About CTC Finder
What CTC Finder is
CTC Finder is an independent directory that helps truck owners, fleets and owner-operators find a CARB-credentialed tester for California's Clean Truck Check (HD I/M) program. It is not affiliated with, endorsed by or operated by the California Air Resources Board (CARB) or any government agency. We do not register vehicles, collect CARB fees or issue compliance certificates; those happen only in CARB's CTC-VIS system.
Where the data comes from
- Testers: CARB's public Clean Truck Check tester list, last downloaded November 1, 2026. Listing on that list is optional, so some credentialed testers are missing. We list 2,867 testing businesses in California and 506 outside California.
- Merging: CARB lists each credentialed person separately. Entries with the same phone number and ZIP code, or the same business name and street address, are shown as one business with a tester count.
- Cleaning: advertising text in names (phone numbers, "book online at…") is removed. Website addresses found in names are kept as the business website.
- Location: ZIP code centers from the US Census Bureau (2024 ZCTA gazetteer) and ZIP-to-county relationships (2020). Distances are approximate.
- Privacy: we never publish testers' personal names or email addresses. When a listing looks like a home-based or mobile tester (a person's name or an apartment address), we hide the street address.
- Prices and rules: guide facts come from CARB's fact sheets, FAQ and regulations (13 CCR § 2195–2198). Price ranges come from testers' published prices. Each guide lists its sources.
Refresh schedule
We refresh tester data from CARB every month and show a "last verified" date on every page. Featured listings are paid placements and are always labeled "Featured".
Corrections and removal
Testers can correct or remove their listing at any time: claim or update a listing or email hello@ctcfinder.com.