Montréal's Ruelles Vertes — Resident-Led Green Alleys Since 1995, With Modest Measured Cooling (Canada)

Montréal's Programme des ruelles vertes, created in 1995 and delivered by boroughs, lets residents convert paved back alleys into planted, shared spaces; the city now has several hundred such alleys. It is one of the longest-running community-led urban greening programmes in North America.
A 2026 peer-reviewed study (Richmond et al., Ecosystems & People) assessed 53 publicly owned green alleys in Montréal and Trois-Rivières, alongside 23 grey alleys and 76 streets, under resident-led and municipally led governance. Green alleys provided more biodiversity support than grey alleys and adjacent street segments, but did not consistently increase the capacity to deliver ecosystem services.
Cooling effects were modest and highly variable: some green alleys performed no better, or even worse, than grey ones at certain times of day. Resident-driven alleys were more varied in design, while standardised municipal designs delivered more consistent cooling but may match residents' preferences less well.
The case is included as a cautionary, evidence-based example: community greening delivers biodiversity and social value, but planners should not assume it replaces targeted heat or stormwater measures. Blue-green alley pilots (e.g. Pointe-Saint-Charles) are a newer variant that disconnects roof drains from the sewer.

Read the full analysis: https://www.biorxiv.org/content/10.1101/2025.07.11.664403v1.full