The Alan M. Voorhees Transportation Center at Rutgers University has developed, in collaboration with NJ DOT and NJ Transit, a tool that allows engineers to estimate the greenhouse gas (GHG) emissions associated with specific transportation construction practices for both highway and rail projects. This includes estimating emissions from material inputs, construction equipment activity, life-cycle maintenance, project staging inputs (including emissions due to road closures during construction) over the lifetime of a project. The product is a spreadsheet tool, the Greenhouse Gas Assessment Spreadsheet for Transportation Capital Projects (GASCAP) that will allow NJDOT personnel and potentially contractors to input project data from bid sheets and specify a maintenance plan for the life of the facility. Greenhouse gases are estimated on a life cycle basis using a cradle to grave approach that accounts for upstream emissions, i.e. extraction and processing of most materials, primarily fuels, aggregate and fill, cement, asphalt, steel, plastics, galvanizing materials, paint, and others, as well as direct emissions i.e. their application and downstream emissions, which include those associated with demolition, and disposal. At present the GASCAP tool has the ability to estimate upstream, and construction emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), black carbon particulate matter, air conditioning coolants, sulfur hexafluoride (SF6) and total global warming potential. This provides a comprehensive estimate that allows project engineers to compare how different project construction decisions may affect overall life-cycle GHG emissions. In addition, the current version of the model provides a technique to estimate extra emissions associated with growth of the highway network.

Currently the GASCAP model provides project specific estimates; our goal with this work is to apply the GASCAP tool to a wider range of alternative transportation construction projects to provide policy-makers with estimates that can inform higher-level decision making. Ultimately our goal is to provide a technique whereby estimates of GHG emissions can be estimated from basic information such as lane-miles or track-miles constructed, or rehabilitated, and to compare the GHG emissions associated with alternative construction and maintenance materials, practices, and techniques that are typically used in projects.

Parallel to this work, VTC is collaborating with San Jose State University’s Mineta Transportation Institute (under the auspices of the tier 1 transit research center, the National Mineta Transit Research Consortium (MTRC)) to estimate future transportation scenarios to reduce GHG emissions in 2050. This parallel research effort will analyze existing trends and policies aimed at reducing GHG emissions and will include a detailed modeling component of transportation and land use policy options. The work proposed here will be linked with the MTRC project to provide a means to estimate planning-level construction emissions that can be added to future transportation scenarios. Emissions associated with alternative plans, such as whether to build high-speed rail versus other modes of transportation, can be affected by these estimates. We will also use data and analysis from another recently awarded NJDOT project, The Impact of Freight on Highway Infrastructure in New Jersey, being led by another team at Rutgers. This project will allow us to better determine how highways deteriorate as a function of freight traffic and how this affects the life-cycle maintenance plans (and consequent GHG emissions) from maintenance activity, allowing us to update GASCAP with this additional data.

The primary objective of this proposed project is to enhance the GASCAP model by developing estimates of GHG emissions that are useful for policy makers and integrating these with future transportation scenarios.