Planning Level Assessment of Greenhouse Gas Emissions for Alternative Transportation Construction Projects: Carbon Footprint Estimator, Phase II. Volume I: GASCAP Model. Final Report

摘要

The GASCAP model was developed to provide a software tool for analysis of the life-cycle GHG emissions associated with the construction and maintenance of transportation projects. This phase of development included techniques for estimating emissions from induced travel when a project involves a capacity expansion; a life-cycle maintenance module based on recommended procedures for maintaining a road surface over 50 years; an automated method for inputting construction equipment activity associated with selected project types; a method based on the Highway Capacity Manual for estimating emissions associated with project staging and the diversion of traffic around a worksite; methods for more easily updating emissions factors in the model; and, a variety of miscellaneous upgrades to account for SF6 emissions, upstream electricity emissions associated with asphalt, and incorporation of additional bid-sheet codes in the materials module. Four case studies to demonstrate the models usage were also conducted. These were: a large project case study (reconstruction of rt 35 in Ocean County) that demonstrated the full capabilities of the model; a smaller project (rt 47 resurfacing in Gloucester County) that focused on different staging options and the impact on emissions from traffic; an applied case study conducted in collaboration with NJDOT staff in the South Jersey regional office that focused on maintenance activities; and a demonstration of the relationship between the embodied fuel cost of a project and the GHG emissions.