Data sources & vintages
- Gas stations — OpenStreetMap
amenity=fuel (Overpass snapshot, June 2026); brand/name/operator tags normalized to tiers.
- Traffic — federal HPMS 2020 (all functional classes) ∪ WSDOT current AADT (WA state highways; preferred on overlap).
- State gasoline anchor — EIA SEDS (MGTCP) through 2024.
- EV chargers — AFDC station locator (Esri Living Atlas live mirror, June 2026).
- Vehicle registrations — CA DMV fuel-type-by-ZIP (2018–2024) · WA DOL by county (2017–2024).
Demand model (v1)
Top-down disaggregation: each state-year's SEDS gasoline total is split across its counties by a
fuel-intensity-weighted fleet (gasoline 1.0 · hybrid 0.5 · plug-in hybrid 0.3 · diesel/BEV 0).
County sums match the state anchor exactly.
Station volume
Screening estimate — state/county demand split by format×√AADT (warehouse formats pump more;
busier roads carry more). It is not measured throughput.
Forecast (2025–2035)
Per-county EV-share logistic S-curve anchored on the observed 2024 share and 2018–24 trend; every
county trends toward the same ceiling C = 0.85 (EV-friendly metros sooner, rural later — never
frozen). Gasoline scales off the 2024 anchor as the weighted fleet shrinks. Slow/Mid/High pace brackets
policy uncertainty (credits, ICE mandates, gas prices are not modeled directly). Holds VMT, population
and remaining-fleet fuel economy constant — this is the EV-substitution effect only. Projected charger
counts grow proportionally to each county's EV fleet (chargers-per-EV held at the 2024 ratio); locations
are unknown, so they are never drawn on the map.
Station score
Weighted blend (sliders in the Scoring group, default Vol 35 / Disrupt 25 / Comp 25 / Traf 15) of four
0–100 components: Vol volume percentile within state · Comp fewer competitors within radius R ·
Disr county demand retention through 2035 at the selected pace · Traf nearest-road AADT
percentile. Percentiles are relative rankings within the selected state.