Designers: treat streets as urban ecosystems to cool heat and improve usability

April Webster said streets should be treated as urban ecosystems rather than solely transportation corridors: “Every layer of that system, the streets above, the stormwater below, and the people moving through it every day is equally important.”

Webster explained why trees are the “gold standard” for addressing urban heat: they provide shade and cool air through evapotranspiration, which reduces mean radiant temperature and improves comfort for people walking and biking. She recounted riding on a shaded section of El Camino Real and described the immediate cooling effect when entering tree canopy.

She pointed participants to mapping tools to identify priority planting locations: Cal‑Adapt’s urban heat maps, the U.S. Forest Service urban tree canopy viewer, and tree equity scores. Layering those data with health or vulnerability indices, Webster said, helps target investments where they will reduce exposure and health risk the most.

Webster also linked heat to air‑quality formation (ground‑level ozone) and discussed rural dust and valley‑fever risks from fallow cropland; she recommended vegetative buffers and CalEnviroScreen (and pollutant‑specific layers) to identify hotspots.

Why it matters: designing for comfort and usability — including shade and buffers — can increase walking and biking even under extreme heat and reduce exposure to air pollutants. Webster framed these design features as safety and usability improvements that should strengthen ATP applications.

What she did not do: Webster offered design guidance and tools; she did not propose new regulations or financial commitments during the plenary.