Tree canopy is important for preventing pedestrian falls

Very excited to share a paper I led published in the American Journal of Epidemiolgoy this week. We conducted pilot research to assess whether Emergency Medical Services data could be used to implement a multi-city, location-based case-control study investigating the association between tree canopy cover and locations of injurious pedestrian falls.

why does this matter?

Many cities have tree planting campaigns, particularly street trees, but these campaigns are controversial because street trees can cause sidewalk damage, and residents worry that this damage will increase the risk of falls. In many areas home/building owners are responsible for sidewalk maintenance and are liable if someone falls on the sidewalk in front of their building. Our work provides new evidence that urban trees, perhaps through cooling the local ambient environment, contributes to pedestrian safety. the research. ——

We analyzed data on tree canopy cover at 497 locations where Emergency Medical Services attended to pedestrians injured in a fall between April and September 2019 and at 994 carefully matched control locations. Tree canopy cover at each location where an injurious fall occurred and at matched control locations was measured using the 2019 National Land Cover Database. Average tree canopy cover at fall locations was 8 percent, compared with 14 percent at control sites. In adjusted analyses higher tree canopy cover was inversely associated with fall locations (adjusted OR across the inter-quartile range of canopy cover = 0.57, 95% CI: 0.45, 0.74).

the takeaways.

Our work provides new evidence that urban trees, perhaps through cooling the local ambient environment, contributes to pedestrian safety.

High temperatures can increase fall risk by adversely affecting human physiology and by degrading road and sidewalk surfaces. High heat softens asphalt and causes sidewalk pavers to pop out of alignment creating trip and fall hazards. The work we present in AJE supports cities’ initiatives to expand the urban forest and tree canopy cover.

in other news.

New York City has implemented a new rules to lower e-bike speed limits citywide and speed limit reductions at 250 locations by the end of 2025 in response to the increase in vulnerable road user injuries. Lowering the speed of e-bikes is very controversial as bike advocates argue that this will place cyclists in greater danger when bicycling next to traffic (based on the sustantial body of evidence in this space) and there are equity concerns, given that delivery cyclists in NYC are incentivized to complete orders quickly.

Sounds like some reseaarch is critical in this space to clarify the impacts of these rules on pedestrian, cyclists, and micromoblity injuries - so that political decisions are data-informed.