A Decision Support System For Optimal Selection Of Roadway Alignments Using Sustainability Metrics

In this study, a decision support system is developed for evaluation and comparison of alternative geometric alignments based on their sustainability ratio determined from fuel consumption (environmental impact), safety (social impact), and earthwork (economic impact) as follows: a) Development of a Fuel Consumption evaluation model associated with roadway geometric design parameters, which evaluates and compares alternative alignments based on their fuel efficiency. b) Development of a Sight Distance evaluation model that evaluates and compares the alternative alignments safety based on their available and required sight distance profiles. c) Development of a Terrain Disturbance evaluation model that evaluates and compares the alternative alignments earthwork and minimizes the environmental impacts on natural terrain shape.

The formulation for all three models is then implemented in AutoCAD Civil 3D software package (programmed in Visual Basic language) to automatically evaluate any given alignment based on these three metrics. The developed model provides the tools for designers and planners to quantitatively compare and rate various alternatives and select the optimal alignment. This model is advantageous over existing rating systems that evaluate metrics qualitatively.