Temporal Assessment of the Embodied Greenhouse Gas Emissions of a Toronto Streetcar Line

Transportation greenhouse gas (GHG) emissions often account for the largest share of urban GHG emissions. Consequently, large-scale reductions in urban GHG emissions will not be possible without significant improvements in the transport sector. Increasing public transit mode share is widely promoted in efforts to reduce GHG emissions from transport. Large increases in public transit use will require the provision of new transportation infrastructure, which is itself GHG intensive. This paper presents a time-dependent analysis of the embodied GHG emissions associated with construction and reconstruction for the refurbishment and street redesign of the 510 Spadina streetcar route in Toronto, Canada during a 38-year period. From 1987 to 2015, the embodied emissions in the line’s civil infrastructure are calculated as 27.4 kilotons of ${\mathrm{CO}}_2$ equivalent (${\mathrm{ktCO}}_2\mathrm{e}$). It is expected that, by 2025, further reconstruction of the right-of-way (ROW) will increase embodied GHG emissions to $32.1{\mathrm{ktCO}}_2\mathrm{e}$. Overall, reconstruction projects increase GHG emissions by 25.9% beyond initial construction. When accounting only for at-grade infrastructure, reconstruction increases embodied emissions by 45.8% during the 38-year study period.