Mobility Responses to Snowfall in the Greater Toronto Area

Winter weather impacts travel volume, but in cities acclimatized to winter weather the effects are less clear. We study how snowfall impacts travel volume, across trip distances and road types, in the Greater Toronto Area for 96 snow days (2021–2025). Major snowfall days (≥5 cm, n=37) reduce trip volumes by 1.7% and vehicle-kilometers traveled by 2.3%, with effects concentrated on longer trips and higher-speed roads. To understand temporal responses around snowfall, we further examine a stricter subset of temporally independent major snowfall events, defined by grouping consecutive major snowfall days into event units and retaining events with clearly defined pre- and post-event days (n = 23). Mobility is significantly higher before these events than during them (+4.56 percentage points, p = 0.001), while post-event mobility does not show a statistically significant compensatory rebound. These findings suggest that major snowfall produces both suppressive and anticipatory mobility responses: travel declines on major snowfall days overall, while temporally independent events show evidence that forecasted snow may induce pre-event trip-making that offsets or exceeds same-day reductions over a short ±1-day window.