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 the systematic elimination of many of the alternatives and reduced the number of alignments presented in the project DEIS/SEIR from 19 to 8.
The improvements to the environmental and social outcome included:
- Reduced impact to riparian ecosystems (wetlands) from 107 acres to 49 acres;
- Reduced impact to sensitive species by completely avoiding the Pacific Pocket Mouse habitat;
- Reduced landslide risk/disturbance limits by avoiding many of the existing landslides by identifying roadway geometry that more closely follows the natural terrain; and,
- Reducing residential displacement from 32 to zero homes.
- Minimized impact on existing utilities which avoids the utilities themselves having to be relocated to undisturbed areas with associated environmental impact.
In parallel to the considerable reduction in environmental and urban impact, the Trimble Quantm Alignment Planning System helped reduce earthworks and structures, delivering construction cost savings of more than $80 million.