Source
All station records come from the Alternative Fuels Data Center (AFDC) station locator, via its public API, requesting every U.S. record with a fuel type of CNG or LNG. The AFDC is maintained by the National Laboratory of the Rockies for the U.S. Department of Energy. We pull the full set once a week, keep a dated snapshot of each pull, and rebuild every generated page from it. The pull date is printed on each page.
What counts as a station
A record appears in our lists and counts only if the AFDC marks it access: public and status: available. Everything else is excluded and reported separately:
- Private records (transit yards, refuse depots, utility garages, school districts, some port facilities) do not sell fuel to drivers. There are about as many of these as public stations.
- Planned records have an expected opening date that may or may not be met. We list the count on the national directory but never a planned station's address.
- Temporarily unavailable records are public stations the AFDC has flagged as not dispensing. They drop out of the counts until the flag clears, and the change shows up in the log.
"Public" in the AFDC can still mean "card key at all times" or "call ahead." We keep those, because a driver with the right card can use them, and we show the AFDC's access note on the listing.
The badges
| Badge | AFDC field | Rule |
|---|---|---|
| Quick-fill / Time-fill only / Quick + time-fill | CNG fill type code | Q, T or B as recorded. Missing means no badge. |
| 3,600 psi, 3,000 / 3,600 psi | CNG PSI | Every pressure listed in the field, formatted. |
| Class 8 OK / Up to medium-duty / Light-duty only | CNG vehicle class | HD, MD or LD as recorded. HD means the largest vehicles fit, so smaller ones do too. |
| RNG | CNG has RNG | True as recorded. The AFDC does not record the RNG share, so this means "renewable natural gas is dispensed here," not "all gas here is renewable." |
| 24 hours | Access days/time | The free-text hours contain "24 hours" or an equivalent. |
| Cards | Cards accepted | AFDC codes translated to names. Visa, Mastercard, Discover, American Express and debit collapse to "Credit/debit"; fleet cards are named individually. |
| Not re-verified in 18+ months | Date last confirmed | Shown when the AFDC's last verification is older than 18 months. It does not mean the station is closed; it means treat the details with more caution. |
| Network | Station name | Matched by name against a list of known operators. A utility-branded site run by a contractor is counted under the utility. |
State pages
A state gets its own page when it has at least five public, open CNG stations. States below that are listed, in full, on the national directory. Within a state, cities with three or more stations get a section of their own; the rest are grouped. Station rows are sorted by city and then by name, not by any judgement of quality.
Corridors
Each interstate is hand-traced as a chain of 25 to 55 waypoints through the cities it passes. A station is on the corridor if its coordinates fall within 20 miles of that trace. Its "mile" is the distance along the trace to the point nearest the station, measured from the corridor's starting city; the gap to the next station is the difference between two consecutive miles. The trace cuts corners the real road does not, so mileages are approximate, usually within a few percent, and always labelled "about." Where an interstate splits (I-35 East and West around Dallas and Fort Worth) the trace runs through both cities in sequence, which slightly inflates the mileage there. LNG stations on a corridor are shown but not counted in the gaps.
Change log
Each weekly snapshot is compared with the previous one by station ID. A public station appearing for the first time is logged as opened; a public station whose status flips to unavailable is logged as closed, and back again as reopened; a record that vanishes from the database is logged as removed. Private-to-public and public-to-private changes are logged as access changes. The log keeps the most recent 200 events.
Prices
We do not collect or estimate per-station prices. The only price figures on this site are national and regional averages from the DOE's quarterly Alternative Fuel Price Report, and every one of them carries the report date. DOE publishes each edition about three months after the month it surveys; we check for a new one every week and add it when it appears, and the price guide keeps the earlier editions as a history table.
Refresh and errors
The pull runs automatically every Sunday. If the public station count moves by more than a quarter between two pulls, the build stops and a person looks at it before anything is published, because that size of swing has so far always meant an API problem rather than a real change. If you find a listing that is wrong, report it to the AFDC, which fixes it at the source, or tell us.