u/amar1285

I’ve been thinking about how walkable a city actually is in 95°F heat. Google Maps will route you for distance, sometimes elevation. It won’t route you to the shaded side of the street — even when that’s the difference between a tolerable walk and a miserable one.

Building heights are open data in most major cities. Sun position is solved math. You can cast shadows onto the sidewalk network at any timestamp and prefer the shaded segments within a reasonable time budget. The implementation isn’t trivial but the physics is straightforward.

Some questions I keep hitting:

1. How would you weight shade vs distance? My current default is a 12% time budget — if the shaded route is more than 12% longer, fall back to fastest. Curious where planners would land on that ratio.

2. Should the directions tell you to cross the street when the shaded side switches mid-block? I do. It feels right. Curious if planners think it’s antisocial — the analog of “jaywalking on the recommendation line.”

3. What’s the right baseline for comparison? Are we measuring against shortest path, fastest path, or some idealized accessibility metric? The shade-as-equity argument feels like it lives somewhere between heat-island maps and ADA distance limits, and I haven’t found a clean framework yet.

4. Heat equity question that’s been bothering me: shade routing presumes the shade exists. In neighborhoods with low canopy and few tall buildings (often the same neighborhoods that score worst on heat-island indices), the tool offers less. Is “the shaded route” an equity-positive product if its value distribution mirrors existing disparities?

I’ve built a working prototype across 50+ cities — modeled every building footprint and height, cast shadows against the sun’s live azimuth, baked the sidewalk network at the borough or district level for the dense ones. Happy to share if folks are interested, but mostly curious what people who think about this stuff professionally would prioritize differently.

What am I missing?

I’ve been thinking about how walkable a city actually is in 95°F heat. Google Maps will route you for distance, sometimes elevation. It won’t route you to the shaded side of the street — even when that’s the difference between a tolerable walk and a miserable one.

Building heights are open data in most major cities. Sun position is solved math. You can cast shadows onto the sidewalk network at any timestamp and prefer the shaded segments within a reasonable time budget. The implementation isn’t trivial but the physics is straightforward.

Some questions I keep hitting:

1. How would you weight shade vs distance? My current default is a 12% time budget — if the shaded route is more than 12% longer, fall back to fastest. Curious where planners would land on that ratio.

2. Should the directions tell you to cross the street when the shaded side switches mid-block? I do. It feels right. Curious if planners think it’s antisocial — the analog of “jaywalking on the recommendation line.”

3. What’s the right baseline for comparison? Are we measuring against shortest path, fastest path, or some idealized accessibility metric? The shade-as-equity argument feels like it lives somewhere between heat-island maps and ADA distance limits, and I haven’t found a clean framework yet.

4. Heat equity question that’s been bothering me: shade routing presumes the shade exists. In neighborhoods with low canopy and few tall buildings (often the same neighborhoods that score worst on heat-island indices), the tool offers less. Is “the shaded route” an equity-positive product if its value distribution mirrors existing disparities?

I’ve built a working prototype across 50+ cities — modeled every building footprint and height, cast shadows against the sun’s live azimuth, baked the sidewalk network at the borough or district level for the dense ones. Happy to share if folks are interested, but mostly curious what people who think about this stuff professionally would prioritize differently.

What am I missing?

I’ve been thinking about how walkable a city actually is in 95°F heat. Google Maps will route you for distance, sometimes elevation. It won’t route you to the shaded side of the street — even when that’s the difference between a tolerable walk and a miserable one.

Building heights are open data in most major cities. Sun position is solved math. You can cast shadows onto the sidewalk network at any timestamp and prefer the shaded segments within a reasonable time budget. The implementation isn’t trivial but the physics is straightforward.

Some questions I keep hitting:

1. How would you weight shade vs distance? My current default is a 12% time budget — if the shaded route is more than 12% longer, fall back to fastest. Curious where planners would land on that ratio.

2. Should the directions tell you to cross the street when the shaded side switches mid-block? I do. It feels right. Curious if planners think it’s antisocial — the analog of “jaywalking on the recommendation line.”

3. What’s the right baseline for comparison? Are we measuring against shortest path, fastest path, or some idealized accessibility metric? The shade-as-equity argument feels like it lives somewhere between heat-island maps and ADA distance limits, and I haven’t found a clean framework yet.

4. Heat equity question that’s been bothering me: shade routing presumes the shade exists. In neighborhoods with low canopy and few tall buildings (often the same neighborhoods that score worst on heat-island indices), the tool offers less. Is “the shaded route” an equity-positive product if its value distribution mirrors existing disparities?

I’ve built a working prototype across 50+ cities — modeled every building footprint and height, cast shadows against the sun’s live azimuth, baked the sidewalk network at the borough or district level for the dense ones. Happy to share if folks are interested, but mostly curious what people who think about this stuff professionally would prioritize differently.

What am I missing?