The core regulatory options for heavier trucks are as follows:
PM BACT (best available control technology) is a truck with a diesel particulate filter (DPF), which is called a VDECS in the regulation.
In essence under the "PM BACT by model year" compliance path trucks are required to meet PM filter requirements based on the model year of the engine.
Under the "PM BACT Phase In" options fleets are required to comply based a percentage of the fleet (for example 30% of heavier trucks by Jan 1, 2012).
The small fleet option applies to fleets with 3 or fewer trucks larger than 14,000 lbs GVWR.
As can be seen from the Basic Compliance Structure chart, the regulation also provides certain exemptions and deferred compliance deadlines. These include:
To further complicate matters, BACT by Model Year affords an alternative PM BACT compliance schedule, and a variety of credits are available under the PM BACT Phase-In option.
Greater detail on all of these options can found by clicking on that option in the chart of compliance path alternatives.
For ARB's compliance option overview see "Compliance Requirements Summary" at:
Truck and Bus Regulation Fact Sheets and Reporting Documents