Investigating Vehicular Emissions in the Halifax Regional Municipality

Abstract

Urban transportation systems are experiencing rapid changes, both in terms of new vehicle technologies and new mobility systems. This study presents a comprehensive emission modeling framework for Halifax, Nova Scotia, analyzing vehicle emissions across all fuel types for both private vehicles and public transit. It integrates activity-based travel behavior to provide a detailed understanding of emissions impacts. Results indicate that diesel vehicles, although comprising only 4.7% of the fleet, significantly contribute to GHG emissions, and their growing use could substantially increase overall emissions. Conversely, gasoline vehicles, despite their prevalence, show a gradual decline in emissions, although an uptick was observed in 2023 due to post-COVID travel patterns. This study also explores sustainable solutions, such as electric vehicles (EVs) and expanded public transit, to reduce emissions. This thesis examines the challenges Halifax face in promoting EV adoption and increasing transit ridership. Public transit's potential as a low-emission solution is hindered by low ridership and reliance on diesel-powered fleets. A key finding highlights the importance of using marginal emission factors (MEF) over average emission factors (AEF) to more accurately assess emission savings. Marginal Emission Factor (MEF) captures the impact of changing demand, unlike average emission factors, which assume constant emissions over time. Public transit has an AEF 17% lower than private vehicles. MEF analysis shows even greater reductions, with public transit emitting 45% less than gasoline vehicles and 53% less than diesel vehicles. The MEF-to-AEF ratio is consistent at 0.9 for private vehicles but drops to 0.53 for public transit, indicating limited energy impacts from changes in transit use compared to AEF estimates. Results shows that AEF often overlooks the incremental benefits of increased transit use, while MEF captures emissions reductions on a per-passenger-kilometer basis, making it a more effective tool for evaluating policy impacts. To reduce transportation emissions, the targeted policy recommendations from this study include implementing fuel-specific regulations, offering incentives such as rebates and improved charging infrastructure to encourage EV adoption, enhancing transit accessibility in densely populated areas, investing in electric transit fleets, and prioritizing transit infrastructure.