| dc.description.abstract | In response to the increasing need to address global climate change, departments of transportation have adopted and promoted diverse mitigation measures to reduce source and enhance sinks of the greenhouse gas (GHG) emissions associated with highway management. Quantitative evaluations of the applicable mitigation measures from infrastructure design, construction, operation, and rehabilitation, however, are often lacking. Quantification efforts assist the agency in understanding the magnitudes of the overall GHG reductions and the effectiveness of each mitigation measure.
This study proposes and develops a framework to track the current and emerging mitigation activities by the Ministry of Transportation in Ontario (MTO). Mitigation measures related to materials, transportation, lights, trees, and traffic were selected based on data availability, popularity of the mitigation measure, ease of quantification, the extent to which GHG emissions can be reduced by the practice, and potential for future adoption. The framework incorporates the records from MTO’s Highway Costing System (HiCo) and builds on Ontario based emission factors and default activity values. Life-cycle GHG emissions and multi-year emissions impact are considered where applicable.
A standardized GHG mitigation tracking template, Province of Ontario Emission Tracker for Transportation (POETT) was designed based on the framework, and a case study was performed with 2017 HiCo data. The tool estimates that approximately 60 kilotonnes of GHG emissions were avoided in 2017 by MTO’s mitigation activities. Overall, material recycling and other material substitution dominated the reductions by avoiding the production of new materials. The dominance of this measure reflects MTO’s significant use of materials. The reduction value for each mitigation measure ranges from 1.04 tonnes carbon dioxide equivalent (CO2e) from using LED high mast lights to 13,572 tonnes CO2e from applying full-depth reclamation in place of traditional Mill & Overlay practice. Unit GHG emission reductions (e.g., kg/m2 GHG reduced by in-place recycling) and the percentage reduction of the mitigation measures were also calculated. Within uncertainty, the results compared well with values obtained from emission quantification tools and literature. Compared to California Department of Transportation’s mitigation of 161 kilotonnes CO2e in 2013, these results suggest that MTO is making meaningful reductions of emissions in its purview. Given limits on data availability, this estimate is considered a lower bound. In the future, additional data collection efforts (including quantities of supplementary cementing materials and detailed traffic data) could be used to further validate and enhance MTO’s capability in tracking GHG mitigation using POETT. | en |
