FMCANationalOffice Report post Posted December 17, 2012 There have been several inquiries to the FMCA Office as to whether the new RETROACTIVE regulations in California on diesel engines apply to motorhomes. The answer is NO. http://www.arb.ca.go...s/tb-faq.htm#tb Scroll down to: Truck and Bus Regulation FAQs FAQ #9 reads: Are any vehicles exempt from the Truck and Bus Regulation? Certain vehicles are exempt from the Truck and Bus Regulation, and are not subject to any requirements. Examples include certain personal trucks with a pick-up bed used exclusively for personal use, motorhomes, emergency vehicles, historic vehicles, and military tactical vehicles. Please see Page 1, Section C of the Truck and Bus Regulation for the entire list of exempt vehicles. Share this post Link to post Share on other sites