California Air Resource Board (CARB) Information & Links
California Air Resources Board website home page is a good start place for all the info:
PERP “Portable Equipment Registration Program”
This is for any engine mounted on a trailer, like a chipper or stump grinder.
PERP Questions and Answers
Here’s a PERP FAQ sheet with lots of answers to your questions.
Diesel Off-Road On-Line Reporting System (DOORS)
DOORS is an online tool designed to help fleet owners report their off-road diesel vehicle inventories and actions taken to reduce vehicle emissions to the Air Resources Board (ARB), as required by the In-Use Off-Road Diesel Regulation.
Visit the DOORS system here: