Implications of hidden costs: Comparison of bitumen testing procedures

Traditional cost analyses used for process cost comparisons often ignore costs (e.g., waste disposal, regulatory compliance, long-term liabilities) that are lumped into general overhead but actually are incurred during the process. In this research, both a traditional cost analysis and a total cost assessment (which includes many often-neglected process costs) were performed on five potential methods of testing the bitumen composition of newly paved asphalt. In the past, the bitumen content of asphalt pavement was determined by tests using toxic solvents; alternative, less polluting methods have been developed that can replace the traditional solvent extraction method. In order to represent the uncertainties in the design and cost data (especially the liability costs) for this cost comparison, fuzzy set theory was used. A traditional economic analysis that included only the capital and operating and maintenance costs found that the most environmentally friendly process (ignition ovens) was only slightly less costly than two other options. The cost of the ignition ovens and two other options were similar enough to be considered within the range of uncertainty for the analysis. However, when the hidden costs related to the environmental, health, and safety aspects for a bitumen testing procedure were incorporated into the cost analysis, the cost comparison changed significantly; the most environmentally-friendly option, ignition ovens, was shown to be by far the least-cost option. Thus, incorporating hidden environmental costs into a cost analysis can have a significant impact.