Explore the Data
Fairfield (Southlake Dr) → 23andMe (Mountain View)
Commute Duration
STI — Sakata Traffic Index
How to read STI:
STI > 0: leaving later adds to your commute time.
STI = 2: Mio's rule — every extra minute costs 2 minutes in traffic.
STI < 0: traffic is clearing fast enough that waiting shortens your drive.
STI ≈ 0: departure time doesn't matter much.
Demo data is modeled on typical Bay Area traffic patterns (I-80, Bay Bridge, US-101) using historical rush-hour curves. For live data based on current conditions, use Custom Analysis below with your own Mapbox token.
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Fah
You were RIGHT about 7–8 AM! The STI peaks at ~2.0. Your "2 minutes per minute" rule holds during rush hour. 😱
Fah
BUT — look after 9 AM. The STI goes negative. Traffic is clearing faster than I'm driving into it. The 9 AM commute is 30 minutes shorter than 8:30!
Mio
...so if you can't leave before 7, you should just wait until after 9?
Fah
Exactly. Unless I leave before 7 AM, I'm better off waiting until after 9. QED. 🎉
Mio
Fine. But you're still setting your alarm for 6:45.
Fah
Deal. 🤝
Fetching data…
The Origin Story
Mio
Fah, you really need to leave before 7 AM.
Fah
Mio 😩 7 AM is so early...
Mio
I'm serious. Every minute you leave after 7, you'll be stuck in traffic for 2 more minutes. Every. Single. Minute.
Fah
Two extra minutes per minute? That can't be right all morning. What about after 9 when traffic clears?
Mio
YES. Still terrible. Just leave early. I drive this every day.
Fah
...okay but I'm building a chart first. 📊
Commute Duration — Fairfield → 23andMe (Monday)
STI — Monday
Fah
Okay Mio, you were RIGHT about 7–8 AM! The STI peaks at ~2.0. Your “2 minutes per minute” rule holds during rush hour. 😱
Fah
BUT — look after 9 AM. The STI goes negative. Traffic is clearing faster than I’m driving into it. The 9 AM commute is 30 minutes shorter than 8:30!
Mio
...so if you can’t leave before 7, you should just wait until after 9?
Fah
Exactly. Unless I leave before 7 AM, I’m better off waiting until after 9. QED. 🎉
Mio
Fine. But you’re still setting your alarm for 6:45.
Fah
Deal. 🤝