Use of Excess Off-Road CreditsBased on the Regulation as of September 7, 2012

If you own equipment subject to ARB's Off-Road Regulation and you retrofit one or more of your off-road equipment with a diesel particulate filter (DPF), and that retrofit exceeds your BACT obligation under the Off-Road regulation you can use that excess credit to meet your PM BACT Phase in obligations until the Jan 1, 2017 compliance date.

ARB portal to its Off-Road regulation is:
In-Use Off-Road Diesel-Fueled Fleets Regulation

If you own equipment subject to the Off-Road regulation we assume you are familiar with that regulation. The first compliance dates under the Off-Road Rule are as follows:

So if you installed a DPF this year on an off-road piece of equipment you could use that DPF to help meet your Truck and Bus Regulation PM BACT requirements for at minimum:

Once the compliance dates for the Off-Road regulation take effect, you may still be able to take credit for additional years provided the DPF retrofit is excess to your Off-Road BACT obligations.

The amount of credit is the hp of the excess off-road engine retrofit divided by 300. So for example if you retrofit 650 hp of off-road equipment you could apply treat two trucks as retrofit until that retrofit is needed to show compliance with the Off-Road regulation, or until Jan 1, 2017; whichever is earlier.