Trimble Alignment Planning proved extremely effective in Preliminary Corridor Development during the Corridor Alternatives Evaluation Process

"Trimble Alignment Planning, in conjunction with EPA GISST Data, was extremely effective in Preliminary Corridor Development during the Corridor Alternatives Evaluation Process. The large number of alternatives generated by Trimble Alignment Planning provided extensive and consistent options throughout a large and diverse Study Area". David Bacon - I-69/TTC Corridor Study GEC

Texas Department of Transportation (TxDOT) and Parsons Brinckerhoff Quade & Douglas (PBQD) the appointed General Engineering Consultant (GEC), commissioned the use of the Trimble Alignment Planning system for use on the 1,000 mile I-69 Trans Texas Corridor Study (I-69/TTC). Trimble Alignment Planning provides a unique corridor and route alignment optimization system, that allows planners to integrate environmental, community, cultural, engineering and cost factors into a single analysis. The I-69/TTC is investigating the feasibility of a multimodal facility containing high-speed passenger rail, freight rail, commuter rail, passenger vehicle controlled-access highway lanes, separate truck controlled-access highway lanes, and a multi-purpose utility corridor.

The purpose of the I-69/TTC project is to:

• • improve the international, interstate and intrastate movement of goods and people;
  • address Texas transportation needs for the next 20 to 50 years; and
  • sustain and enhance the economic vitality of Texas.

 

In October 2003, TxDOT opted for a Two-Tiered EIS approach to enable project teams to manage the phased multi-level decision making process and evaluate a project of this type, size and complexity.

Tier One may culminate in the approval of a preferred corridor, with the objective to identify the corridors that best meet the purpose and need while minimizing potential environmental effects. Trimble Alignment Planning was utilized to identify multiple corridors which were further analyzed and refined in the various study phases - Preliminary, Reasonable and Preferred.

Tier Two may identify appropriate modal and multi-modal alignments within the Tier One Corridor. Trimble Alignment Planning will be used to identify, analyze and provide data to justify the selection of these alignments.

Corridor Development

To facilitate the study process the 1,000 mile long, 50 mile wide study area was divided into 14 Sections of Independent Utility (SIU's), each with their own Section Engineer (SE) and project team, for the purpose of developing Preliminary Corridors for review and evaluation. The same corridor development and evaluation process had to be followed in each of the 14 SIU's. Appropriate procedures stipulating how to conduct a structured constraint by constraint iterative planning approach; and coordinate the interface between each section, were developed jointly by the GEC and Trimble Alignment Planning teams and then communicated to the SE's via structured workshops and formal training.

Benefits Identified Through the Use of The Trimble Alignment Planning System

• • IMPROVED METHODOLOGY - Trimble Alignment Planning allowed each of the 14 SIU teams to use a methodology that was replicable and quantifiable for the planning approach. Trimble Alignment Planning was not only used to collate, manage and analyze the teams large amount of electronic data and information, but was also able to assist in determining corridors and allowed review of results in a standardized graphical format.
  • ALTERNATIVES ANALYSIS - Trimble Alignment Planning enabled the planners and engineers to consider many alternatives, and review various "what if" scenarios to:
    • test various ranges of geometric parameters quickly;
    • consider various planning alternatives; and
    • minimize interaction with critically sensitive environmental resources.
  • USE OF COMMON PLATFORM - Trimble Alignment Planning provided a single platform to deposit, analyze, review and compare the vast quantity of data necessary for a project of this size and complexity.
  • EFFICIENT CORRIDOR IDENTIFICATION - By entering the required information layer by layer into the application and allowing the system to run in an unseeded (free to move horizontally) mode, the planners were able to identify trends or groupings of alternatives, indicating potential preliminary corridors and the effects each constraint had on the corridors in terms of relative cost and impacts. Further refinement of these scenarios assisted development of solutions with the least impact to identified critical environmental and cultural constraints.
  • FAST RESPONSE TO PUBLIC COMMENTS - Public comments were received indicating the need to look at alternatives outside the original national corridor. A single person from the GEC was able to analyze these additional areas and assess their viability in a few days with Trimble Alignment Planning, instead of months if analyzed in the traditional way.