection will have occurred during preliminary engineering. However, as a large project develops, it is common for the designer to determine that existing data may be insufficient or need updating.
Additional field survey, including survey needed for performing final hydraulic studies, is begun as soon as the final ROW footprint is set (see
Section 4.7
), if possible. Additional SUE tasks are initiated after potential utility conflicts have been determined.
Similarly, additional geotechnical cores for bridge and/or retaining walls and sound walls are identified and initiated after locations are set during preliminary engineering. Geotechnical investigations also include obtaining data for designing high mast illumination, signals, and overhead sign structures.
These tasks can take several months and should be included in the project schedule.

7.2.4 Traffic and Safety Analysis

Final design phase analysis is a high-detail analysis that is often performed with more data than projects in other stages of development. While study limits for projects in this stage could be broad or narrow, they are well defined.
Refer to the TSAP Manual for details on the data and tasks to complete for traffic and safety analysis procedures to complete during this phase.
  • Coordination:
  •  District planning, design, pavement, construction, bridge, traffic, ROW, utility, laboratory and environmental staff
  •  Area office staff
  •  Maintenance staff
  •  Division staff (as appropriate)
  •  Local government staff (if applicable)
  • Available training:
  •  DES110 – Right-of-Way Considerations
  •  ROW101 – Utility Coordination
  •  TPD327 – TxDOTCONNECT Utility Functionality