The utilidor is an environmentally and financially sustainable infrastructural solution for subsurface public right of way (PROW) congestion, known as the “subsurface spaghetti” problem, that has been created by utilities’ historical ad hoc practice of direct subsurface burial of transmission infrastructure. With the appropriate financial structure, the utilidor solution can capture the value of the subsurface PROW and account for the negative externality costs of direct burial. Construction costs in the New York City market exceed those in comparable large American cities and since the initial cost of utilidor construction can be twice the cost of direct burial, a life cycle cost benefit analysis (LCCBA) model for utilidor implementation is a pre- requisite for utilidor policy development.
Extensive literature on utilidor benefits and disadvantages and LCCBA methodologies has created a strong knowledge base for local utilidor LCCBA. The first LCCBA model for Town+Gown:NYC’s Utilidor Working Group was an excellent first look at the potential long-term cost savings from utilidor implementation as part of the City’s planned roadway reconstruction program, providing a directional “order of magnitude” sense. Using City cost data from five roadway reconstruction projects in Lower Manhattan completed as part of the post-9/11 reconstruction and subsequent associated roadway resurfacing projects, the team applied selection criteria consisting of cost, subsequent roadway resurfacings, zoning classification, level of vehicle congestion and impacts on residents, and selected the case study project that did not have a subway tunnel in the PROW, which would have increased the utilidor cost. This case study project had the second highest city initial cost, the third-largest number of subsequent excavation permits and the fourth highest number of 311 complaints, with a high proportion of roadway-related complaints; is located within three commercial zones and a residential zone; and, has an average of 11.775 vehicles passing through.
The team assumed a 100-year lifecycle of the utilidor, with two rehabilitation projects, no occurrence of street cuts for utility repair purposes after the utilidor was placed in service, a rate of increase in street cuts for current practice, a reduction in real property taxes paid by the private utilities, and an annual inflation rate. The team estimated the cost of constructing an off-site prefabricated utilidor using RSMeans cost data and costs of transportation, temporary relocation of existing utilities, installation, resurfacing and backfilling, and post-construction operation and maintenance, which the team assumed to be 10% of original construction costs. The model excluded costs associated with subway tunnels and surrounding businesses or higher traffic levels. The team defined five categories of stakeholders thought to be directly impacted by direct burial and defined predicted benefits accruing to them.
The LCCBA results suggested that implementing utilidors would result in decreased road surface maintenance costs and increased lifecycle of city streets, reductions in water loss from pipe breaks and emergency repairs for broken pipes, increased worker safety, reductions in accidental strikes, along with positive environmental and social externality benefits from reduced roadway construction. The team found at least a 90% reduction in costs in all impact categories from a utilidor as compared to direct burial, with the decrease in street cuts as the main cause for the cost reductions. The benefit-cost ratio was quite high, even after several sensitivity tests to increase the cost of the utilidor, increase the utilidor maintenance cost, reduce the projected street cuts, and increase the discount rate.
In reviewing the LCCBA, however, the Utilidor Working Group observed several aspects of the LCCBA model that require revision, including revising certain assumptions and calculations. Future refinements of this work-in-progress LCCBA will also aim to precisely quantify social costs, using available traffic and pollution data and include a partial franchise LCCBA focusing on subsurface PROW value and direct burial negative externalities and a partial LCCBA for integrated computer technology application for remote infrastructure monitoring.