Currently, smog inspections are required for all vehicles except diesel powered vehicles 1997 year model and older or with a Gross Vehicle Weight (GVWR) of more than 14,000 lbs, electric, natural gas powered vehicles over 14,000 lbs, hybrids, motorcycles, trailers, or gasoline powered vehicles 1975 and older.

Vehicles registered in areas subject to the biennial smog certification program are required to submit evidence of a smog certification every other renewal period. Owners of vehicles six or less model years old will pay an annual smog abatement fee for the first six registration years instead of being required to provide a biennial smog certification. The registration renewal notice mailed to you by the department will indicate if a smog certification is required. If a smog certification is required and you have not had a smog inspection, you may still pay your registration fees to avoid any late fees. However, you will not receive your new registration or year sticker until the smog information has been received by DMV.

NOTE: Upon initial registration, nonresident, diesel powered vehicles 1998 model year and newer with a (GVWR) rating of no more than 14,000 lbs, and specially constructed vehicles 1976 and newer require smog certification. The six or less model years old rule does not apply to these vehicles.

When you transfer a vehicle that is four or less model years old a smog certification is not required. (Determine the oldest-qualifying year model by subtracting three from the current year.) The four or less model years old rule does not apply to diesel powered vehicles. A smog transfer fee will be collected from the new owner . When a vehicle is more than four model years old, a seller must provide evidence of a current smog certification except when one of the following occurs:

The transfer occurs between a spouse, domestic partner, sibling, child, parent, grandparent, or grandchild.
A biennial smog certification was submitted to DMV within 90 days prior to the vehicle transfer date (a vehicle inspection report may be required for proof of certification).
Smog certifications are good for 90 days from the date of issuance.