Report: Innovative Technology: Evaluation of the Softree RoadEng Vertical Optimizer

Dec 18, 2017

In a recent published FPInnovations report, Softree Optimal was reviewed as a method of reducing the costs of road creation in steep terrain.


Innovative Technology: Evaluation of the Softree RoadEng Vertical Optimizer

March 2017 – Technical Report 47


Building roads on steep slopes and difficult terrain is a necessary yet often challenging endeavor in the natural resource industry. The magnitude of earthworks required for forest road construction on steep slopes can require substantial time and cost. The traditional role of planners is to create a road design in road engineering software, and then manually change and optimize its layout to minimize end haul volumes, excavation, and borrow and spoil pit creation.

Softree Technical Services, Inc. and the University of British Columbia developed vertical optimizing software to save time designing resource roads and to minimize construction costs. In 2016, FPInnovations conducted an assessment of the benefits of using the vertical optimizer on steep resource road designs from B.C.

FPInnovations compared the road construction costs for eight resource road designs created in Softree RoadEng® versus the same designs after applying the Softree’s vertical optimizer, Softree Optimal. The road designs were vertically optimized to two accepted resource road standards: the BC Ministry of Transportation and Infrastructure’s low volume road design standard, and the BC Ministry of Forests, Lands, and Natural Resource Operations’ Forest Road Engineering Guidebook road design standard. For the purpose of making relative comparisons, road construction unit costs were taken to be those default values specified in the optimizer.

The evaluation found that the Softree RoadEng® vertical optimization software produces road designs with lower total construction costs and reduced earthworks compared to manually completed designs. Additionally, the software is capable of producing a design in a matter of seconds or minutes, drastically reducing design time. Vertical optimization reduced the estimated construction cost by 13% to 22%, on average, depending on road design standard. Vertical optimization led to reductions in cut and haul costs, and in overhaul and end haul volumes. This was due to the optimizer being able to find more places to deposit fill material along the road. As a result, the optimizer was able to nearly completely eliminate the surplus of material at the end of the mass haul diagram.

FPInnovations also assessed the improvement to road users from optimized vertical alignments by simulating truck traffic over the design sections. FPInnovations’ Otto software was used to simulate log hauling truck speeds, and fuel consumption for a loaded log hauling truck negotiating each road. Travel speeds were consistently faster for designs optimized to the LVR standard; however, speeds on roads optimized to the FREG standard were sometimes slower than with the original design.

In order to realize the complete value of the vertical optimized design, road construction should have on-site quality and grade control to ensure construction is performed to an acceptable safety and quality standard.