California CARB Heavy-Duty Vehicle Emissions Inventory Data

The regulatory dataset that decides which engines may legally haul freight and push dirt in the largest US state market. The California Air Resources Board publishes the numbers every heavy-truck and equipment strategy in America eventually reacts to: EMFAC, the state's official emission inventory model for on-road mobile sources; the TruckStop compliance hub, where five heavy-duty reporting systems converge; and the Advanced Clean Trucks regulation, the country's first manufacturer zero-emission-vehicle sales mandate. EMFAC2025 v2.1.1 landed in June 2026; a Community-Level Heavy-Duty Vehicle Emission Inventory joined the platform in January 2026.

Three record families, one theme. Inventories estimate what the on-road fleet emits, by pollutant, vehicle category and area. Vehicle populations count what is actually registered, drawn from the DMV registration database behind the EMFAC Fleet Database. Compliance records track who reported under which program - Advanced Clean Fleets, Clean Truck Check, Off-Road Diesel, Advanced Clean Trucks itself and Transport Refrigeration.

Get a sample of this dataset - name your program, weight class and geography, and real rows come back before you commit to a feed.

Three row shapes cover the catalog, one per record family, shown in delivered column order with the few values the documentation itself pins down already filled:

record_family: act_credit_summary      # Advanced Clean Trucks, ACTRS-derived
manufacturer:       Rivian
model_year:         2023
zev_credit_balance: 5039

record_family: emfac_inventory_extract
geographic_area:     <statewide region or census block group>
vehicle_category:    <on-road category>
model_year:          <vehicle model year>
emissions_inventory: <estimated exhaust or evaporative mass, by pollutant>
vehicle_population:  <fleet count for the same cut>

record_family: fleet_compliance_record
program:           Clean Truck Check
gvwr_threshold:    over 14,000 lbs
compliance_status: <filed under CTC-VIS>

The placeholders are deliberate: inventory cells are modeled outputs that move with the scenario and geography you run, so a printed number without your parameters would be fiction dressed as data. Name pollutant, program and area in the sample request and these three shapes return populated and join-ready.

Six core fields carry most of the analytical weight: the modeled inventory and population series from EMFAC, the manufacturer-model-year-credit triple from Advanced Clean Trucks reporting, and the gross vehicle weight rating thresholds that decide which fleets each program reaches. The dictionary below is that core; the deeper per-program filing fields are folded under additional fields on request.

• Geography - California statewide, with the Community-Level Heavy-Duty Vehicle Emission Inventory (live since January 2026) resolving the same on-road fleet down to census block group. Both levels come out of one modeling framework, so statewide totals and neighborhood hotspots reconcile.
• Temporal - EMFAC releases run from EMFAC2007 through EMFAC2025, with v2.1.1 the current vintage as of June 2026. Compliance history anchors to hard statutory dates - most consequentially January 1, 2023, since when the Truck & Bus Regulation has required 2010-or-newer engines in diesel vehicles over 14,000 lbs GVWR, on pain of DMV registration refusal.
• Granularity - cuts by vehicle category, model year, manufacturer and geographic area; block-group resolution in the community inventory; program splits by weight threshold (over 8,500 lbs GVWR under Advanced Clean Fleets, over 14,000 lbs under Clean Truck Check) and 25-hp-and-up for off-road diesel equipment.

One caveat worth planning around: EMFAC is a modeling framework, not a sensor network. Estimates shift between versions as methodology improves, so pin the version whenever you cite a figure.

API, files, or your warehouse. Daily, weekly, or hourly.

The five TruckStop reporting systems arrive unified into one schema - program, weight threshold, filing status - so a fleet's footprint across Advanced Clean Fleets, Clean Truck Check, Off-Road Diesel and Transport Refrigeration reads as one entity rather than four registrations in four dialects.

• Zero-emission transition tracking - ACT credit balances by manufacturer and model year show which OEMs are banking credits versus burning them - the earliest readable signal of who can sell compliant trucks in California at volume.
• Compliance-driven market sizing - cross the 8,500-lb and 14,000-lb GVWR cutoffs against registration counts and the addressable-fleet arithmetic falls out directly.
• Emissions exposure and siting analysis - EMFAC inventories quantify what each vehicle category emits, by pollutant and area, at block-group resolution - the scale depot, corridor and last-mile siting decisions argue about.
• Policy and citation work - statutory anchors like the January 2023 engine-age requirement and the DMV registration refusal mechanism are dated, nameable facts that survive review.

Market researchers and consultants get the regulatory denominator behind every California trucking and equipment sizing study. Competitive-intelligence and product teams get OEM credit positions and fleet-mix shifts ahead of the sales print. Data scientists get modeled series with published technical documentation to defend in review, keyed by category, model year and area. Journalists and academics get dated statutory milestones and block-group emission estimates - the raw material of local air-quality stories. Sales and growth teams get threshold-defined territories: every fleet above a GVWR line is a prospect with a deadline.

Four things, all knowable upfront. First, the core field definitions are reconstructed from program documentation rather than a publisher's formal data dictionary, so they are confirmed against real rows at first delivery.

Second, parts of EMFAC2025 reflect federal waiver actions under litigation and are flagged as not yet approved by the US EPA for SIP and transportation-conformity purposes. Treat those outputs as planning-grade, and pin the model version in anything citable.

Third, ACT credit figures surface as summary balances by manufacturer and model year, not a transaction ledger - you see who holds what, not every trade that got them there.

Fourth, "heavy-duty" here means several precise cutoffs, not one blanket class: 8,500 lbs, 14,000 lbs and 25 hp draw different program boundaries, so state your weight class in the sample request or you get the wrong denominator.