Reducing Transportation Greenhouse Gas Emissions Through the Development of Policies Targeting High-Emitting Trips

Traffic emission inventories have been under development for decades, often relying on data from traffic assignment models, ranging from macroscopic models generating average link speeds, to more detailed microscopic models with instantaneous speed profiles. Policy testing within such frameworks has often focused on identifying changes in total emissions, or in emissions aggregated at a zonal or street level. Emissions from specific trips or trajectories are seldom analyzed, although reductions in greenhouse gas (GHG) emissions can be achieved more efficiently when targeting high emitters. In this paper, we propose a different approach to reducing transportation GHG emissions, by catering policies to specific trips based on their emission burden. We focus on the City of Toronto downtown. Using second-by-second speed data for entire trajectories, GHGs (in CO2eq) and nitrogen oxides (NOx) emissions were estimated. We observe that the destinations attracting the highest trip emissions tend to be in the hospital and financial districts. Trips originating and ending in the downtown area are responsible for a small share of total emissions, although they have high emission intensity. Removing trips with high total emissions and high emission intensity led to significant reductions in CO2eq and NOx emissions, whereas removing shorter trips, did not have a significant influence on total emissions nor emission intensities.