Plain-language coverage of California's HD I/M program: what it requires, who it reaches, and where the rule is headed.
The January 2026 partial disapproval did not strike down the program for California fleets. Here is the distinction the headlines missed.
Read →If your trucks run California loads, the program reaches you regardless of where you are registered. What the EPA action changed, and what it didn't.
Read →An ongoing log of the federal-vs-state dispute and what each development means for compliance.
The consequence that actually grounds your truck is a DMV registration hold, not the inflated daily fines you have seen quoted.
Read →Who it applies to, what you have to do, what it costs, and the deadlines that matter. The complete starting point.
Read →How to build a compliance calendar before OBD-equipped vehicles move to four tests per year.