Trimble Alignment Planning: Planning that protects the environment and cuts cost

"Trimble Alignment Planning was able to greatly improve the collaboration between the engineering and environmental project teams."
Transportation Corridor Agencies

To identify economically viable alignments that protect the environment, consider social constraints and meet engineering requirements.

Transportation Corridor Agencies (TCA) commissioned the Trimble Alignment Planning system for road and rail planning optimization to assist the project team in the complex environmental process associated with the 16-mile Southern California Foothill Transportation Corridor-South (FTC-S) project. After spending two years developing alternative route options for the toll-road project using conventional CAD and GIS systems, TCA and their appointed consultant, the Corridor Design Management Group had been unable to satisfy the multiple interests of different project stakeholders.

The Trimble Alignment Planning system is a unique methodology and technology that enabled the team to simultaneously consider environment, community, engineering and cost issues within a single analysis. It also allows the team to demonstrate consideration of "all feasible alternatives", which is required to achieve compliance with the National Environmental Policy Act (NEPA) and Section (4f) of the Department of Transportation Act in the United States.

The results for TCA were significant. They estimated that the application of the Trimble Alignment Planning system and the new methodology saved approximately 6 to 12 months in planning time, while delivering significant environmental and construction cost benefits. When TCA compared the results they were able to achieve with the Trimble Alignment Planning system against the alignments previously developed using conventional CAD and GIS systems, it was readily apparent that the new alternatives were far superior to many of the 19 previously selected alternatives. This allowed for a systematic elimination of many of the alternatives and reduced the number of alignments presented in the project DEIS/SEIR from 19 to 8.

 Figure 1

Figure 1 shows the three Trimble Alignment Planning refined alternatives (green, red and yellow) as compared to the two seed alignments (black and blue) developed using the conventional approach. The percent increase in comparative cost shows the refined alternatives provide a considerable reduction in cost compared to the seed alignments.

 Figure 2

The previous studies resulted in significant impacts on the newly developed residential neighborhoods in the Talega area as indicated in Figure 2.

 Figure 3

Figure 3 shows how the alignment derived using the new methodology avoids the Talega development as well as moving the alignment behind the ridge line to reduce visual impacts of the new facility. The improvements to the environmental and social outcome included:

• Reduced impact to riparian ecosystems (wetlands) from 107 acres to 39 or 49 acres for two options in one corridor, and 60 acres to 43 acres for alternatives in